Technical Specification — Juliet Coffee Water System
For Drinking Water & Specialty Coffee / Beverage Application
| Field | Detail |
|---|---|
| Document Number | RO-SPEC-001 |
| Revision | Rev I — Procurement-anchored to BOM Rev H. Full change list: Progress. |
| Date | 21 April 2026 |
| Application | Drinking Water Production — Specialty Coffee, Ice & Beverage Service |
| Supply Voltage | 240 VAC Single-Phase, 60 Hz (USA) |
| Intended Use | Potable Water — Sanitary Construction Required |
⚠ ALL MOTORS, DRIVES, AND ELECTRICAL COMPONENTS MUST BE RATED FOR 60 Hz OPERATION
1. System Overview
This specification defines the requirements for a compact reverse osmosis (RO) water treatment system intended for commercial drinking water production in a specialty coffee shop environment. The system serves an espresso machine, an ice maker, and a drinking water filling station. The system shall be of full sanitary construction throughout all wetted surfaces and shall comply with applicable NSF/ANSI standards for potable water contact materials.
The system processes municipal or well feed water through sequential pre-filtration, RO membrane separation, UV disinfection, and controlled mineral re-injection to achieve a final product water profile optimised for specialty coffee extraction.
Two-Tank Architecture with UV Recirculation
The system employs a two-tank architecture with a continuous UV recirculation loop on Tank 1:
-
Tank 1 (T-101) — Buffer (15–20 gal) stores raw RO permeate. Sized for peak-hourly demand bursts (ice machine + T-102 fill ≈ 10 gal worst case) with margin, not for full-day storage — RO permeate output (30–90 gph) outpaces peak demand (~10–15 gph). A recirculation pump (P-102) continuously circulates T-101 water through a UV disinfection unit and back to prevent bacterial growth during storage. Valved branches off the UV discharge provide on-demand supply to the ice machine (direct, no minerals) and to the treatment path (mineral injection → Tank 2).
-
Tank 2 (T-102) — Small buffer (5 gal) stores fully treated product water (UV-disinfected, mineral-injected) ready for distribution to the espresso machine and drinking water station.
A dedicated distribution pump (P-103) supplies pressurised product water from T-102 to the espresso machine and drinking water station.
Process Flow Diagram
FEED ──► Sediment Filter ──► Carbon Filter ──► P-101 (RO Feed) ──► RO Membrane ──► T-101
(5µm pleated) (carbon block) (CRN1S-15, VFD) (XLE Pro-2540) (15–20 gal)
(USWPF-4520-05) (USWCB-4520-10)
│
┌────────────────────────────────────────────────────────── SV-RECIRC (N.O.) ◄┤
│ (recirculation return) │
▼ │
T-101 ──► P-102 (Recirc/Transfer, CRN1S-4, VFD, continuous) ──► UV ─────────────┤
(Pulsar PUV-200-20) │
│
SV-ICE (N.C.) ─────┤──► Ice Machine
│ (no minerals)
SV-TREAT (N.C.) ───┘
│
Mineral Injection
(3 × DDC 6-10 metering pumps)
│
Static Mixer
(Koflo 105955Q34R)
│
T-102
(5 gal)
│
P-103 (Distribution, ½ HP VFD — TBD)
│
┌──────────┴──────────┐
Espresso Machine Drinking Water
Filling Station
Process Sequence
| Stage | Process Step | Primary Function |
|---|---|---|
| 1 | Sediment Pre-Filter — 4.5″ × 20″, 5-micron pleated (US Water Systems 550-USWPF-4520-05) | Remove particulates, protect downstream media |
| 2 | Carbon Block Filter — 4.5″ × 20″, 10-micron coconut-shell carbon block (US Water Systems 507-USWCB-4520-10) | Remove chlorine, chloramines, VOCs, taste & odour |
| 3 | High-Pressure RO Feed Pump (P-101) — Grundfos CRN1S-15 A-FGJ-G-E-HQQE, 60 Hz VFD-controlled | Pressurise feed water to RO operating pressure |
| 4 | RO Membrane — Filmtec XLE Pro-2540 in US Water Systems 257-208238 2540 SS pressure vessel | TDS / ionic reduction via semi-permeable membrane |
| 5 | Tank 1 (T-101) — RO Permeate Storage, 15–20 gal 304L/316L SS (1/2 BBL Sanke) | Buffer storage for raw RO permeate; sized for peak-burst absorption + cycle hysteresis |
| 6 | Recirculation / Transfer Pump (P-102) — Grundfos CRN1S-4 A-FGJ-A-E-HQQE (washdown), 60 Hz VFD-controlled, runs continuously | Circulate T-101 water through UV; redirect to ice machine or treatment path on demand |
| 7 | UV Disinfection Unit — Pulsar PUV-200-20, in recirculation loop | Continuous biological disinfection of T-101 stored water |
| 8 | Post-UV Solenoid Manifold — SV-RECIRC / SV-ICE / SV-TREAT | Route UV-treated water: recirculate to T-101, supply ice machine, or send to mineral injection |
| 9 | Mineral Injection — 3 × Grundfos DDC 6-10 metering pumps (when SV-TREAT open) | Add select minerals per active HMI recipe to control final product TDS |
| 10 | Static Mixer — Koflo 105955Q34R in-line PVC mixer | Homogenise injected mineral streams into carrier water before T-102 / CT-103 |
| 11 | Tank 2 (T-102) — Treated Water Storage, ~ 5 gal 304L/316L SS (tall/narrow, sixtel keg) | Buffer storage for fully treated product water; fast recipe transitions |
| 12 | Distribution Pump (P-103) — ½ HP class, 60 Hz VFD-controlled (not yet procured) | Supply pressurised product water to espresso machine and drinking water |
| 13 | Points of Use | Espresso machine, drinking water filling station |
2. Design Basis & Performance Requirements
2.1 Feed Water Conditions
| Parameter | Design Value | Notes |
|---|---|---|
| Feed Water Source | Municipal potable supply | Chlorinated; dechlorinated by carbon filter |
| Feed Pressure | 40–80 psi (2.8–5.5 bar) | Minimum 30 psi at inlet required |
| Feed Temperature | 50–77 °F (10–25 °C) | Optimum for XLE Pro-2540 element |
| Feed TDS | Up to 500 mg/L (ppm) | Design maximum; consult supplier if higher |
| SDI | < 5 (after pre-filtration) | Required per Filmtec membrane guidelines |
2.2 System Performance Targets
| Parameter | Requirement | Measurement Method |
|---|---|---|
| RO Recovery Rate | Adjustable 50–75 % (nominal 65 %) | Q_perm / Q_feed × 100 % — calculated by PLC |
| Salt / TDS Rejection | ≥ 97 % (XLE membrane rated ≥ 99 %) | (1 − C_perm / C_feed) × 100 % — displayed on HMI |
| Permeate Flow Rate | Approx. 0.5–1.5 gpm (varies with pressure & temp) | Measured by permeate flow meter (FT-102) |
| Tank 1 Capacity (T-101) | 15–20 US gallons (tall/narrow form factor) | HDPE or 304L/316L SS; NSF 61 listed |
| Tank 2 Capacity (T-102) | 5 US gallons (tall/narrow form factor) | HDPE or 304L/316L SS; NSF 61 listed |
| Product Water TDS | Programmable setpoint per HMI recipe preset | Controlled by mineral injection pumps; verified by CT-103 |
| UV Dose | ≥ 16 mJ/cm² (USEPA potability minimum) cleared with ≈ 7× margin throughout lamp life. The Pulsar PUV-200-20 is rated by its manufacturer at 39 GPM @ 16 mJ/cm², 21 GPM @ 30 mJ/cm², and 16 GPM @ 40 mJ/cm², all at 95 % UVT. Operated in this design at the 4 GPM recirculation flow, dose scales inversely to ≈ 158 mJ/cm² fresh-lamp and ≈ 111 mJ/cm² at 9 000-hr end-of-lamp-life — ≈ 10× and 7× the USEPA minimum, respectively, and ≈ 4× and 2.8× the NSF/ANSI 55 Class A reference dose. See §3.5 for the full calculation. | Pulsar PUV-200-20 in T-101 recirculation loop |
2.3 Application & Consumption Basis
The system is sized for a specialty coffee shop with the following primary equipment and daily consumption:
Espresso Machine — SanRemo Cafe Racer:
| Boiler | Volume |
|---|---|
| Pre-heating boiler | 1 L |
| Steam boiler | 8 L |
| Group head boilers (× 2) | 2 × 1 L = 2 L |
| Total machine fill volume | 11 L ≈ 2.9 US gal |
Daily Water Consumption Estimate (100 cups/day × 8 oz):
| Category | Estimate | Source Tank |
|---|---|---|
| Coffee extraction water | ~6.25 gal (800 oz) | T-102 via P-103 |
| Steam losses, hot water draws | ~1–2 gal | T-102 via P-103 |
| Backflushing / cleaning cycles | ~0.5 gal | T-102 via P-103 |
| Espresso machine subtotal | ~8–9 gal/day | T-102 |
| Drinking water filling station | ~5–10 gal/day | T-102 via P-103 |
| Total T-102 demand | ~13–19 gal/day | |
| Ice machine | ~20–40 gal/day (model dependent) | T-101 direct (via SV-ICE) |
| Total T-101 demand | ~33–59 gal/day |
Sizing rationale:
- T-102 at 5 gallons turns over 3–4× per day at typical demand (~13–19 gal/day), keeping product water fresh and enabling fast recipe transitions — a recipe change fully propagates in 1–2 fill cycles (~10–15 min) instead of most of a day. At peak draw (~1–1.25 gal/hr), 5 gallons provides 4–5 hours of buffer. The worst-case single draw is a cold fill of the Cafe Racer boilers (2.9 gal), which P-102 refills in under a minute at 4 gpm. A tall, narrow tank form factor is preferred to give adequate vertical travel for level sensing.
- Metering pump compatibility: At 4 gpm transfer rate, a 5-gallon fill takes ~75 seconds. The DDC 6-10 metering pumps (100 mL/min max) operate at 7–12% of capacity for typical recipes — well within stable dosing range. For very low dosing rates, the PLC can slow P-102 via VFD-102 during fill cycles to extend dosing time.
- T-101 at 15–20 gallons is sized for peak-hourly demand bursts, not full-day storage. RO permeate output (0.5–1.5 gpm = 30–90 gph) outpaces peak demand (~10–15 gph) by 2–6×, so the membrane never falls behind. With a useful working range of ~70% of capacity (~10–14 gal between low-start and high-stop setpoints), T-101 cycles P-101 only 3–5× per day with 7–28 minute run windows — well clear of any thrashing regime that would shorten membrane life.
- T-101 worst-case concurrent demand — ice machine fill (~5 gal) plus T-102 fill (~5 gal) firing simultaneously totals ~10 gal. A 20-gal tank handles this with ~4 gal margin; a 15.5-gal tank (1/2 BBL Sanke keg form factor) relies on the cascade interlock in §5.6 (SV-TREAT inhibited if T-101 is low) to defer T-102 fill so ice demand is always served. Both options are acceptable.
- T-101 form factor benefits — a 16" diameter × ~23" tall cylinder (custom 20-gal build) or a 1/2 BBL Sanke keg (16.125" × 23.3", 15.5 gal) gives ~250 lb less water weight on the skid vs. a 50-gal design, faster water turnover (~9–12 hr avg residence vs. ~30 hr) for fresher water even with continuous UV, and an off-the-shelf 1/2 BBL keg conversion path for cost-effective sourcing.
3. Equipment Specifications
3.1 Pre-Filtration
Both pre-filter cartridges use identical 4.5″ × 20″ housings for spares commonality and simpler maintenance.
| Item | Specification |
|---|---|
| Sediment & Carbon Filter Housing (× 2) | US Water Systems 645-PWSSH-120 — 304 stainless, 4.5″ × 20″ DOE (Double Open End), 1″ NPT inlet/outlet, ring-nut closure, EPDM O-ring, ¼″ drain port, includes mounting bracket; rated up to 300 psi; FDA-compliant |
| Sediment Filter Cartridge | US Water Systems 550-USWPF-4520-05 — 4.5″ × 20″ pleated, 5 µm, NSF-listed for drinking water |
| Carbon Filter Cartridge | US Water Systems 507-USWCB-4520-10 — 4.5″ × 20″ coconut-shell carbon block, 10 µm, ≥ 95 % chlorine reduction, 32 000-gal capacity at 6 gpm, 250 psi operating pressure, 40–125 °F |
| Connections | 1″ NPT inlet/outlet; food-grade O-rings (EPDM or NSF-grade Buna-N) |
| Pressure Rating | 300 psi working pressure (housing); 250 psi (carbon cartridge — system limit) |
3.2 RO Membrane Assembly
| Item | Specification |
|---|---|
| Membrane Element | Filmtec XLE Pro-2540 or equal; low-energy brackish RO element |
| Format | 2540 (2.5″ diameter × 40″ length) |
| Rejection Rate | ≥ 99.0 % NaCl (manufacturer rated) |
| Permeate Flow | 50 GPD nominal at standard test conditions (77 °F, 150 psi, 250 ppm NaCl, 15 % recovery) |
| Membrane Housing | US Water Systems 257-208238 — 2540 stainless pressure vessel; ⅜″ FNPT connections; rated up to 300 psi |
| Mounting Brackets | Piping Now WPVCT-25 (qty 2) — 2.5″ vessel mounting clips |
| O-Rings / Brine Seals | NSF/ANSI 61 compliant; EPDM food grade |
| Operating Pressure | 100–250 psi (6.9–17.2 bar) adjustable via VFD pump speed |
3.3 Product Water Storage Tanks
Tank 1 — T-101: RO Permeate Storage
| Item | Specification |
|---|---|
| Capacity | 15–20 US gallons (target 20 gal; 15.5 gal acceptable for 1/2 BBL Sanke keg form factor) |
| Form Factor | Tall, narrow — ~16" diameter × ~23" tall (1/2 BBL Sanke keg dimensions: 16.125" × 23.3") or similar aspect ratio (~1.5–2:1 H:D). Provides adequate vertical travel for high/low float switches and minimizes skid footprint and water weight. |
| Material | HDPE (NSF/ANSI 61 listed) or 304L/316L stainless steel with sanitary finish; electropolished interior preferred for display visibility |
| Purpose | Buffer storage for raw RO permeate; continuously UV-disinfected via recirculation loop; supplies ice machine directly and treatment path to T-102. Sized for peak-burst absorption + RO cycle hysteresis (3–5 cycles/day expected), not full-day storage. |
| Connections | Inlet (from RO permeate), outlet (to P-102 suction), recirculation return (from SV-RECIRC), high-level sensor port, low-level sensor port, drain, vent (with air-gap or sanitary vent cap) |
| Pressure | Atmospheric / open vented |
| Compliance | NSF/ANSI 61 certified for potable water contact |
| Sourcing path | Preferred: modified 1/2 BBL Sanke keg (304 SS, debranded, ~$80) with sanitary tri-clamp ferrules welded for 5–6 ports + electropolish. Alternative: used brewery brite tank or custom 20-gal sanitary build. See tanks. |
Tank 2 — T-102: Treated Water Storage
| Item | Specification |
|---|---|
| Capacity | 5 US gallons |
| Form Factor | Tall, narrow — ~8″ diameter × ~24″ tall (1/6 BBL Sanke keg dimensions: 9.25" × 23.3", ~3:1 aspect) to provide adequate vertical travel for continuous level sensor and to keep dead volume low at the bottom |
| Material | HDPE (NSF/ANSI 61 listed) or 304L/316L stainless steel with sanitary finish; electropolished interior preferred for display visibility |
| Purpose | Buffer storage for fully treated product water (UV-disinfected, mineral-injected) ready for distribution to espresso machine and drinking water station. Small volume chosen for fast recipe transitions (1–2 fill cycles) and high turnover (3–4×/day). |
| Level Sensing | Continuous 4–20 mA level transmitter (see §4, LT-102) — preferred over discrete float switches due to small tank height; provides proportional fill level to PLC for smarter fill control and accurate volume tracking |
| Connections | Inlet (from mineral injection manifold), outlet (to P-103 suction), level transmitter port (top-mount), drain, vent (with air-gap or sanitary vent cap) |
| Pressure | Atmospheric / open vented |
| Compliance | NSF/ANSI 61 certified for potable water contact |
| Sourcing path | Preferred: modified 1/6 BBL Sanke keg (304 SS, debranded, ~$80) with 4 sanitary tri-clamp ferrules welded + electropolish. Alternative: small custom sanitary build. See tanks. |
3.4 Pump Specifications
CRITICAL: All pump motors must be rated for 60 Hz operation. The system uses 240 V single-phase power input to VFDs which output variable-frequency 3-phase power to drive the pump motors.
Pump P-101 — RO High-Pressure Feed Pump
| Parameter | Requirement |
|---|---|
| Manufacturer / Model (procured) | Grundfos CRN1S-15 A-FGJ-G-E-HQQE |
| Pump Type | Vertical multistage centrifugal; close-coupled |
| Rated Power | Per nameplate (size VFD-101 to motor FLA; design basis was ¾ HP class) |
| Motor Type | 3-Phase induction motor; 208-230/460 VAC |
| Frequency | 60 Hz (MANDATORY — do not supply 50 Hz motor) |
| Speed | 3,450–3,500 RPM at 60 Hz |
| Full-Load Current | Per nameplate at 230 V 3-phase |
| Design Duty Point | 110 psi (253 ft head) @ 4 gpm (RO operating target; verify against pump curve) |
| Wetted Materials | 316 stainless steel impellers, diffusers & shaft; EPDM O-rings |
| Shaft Seal | HQQE mechanical seal; food-grade elastomers |
| Connections | 1-¼″ Victaulic or NPT; mating fittings to be supplied |
| Speed Control | Controlled via VFD-101 (GS21-21P0); 0–100 % speed via Modbus RTU from PLC |
| Standards | NSF/ANSI 61; CE; cULus |
Pump P-102 — Recirculation / Transfer Pump (T-101 UV Loop + Transfer to T-102 + Ice Supply)
| Parameter | Requirement |
|---|---|
| Manufacturer / Model (procured) | Grundfos CRN1S-4 A-FGJ-A-E-HQQE |
| Pump Type | Vertical multistage centrifugal; close-coupled |
| Rated Power | ½ HP (0.37 kW) @ 3,500 rpm |
| Enclosure | Washdown-rated |
| Motor Type | 3-Phase induction motor; 208-230/460 VAC |
| Frequency | 60 Hz (MANDATORY — do not supply 50 Hz motor) |
| Speed | 3,500 rpm at 60 Hz (as-rated) |
| Full-Load Current | Per nameplate at 230 V 3-phase |
| Rated performance (nameplate) | 4.84 US gpm @ 77 ft TDH |
| Design Duty Point | 30 psi (69 ft head) @ 4 gpm (system target; verify against pump curve) |
| Wetted Materials | 316 stainless steel impellers, diffusers & shaft; EPDM O-rings |
| Shaft Seal | HQQE mechanical seal; food-grade elastomers |
| Connections | 1-¼″ Victaulic or NPT; mating fittings to be supplied |
| Speed Control | Controlled via VFD-102 (GS21-20P5); 0–100 % speed via Modbus RTU from PLC |
| Standards | NSF/ANSI 61; CE; cULus |
| Operating Mode | Runs continuously. Default state: recirculates T-101 water through UV via SV-RECIRC (normally open). PLC opens SV-TREAT to fill T-102 on demand or SV-ICE to supply ice machine on demand. |
Pump P-103 — Product Water Distribution Pump (T-102 → Espresso Machine & Drinking Water)
| Parameter | Requirement |
|---|---|
| Procurement | Not yet purchased — select and record model here when procured |
| Manufacturer / Model | Grundfos CRN1S-8 or equivalent 3-phase variant (design baseline) |
| Pump Type | Vertical multistage centrifugal; close-coupled |
| Rated Power | ½ HP (0.37 kW) |
| Motor Type | 3-Phase induction motor; 208-230/460 VAC |
| Frequency | 60 Hz (MANDATORY — do not supply 50 Hz motor) |
| Speed | 3,450–3,500 RPM at 60 Hz |
| Full-Load Current | 3.2 A at 230 V 3-phase (typical for ½ HP class — confirm on nameplate) |
| Design Duty Point | 50 psi (115 ft head) @ 3 gpm |
| Wetted Materials | 316 stainless steel impellers, diffusers & shaft; EPDM O-rings |
| Shaft Seal | HQQE mechanical seal; food-grade elastomers |
| Connections | 1-¼″ Victaulic or NPT; mating fittings to be supplied |
| Speed Control | Controlled via VFD-103 (GS21-20P5); 0–100 % speed via Modbus RTU from PLC |
| Standards | NSF/ANSI 61; CE; cULus |
| Notes | Supplies pressurised treated water from T-102 to espresso machine (SanRemo Cafe Racer) and drinking water filling station. VFD maintains constant-pressure setpoint on distribution header (feedback from PT-104). P-102 is procured as CRN1S-4; P-103 may differ — document exact model when purchased. |
3.5 UV Disinfection Unit
| Item | Specification |
|---|---|
| Manufacturer / Model (procured) | Pulsar PUV-200-20 (full SKU 405-PUV-200-20). The "200" prefix is the controller series (full-color LCD ballast, no UV-intensity sensor); the "-20" suffix is the lamp/flow class — the 20 GPM rating tier in the PUV-200 family, which spans -10 / -15 / -20 lamp options on the same controller. Procured OEM-Pulsar-branded (not the US Water Systems "-BGF" variant called out in earlier spec revisions). |
| Application | In-line; installed in the T-101 recirculation loop downstream of P-102 and upstream of the solenoid valve manifold (SV-RECIRC / SV-ICE / SV-TREAT). Runs continuously while P-102 is active — all water leaving T-101 passes through UV regardless of destination. |
| UV Dose (delivered, design basis) | USEPA potability target ≥ 16 mJ/cm² met with ≈ 7× margin throughout lamp service life. Design-point dose ≈ 158 mJ/cm² fresh / ≈ 111 mJ/cm² at 9 000-hr lamp EOL at the 4 GPM nominal recirculation flow — see calculation below. The procurement step-up from the previously-specified PUV-200-10 (≈ 44 / 31 mJ/cm² fresh / EOL at 4 GPM) to the larger PUV-200-20 reactor moves the unit from "comfortably above USEPA potability minimum" to "well above the NSF/ANSI 55 Class A reference dose throughout lamp life" — though the unit itself remains uncertified (see Compliance row). |
| Lamp | 42 W lamp / 51 W total system input (per Pulsar manual p. 22 spec table); 9 000-hour rated service life (≈ 1 year of continuous operation); replacement P/N 406-PUV-LM-20. |
| Quartz Sleeve | Replacement P/N 406-PUV-QS-20 (per manual p. 22); clean annually at minimum (RO permeate is essentially scale- and particle-free, so heavy fouling is not expected). |
| Reactor Chamber | 304 stainless steel, A249 pressure-rated tubing; 8.9 × 91.7 cm (3.5″ diameter × 36.1″ length) per manual p. 22; ASME pressure-vessel design. Note: reactor diameter is 3.5″ (vs 2.5″ on the previously-spec'd -10) — confirm skid clamps, mounting brackets, and clearance to neighbouring components accommodate the larger pipe before final layout. Reserve at least one full reactor length (~36″) of clear space at the lamp-connector end for sleeve and lamp removal. |
| Process Connections | 1″ MNPT inlet/outlet (per manual p. 22; up from ¾″ on the -10 — fittings into the recirc loop must be re-selected to match). |
| Operating Pressure | 0–150 psi (10 bar) maximum |
| Operating Water Temperature | 36–104 °F (2–40 °C) |
| Power Supply | 90–265 VAC, 50–60 Hz universal input, 51 W max (1 A max) (per manual p. 22), fed from a dedicated 120 VAC GFCI receptacle on the control panel via the supplied NEMA 5-15P cord-and-plug. Universal input means the unit will operate unchanged on any standard US 120 V branch circuit. (Slight uptick from the previously-specified -10 which drew 49 W — negligible vs. the §6 panel load calc.) |
| Mounting Orientation | Vertical preferred with inlet at the bottom (allows trapped air to purge); horizontal acceptable per the manufacturer. Reserve at least one full reactor length (~36″) of clear space at the lamp-connector end for sleeve and lamp removal. |
| Warranty (per manual p. 24) | 10-year limited warranty on the 304 SS reactor; 3-year on ballast/controller; 1-year on lamp, UV sensor, and quartz sleeve — all from date of original purchase or installation. Warranty void if water-quality limits exceeded (hardness > 7 gpg, iron > 0.3 ppm, manganese > 0.05 ppm, tannins > 0.1 ppm, turbidity > 1 NTU, UVT < 75 %); RO permeate trivially clears all of these by orders of magnitude. |
| Control | On/Off via PLC relay output; UV hour meter / lamp-life countdown is built into the controller (yellow caution at 30 days remaining → 7-day audible chirp → continuous alarm at expiry, with up to 3 × 7-day operator deferrals available); runs continuously during system operation |
| Compliance | CSA / CE compliant per nameplate (controller-family certifications; verify on the as-shipped unit). The Pulsar manual does not claim NSF/ANSI 61 certification for the unit, and the larger PUV-200-20 reactor is not NSF/ANSI 55 Class A validated either; the wetted reactor is 304 SS A249 (an inherently NSF-61-acceptable material), but the unit itself is not certified. Plan-check submittal will treat the UV unit under the same San Diego DEH MFF §IV.C "approval in the absence of ANSI sanitation certification" pathway used for the metering pumps (see Metering pumps §8) — submit the manufacturer's product literature, materials declaration (304 SS A249 chamber, FDA-grade quartz sleeve, EPDM/PTFE seals), and reactor pressure rating as documentary evidence. |
UV dose calculation — Pulsar PUV-200-20 at 4 GPM recirculation flow:
UV dose at fixed lamp output is inversely proportional to flow rate (longer residence time = more photons per millilitre of water):
dose_actual = dose_rated × (flow_rated / flow_actual)
The manufacturer's spec table (Pulsar manual p. 22) provides three rating points for the PUV-200-20 lamp/reactor — all at 95 % UVT, all defined by the same physical hardware — that act as independent cross-checks on the calculation:
| Manufacturer rating point | Calculated dose at 4 GPM (fresh lamp, 95 % UVT) |
|---|---|
| 16 mJ/cm² @ 39 GPM (USEPA minimum) | 16 × (39 / 4) ≈ 156 mJ/cm² |
| 30 mJ/cm² @ 21 GPM | 30 × (21 / 4) ≈ 158 mJ/cm² |
| 40 mJ/cm² @ 16 GPM (NSF/ANSI 55 Class A reference) | 40 × (16 / 4) = 160 mJ/cm² |
All three rating points converge on a fresh-lamp dose of ≈ 158 mJ/cm² at 4 GPM, giving a clean cross-check on the inverse-flow scaling. This is approximately 3.5× the dose the previously-spec'd PUV-200-10 would have delivered at the same flow (~44 mJ/cm²) — the design intent of the recirculation loop is unchanged, but the headroom to USEPA potability and to NSF/ANSI 55 Class A reference doses is dramatically larger. End-of-life behaviour and additional in-service margins:
- End-of-lamp-life derate — UV-C lamps end their service life at ≈ 70 % of new output, which is the convention that defines the 9 000-hour rating. End-of-life dose at 4 GPM: 158 × 0.70 ≈ 111 mJ/cm² — ≈ 7× the USEPA 16 mJ/cm² potability minimum, ≈ 3.7× the 30 mJ/cm² level commonly cited for high-confidence pathogen inactivation, and ≈ 2.8× the NSF/ANSI 55 Class A reference dose of 40 mJ/cm². The manufacturer's lamp-countdown alarm (see Control row above) ensures the lamp is replaced before output drifts further.
- UVT margin — the manufacturer's ratings assume 95 % UVT. RO permeate is essentially particle-free with UV transmittance typically > 98 %, providing additional unaccounted margin in service.
- Cumulative recirculation — even setting per-pass dose aside, the same parcel of water in T-101 returns through UV every 30–60 minutes in normal operation, so cumulative dose on stored water is effectively unbounded.
Operational implication for VFD-102 control: the design-point dose of 158 mJ/cm² fresh / 111 mJ/cm² EOL is computed at the 4 GPM nominal recirculation flow; the PLC should hold VFD-102 at this setpoint during normal recirculation. The pump's full rated capacity is 4.84 GPM @ 77 ft TDH (per §3.4); operating briefly at the pump's full rated capacity during transfer or ice-supply demand reduces dose proportionally (e.g. ≈ 130 mJ/cm² fresh / ≈ 91 mJ/cm² EOL at 4.84 GPM) — both still well above any regulatory or design threshold. With this much per-pass dose headroom, even an order-of-magnitude flow excursion would still clear the USEPA potability minimum, so the recirculation loop is no longer flow-limited from a UV perspective.
Compliance framing: the system clears the USEPA 16 mJ/cm² potability target with ≈ 7× margin throughout the full lamp service life and exceeds the 40 mJ/cm² NSF/ANSI 55 Class A reference dose by ≥ 2.8× at end of lamp life — both well in excess of any regulatory or commonly-cited microbiological-treatment threshold under the NSF/ANSI 61 + CalCode + SD DEH framework cited in §8. The unit itself is not NSF/ANSI 55 Class A validated equipment regardless of delivered dose — Class A is a unit-level type-test program, not a dose threshold — so the system should not be represented as Class A-certified. If a jurisdiction or insurance carrier later demands explicit Class A certification, that requires substituting a NSF/ANSI 55 Class A-validated UV unit; the recirculation loop architecture and dose math here remain unchanged, only the unit and certification paperwork differ.
Post-fault disinfection: per the Pulsar manual's hard-alarm procedure (lamp failure or low-UV alarm on a monitored unit), any standing water in T-101 that may have passed during the alarm condition must be presumed potentially contaminated. The PLC alarm-handling routine in §5.6 must (a) close SV-TREAT and SV-ICE on UV fault, (b) annunciate the fault on the HMI, and (c) require operator-acknowledged disinfection of T-101 + downstream piping (drain, chlorine flush per the manual's System Disinfection procedure, rinse) before normal operation can resume.
3.6 Automated Ball Valve (Feed Water Inlet)
| Item | Specification |
|---|---|
| Type | Full-bore automated ball valve; electric actuator with spring-return (fail-closed) |
| Actuation | 24 VDC electric; 2-wire; spring-return to CLOSED position on power loss |
| Body Material | 316 stainless steel or food-grade brass |
| Seat / Seal | PTFE seat; EPDM or PTFE stem seals; food-grade |
| Control | On/Off via PLC relay output (P2-08TRS) |
| Compliance | NSF/ANSI 61 listed for potable water service |
3.7 Post-UV Solenoid Valve Manifold
Three solenoid valves are installed in a manifold immediately downstream of the UV unit. The PLC controls these valves to route UV-treated water from T-101 to the appropriate destination.
| Tag | Function | Normal State | Fail State | Notes |
|---|---|---|---|---|
| SV-RECIRC | Return UV-treated water to T-101 | Normally Open | Open (safe — water recirculates to tank) | Default path; closes when SV-ICE or SV-TREAT opens to direct full flow to demand path |
| SV-ICE | Supply UV-treated permeate to ice machine | Normally Closed | Closed (safe) | Opens on ice machine demand signal (FS-101); no mineral injection — ice machine receives pure RO permeate |
| SV-TREAT | Route water to mineral injection → T-102 | Normally Closed | Closed (safe) | Opens when T-102 level is below setpoint; water passes through metering pumps before entering T-102 |
Solenoid Valve Specifications (all three):
| Item | Specification |
|---|---|
| Type | 2-way, direct-acting or pilot-operated solenoid valve |
| Body Material | 316 stainless steel or food-grade brass |
| Seat / Seal | PTFE seat; EPDM or PTFE seals; food-grade |
| Size | ¾″ or 1″ NPT to match process piping |
| Actuation | 24 VDC coil; DIN connector |
| Response Time | < 500 ms open/close |
| Pressure Rating | ≥ 100 psi |
| Control | On/Off via PLC relay output (P2-08TRS #2) |
| Compliance | NSF/ANSI 61 listed for potable water service |
3.8 Mineral Injection Metering Pumps (× 3)
| Item | Specification |
|---|---|
| Quantity | 3 pumps (Mineral A, Mineral B, Mineral C) |
| Manufacturer / Model (procured) | Grundfos DDC 6-10 AR-PVC/V/C-F-31 — order code 001FG (× 3) |
| Type | Diaphragm metering pump (dosing) |
| Max pressure | 150 psi |
| Rated output | 6 L/h (1.5 US gph) |
| Power | 22 W |
| Wetted materials | PVC liquid end; PTFE diaphragm; elastomers per Grundfos datasheet — acceptable food-contact plastics for dilute mineral concentrates |
| NSF/ANSI 61 | Catalog-level: yes; nameplate: no. The Grundfos product catalog for Product No 98586903 lists this exact model as approved to CE · CSA-US · NSF/ANSI 61 · EAC · RCM — NSF 61 is a manufacturer-claimed approval at the model level. The procured units (Made in France, EU production run) have nameplates carrying CE, CSA-US, EAC, RCM (reg N20693) plus China RoHS / WEEE pictograms; NSF 61 is not stamped on these specific plates (regional marking practice — Grundfos does not redundantly mark NSF 61 on EU-built units). Permitting: Submit (a) Grundfos catalog page for 98586903 (model-level NSF 61 evidence), (b) nameplate photos of all three units, (c) materials declaration (PVC head / PTFE diaphragm / ceramic balls / FKM gaskets), under San Diego DEH MFF §IV.C — "In the absence of applicable ANSI sanitation certification, the equipment design, construction and installation is subject to approval by this Department." See Metering pumps §8 for the full submittal package. |
| Turndown | Must support stable dosing below 5 mL/min (verify against DDC curve at operating pressure) |
| Pressure Rating | 150 psi maximum (per model); system operating point must be within pump capability |
| Power supply | 100–240 VAC, 50–60 Hz; controllable via PLC relay output (on/off dry-contact) |
| Adjustment | Digital control; onboard display per DDC series |
| Application | Inject minerals into water stream between SV-TREAT and T-102 inlet; dosing rate set by active HMI recipe preset |
| Alternates (reference only) | ProMinent Gamma X, Iwaki, LMI/Milton Roy PD series, Walchem — if spare needed |
Static Mixer (downstream of injection points, upstream of T-102):
| Item | Specification |
|---|---|
| Manufacturer / Model | Koflo 105955Q34R |
| Type | In-line PVC static mixer |
| Connection | ½″ MNPT |
| Function | Homogenises the three injected mineral streams into the carrier water before T-102 so that the CT-103 reading downstream of the mixer reflects a representative final-blend TDS rather than a near-injection-point spike. |
| Pressure Drop | Low ΔP at design flow |
Standard Mineral Concentrates:
| Pump | Mineral Concentrate | Role in Coffee Water Profile |
|---|---|---|
| Mineral A | Magnesium sulfate (MgSO₄) | Extraction enhancer; brightness and clarity |
| Mineral B | Calcium chloride (CaCl₂) | Body and mouthfeel; total hardness |
| Mineral C | Sodium bicarbonate (NaHCO₃) | Buffer capacity / alkalinity; balance and sweetness |
4. Instrumentation & Sensors
| Tag | Device | Range / Output | Location | Notes |
|---|---|---|---|---|
| PT-101 | Pressure Transmitter | 0–300 psi; 0.5–4.5 VDC | Feed water inlet | Dataq #2000361-300H or equal; 316SS wetted; ⅛″ NPT |
| PT-102 | Pressure Transmitter | 0–300 psi; 0.5–4.5 VDC | RO feed (high-pressure side) | Pre-membrane; monitors pump output pressure |
| PT-103 | Pressure Transmitter | 0–300 psi; 0.5–4.5 VDC | RO permeate outlet | Monitors membrane performance; low side |
| PT-104 | Pressure Transmitter | 0–300 psi; 0.5–4.5 VDC | P-103 discharge / distribution header | Feedback for constant-pressure VFD control |
| FT-101 | Flow Meter — Feed | Pulse output; 5–24 VDC | Feed line to RO | Used for recovery calculation; paddle or mag type |
| FT-102 | Flow Meter — Permeate | Pulse output; 5–24 VDC | Permeate to T-101 | Used for recovery calculation |
| FT-103 | Flow Meter — Distribution | Pulse output; 5–24 VDC | P-103 discharge to POUs | Monitors distribution flow to espresso machine / drinking water |
| CT-101 | Conductivity Sensor — Hanna HI7635 | 0–3 999 µS/cm; 4–20 mA | Feed water | PP body, 1″ NPT inline flow cell; NTC temperature compensation; for feed TDS + salt-rejection calculation |
| CT-102 | Conductivity Sensor — Levtech HMCCS | 0–1 000 µS/cm; 4–20 mA | Permeate outlet (before T-101) | 316L SS, ¾″ MNPT; permeate TDS; used for salt-rejection calculation |
| CT-103 | Conductivity Sensor — Levtech HMCCS | 0–1 000 µS/cm; 4–20 mA | T-102 inlet (after mineral injection) | 316L SS, ¾″ MNPT; verifies final TDS matches active recipe setpoint |
| TT-101 | RTD Temperature Probe | Pt100 or Pt1000; 3/4-wire | Feed or permeate | Temperature compensation for conductivity & flow |
| LSH-101 | Level Switch — High | Dry contact (N.O.); 24 VDC | T-101 (RO Permeate Tank) | High level → stop RO feed pump (P-101) |
| LSL-101 | Level Switch — Low | Dry contact (N.O.); 24 VDC | T-101 (RO Permeate Tank) | Low level → stop recirculation/transfer pump (P-102); alarm |
| LT-102 | Continuous Level Transmitter | 4–20 mA (0–100 % level) | T-102 (Treated Water Tank) | Replaces discrete float switches on T-102 (5-gal tall/narrow tank); ultrasonic or capacitive; top-mount; PLC derives high, low, and fill setpoints from continuous signal; provides proportional fill level for smarter control and volume tracking |
| FS-101 | Flow / Demand Switch | Dry contact (N.O.); 24 VDC | Ice machine supply branch | Detects ice machine water demand; PLC opens SV-ICE when active |
All instrumentation in contact with product water shall be rated NSF/ANSI 61. Sensor connections to the PLC are via the Automation Direct P2-16ND3 (digital), P2-08AD-2 (analog 0–10 VDC), and P2-06RTD (RTD) I/O modules. The LT-102 continuous level transmitter (4–20 mA) connects to P2-08AD-2.
5. Control System
5.1 PLC — Automation Direct Productivity2000
| Item | Specification |
|---|---|
| CPU | AutomationDirect P2-550 Productivity2000 |
| Base / Rack | P2-11B — 11-slot base (CPU + 5 I/O modules populated; 5 slots open for future expansion). The original spec called for a P2-08B (8-slot, CPU + 7 I/O) but no P2-08B was available on the used market when procurement happened, so the 11-slot variant was substituted. The 11-slot base is electrically and functionally identical for the populated modules and adds extra expansion headroom. |
| AC Power Module | P2-01AC — backplane-side AC supply (mounts to left of base, no slot used); 100–240 VAC 50/60 Hz input |
| Programming | Free Productivity Suite IDE (ladder, function block, structured text) |
| Communications | Dual Ethernet (RJ45); RS-485 Modbus RTU; RS-232; USB; microSD |
| VFD Interface | All three VFDs communicate via RS-485 Modbus RTU from PLC RS-485 port (daisy-chained) |
| HMI Interface | Ethernet (TCP/IP) to C-more HMI panel |
| Power | 12–24 VDC from panel-mounted DIN-rail power supply |
| Enclosure | NEMA 4 rated control panel; UL 508A listed enclosure recommended |
5.2 I/O Module Summary
5 I/O modules occupy 5 of the 10 I/O slots on the P2-11B base; 5 slots remain open for future expansion (the highest-priority expansion is a second P2-08AD-2, since the analog-input rail is already full).
| Module | Part Number | I/O Points Used | Spare Points |
|---|---|---|---|
| 16-pt 24 VDC Discrete Input | P2-16ND3-1 | 9 (2 level T-101, 3 flow pulse, 3 VFD status, 1 ice demand) | 7 |
| 8-pt Form-C Relay Output #1 | P2-08TRS | 8 (ball valve, UV, 3 metering pumps, 3 VFD run/stop) | 0 |
| 8-pt Form-C Relay Output #2 | P2-08TRS | 3 (SV-RECIRC, SV-ICE, SV-TREAT) | 5 |
| 8-ch Analog Input (0–10 VDC / 4–20 mA) | P2-08AD-2 | 8 (4 pressure, 3 conductivity, 1 level LT-102) | 0 ★ FULL |
| 6-ch RTD Input (Pt100/Pt1000) | P2-06RTD | 1 (feed/permeate temperature) | 5 |
Each module is wired to field terminals through a P2-RTB 18-pin removable terminal block (qty 4 stocked).
5.3 Variable Frequency Drives
IMPORTANT: All three drives accept 200–240 VAC single-phase input (standard US 240 V service). No 3-phase utility supply is required. Motors must be 60 Hz rated.
| Parameter | VFD-101 (RO Feed Pump) | VFD-102 (Recirc/Transfer Pump) | VFD-103 (Distribution Pump) |
|---|---|---|---|
| AutomationDirect Part No. | GS21-21P0 | GS21-20P5 | GS21-20P5 |
| Rated HP | 1 HP (drives ¾ HP motor) | ½ HP (drives ½ HP motor) | ½ HP (drives ½ HP motor) |
| Input Voltage | 200–240 VAC, 1-phase | 200–240 VAC, 1-phase | 200–240 VAC, 1-phase |
| Input Frequency | 60 Hz | 60 Hz | 60 Hz |
| Rated Input Current | 10.8 A (CT) / 11.3 A (VT) | 7.3 A (CT) / 8.3 A (VT) | 7.3 A (CT) / 8.3 A (VT) |
| Output | 0–230 VAC, 3-phase, variable freq. | 0–230 VAC, 3-phase, variable freq. | 0–230 VAC, 3-phase, variable freq. |
| Control Interface | RS-485 Modbus RTU from P2-550 | RS-485 Modbus RTU from P2-550 | RS-485 Modbus RTU from P2-550 |
| Speed Control | 0–100 % via PLC setpoint (Modbus) | 0–100 % via PLC setpoint (Modbus) | 0–100 % via PLC setpoint (Modbus) |
| Protections | Motor overload, over/under voltage, over-temp, short circuit | Motor overload, over/under voltage, over-temp, short circuit | Motor overload, over/under voltage, over-temp, short circuit |
| Config Software | GSoft2 (Free — AutomationDirect) | GSoft2 (Free — AutomationDirect) | GSoft2 (Free — AutomationDirect) |
5.4 HMI Display
| Item | Specification |
|---|---|
| Model | AutomationDirect C-more CM5-T10W (newer CM5 series; replaces the originally-spec'd EA9-T10WCL) |
| Display | 10.1″ widescreen colour TFT LCD; 1024 × 600 WSVGA; LED backlight |
| Touch | Resistive single-touch; industrial-grade |
| Enclosure Rating | NEMA 4/4X (IP65); suitable for wet / washdown environments |
| Interface | (2) Ethernet to P2-550 PLC; (3) serial (RS-232/485); (4) USB; (1) SD card slot |
| Power | 12–24 VDC |
| Programming | Free CM5 Series Software v8.0 (replaces C-more EA9 Designer for the CM5 platform) |
| Key Displays | Feed pressure, RO feed pressure, permeate pressure, distribution pressure, feed flow, permeate flow, distribution flow, feed conductivity, permeate conductivity, treated water conductivity (actual vs. recipe target), temperature, RO Recovery %, Salt Rejection %, T-101 level status, T-102 level status, VFD-101/102/103 speed, solenoid valve states, active water recipe name and parameters, system alarms |
5.5 HMI Water Recipe Management
The HMI shall provide a dedicated recipe management screen allowing the operator to create, edit, select, and activate water mineral profiles for the espresso machine.
Recipe System Requirements:
| Item | Specification |
|---|---|
| Recipe Storage | Minimum 10 named presets stored in HMI non-volatile memory |
| Parameters per Recipe | Mineral A dosing rate (mL/gal), Mineral B dosing rate (mL/gal), Mineral C dosing rate (mL/gal), target TDS (ppm) |
| Active Recipe | One recipe active at a time; displayed on main HMI screen |
| Recipe Selection | Operator selects from named preset list on HMI touchscreen |
| Feedback | CT-103 actual TDS displayed alongside recipe target TDS; deviation alarm if actual exceeds ± tolerance band |
| Recipe Change Behaviour | On recipe change, PLC applies new dosing rates on the next T-102 fill cycle; HMI displays estimated fill cycles to fully transition T-102 to new recipe |
Example Factory-Loaded Presets:
| Preset Name | Mineral A (MgSO₄) | Mineral B (CaCl₂) | Mineral C (NaHCO₃) | Target TDS |
|---|---|---|---|---|
| SCA Gold Cup | 2.4 mL/gal | 3.1 mL/gal | 1.8 mL/gal | ~120 ppm |
| Light Roast — High Extraction | 3.6 mL/gal | 1.5 mL/gal | 2.0 mL/gal | ~100 ppm |
| Medium Roast — Balanced | 2.0 mL/gal | 2.5 mL/gal | 2.2 mL/gal | ~130 ppm |
| Rao/Perger Water | 3.0 mL/gal | 0.0 mL/gal | 1.5 mL/gal | ~85 ppm |
| Custom 1 | (user-defined) | (user-defined) | (user-defined) | (user-defined) |
Note: Dosing rates shown are illustrative and depend on mineral concentrate strength. Actual rates must be calibrated during commissioning using laboratory-verified TDS measurements. The system starts with RO permeate at near-zero TDS, so mineral addition is fully additive with no feed water variability.
5.6 PLC Control Logic Summary
The PLC shall implement the following control functions as a minimum:
Start/Stop & Sequencing:
- Automatic start/stop sequencing: pre-fill, production, recirculation, transfer, distribution, flush, and standby modes
- Automated ball valve control: open on system start; close on shutdown or fault
VFD Speed Control:
- VFD-101 (P-101): ramp-up on start; pressure setpoint PID control for RO feed pump
- VFD-102 (P-102): runs continuously; maintains recirculation flow setpoint; PLC may adjust speed when redirecting flow to ice machine or treatment path
- VFD-103 (P-103): constant-pressure PID control on distribution header (feedback from PT-104)
UV Recirculation Loop:
- UV lamp runs continuously while P-102 is active (effectively continuous during system operation)
- Default valve state: SV-RECIRC open, SV-ICE closed, SV-TREAT closed — water recirculates through UV and returns to T-101
- T-101 full volume circulates through UV approximately every 30–60 minutes at P-102 operating flow rate
Solenoid Valve Manifold Control:
- SV-RECIRC: default open; closes (partially or fully) when SV-ICE or SV-TREAT opens to direct flow to demand path
- SV-ICE: opens when FS-101 detects ice machine demand; closes when demand ceases; PLC inhibits if T-101 is at low level
- SV-TREAT: opens when T-102 level falls below fill setpoint and T-101 has adequate level; closes when T-102 reaches high level
Tank Level Management:
- T-101: start RO production (P-101) when level drops below low-set; stop P-101 on high level; if T-101 reaches critically low level, stop P-102 to protect pump
- T-102 (continuous level via LT-102): PLC reads 4–20 mA level signal and derives software setpoints — fill-start (e.g. 30 %), fill-stop / high (e.g. 90 %), low-alarm / stop P-103 (e.g. 10 %). Open SV-TREAT and enable metering pumps when level falls below fill-start; close SV-TREAT and stop metering pumps at fill-stop; stop P-103 on low-alarm. Continuous signal also enables HMI display of real-time T-102 fill percentage and estimated volume remaining.
- Cascade interlock: if T-101 is low AND T-102 is low, prioritise RO production (P-101); inhibit SV-TREAT until T-101 recovers above minimum threshold
Mineral Injection & Recipe Control:
- Active recipe selected via HMI determines metering pump dosing rates
- Metering pumps enabled only when SV-TREAT is open (water flowing to T-102)
- Dosing is ratio-based relative to transfer flow; PLC calculates pump speed/duty based on recipe mL/gal setpoint and measured flow
- CT-103 provides closed-loop TDS verification; alarm if actual TDS deviates from recipe target by more than configurable tolerance
Monitoring & Logging:
- Calculated display values: RO Recovery % and Salt Rejection % — updated every scan
- Alarm monitoring: high/low pressure, low flow, VFD fault, high conductivity, level faults on both tanks, UV lamp fault, TDS recipe deviation
- Data logging via SD card: key process variables at configurable interval
UV Fault Handling (per Pulsar manual hard-alarm procedure — see §3.5):
- On UV lamp fault (lamp out, lamp expired, or controller hard-alarm): immediately close SV-TREAT and SV-ICE; SV-RECIRC remains open so the tank does not deadhead the recirculation pump. P-101 (RO production) may continue, but no water leaves T-101 toward the ice machine or T-102 until the fault clears.
- HMI annunciates the UV fault and locks out auto-resume; operator acknowledgement is required to clear.
- Following any UV hard-alarm event, T-101 and all downstream piping/tanks shall be assumed potentially contaminated and must be disinfected per the Pulsar manual's System Disinfection procedure (drain, chlorine flush, rinse, return to service) before normal water service resumes. The HMI procedure screen shall present the disinfection checklist as part of the alarm-clearance workflow.
- The Pulsar controller's own lamp-life countdown (30-day caution → 7-day chirp → 0-day continuous alarm, with up to 3 × 7-day operator deferrals) shall be mirrored to the PLC via dry-contact wiring (or via the optional
406-PUV-MD-RAMremote-alarm module if installed) so the HMI can annunciate impending lamp replacement well before expiry.
6. Electrical Requirements
⚠ All electrical components must be rated and labelled for 60 Hz operation. Many imported motors and drives are 50 Hz–labelled; confirm 60 Hz compatibility on the nameplate for every motor, drive, solenoid, and transformer before purchase.
| Circuit | Description | Voltage | Current | Breaker | Wire Size |
|---|---|---|---|---|---|
| CB-1 | VFD-101 — RO Feed Pump (GS21-21P0) | 240 VAC | 10.8 A | 20 A 2-pole | 10 AWG |
| CB-2 | VFD-102 — Recirc/Transfer Pump (GS21-20P5) | 240 VAC | 7.3 A | 15 A 2-pole | 14 AWG |
| CB-3 | VFD-103 — Distribution Pump (GS21-20P5) | 240 VAC | 7.3 A | 15 A 2-pole | 14 AWG |
| CB-4 | Control Panel — PLC, HMI, 24 VDC PS, UV, metering pumps, solenoid valves | 120 VAC | ≤ 10 A | 20 A 1-pole | 12 AWG |
Additional electrical requirements:
- A lockable disconnect switch shall be provided within sight of each motor (NEC 430.102)
- VFD output wiring to motors shall use Southwire VFDC-16-4B-1 shielded VFD cable (16 AWG, 4-conductor including ground, XLPE insulation, TPE jacket) to minimise EMI interference with PLC analog inputs
- A line reactor shall be installed on the input side of each VFD: AutomationDirect LR2-21P0-1PH-A (1 HP, 11.6 A) on VFD-101; AutomationDirect LR2-20P5-1PH (½ HP, 6.2 A) on VFD-102 and VFD-103. Both LR2 series are 230 VAC, 1-phase, 3 % impedance, input-side only.
- All control panel wiring shall be in accordance with NEC Article 430 and UL 508A
- 24 VDC DIN-rail power supply: Mean Well NDR-120-24 (≥ 5 A) for field power to sensors, solenoid valves, ball valve actuator, and level switches. This is separate from the P2-01AC backplane supply that powers the PLC and I/O modules.
- Branch-circuit breakers (DIN-rail mount, AutomationDirect Gladiator series): GMCBU-2C-20 (CB-1, 20 A 2-pole), GMCBU-2C-15 (CB-2 / CB-3, 15 A 2-pole, qty 2), GMCBU-1C-20 (CB-4, 20 A 1-pole)
- All panel components shall be CE marked and UL listed where required
7. Materials of Construction & Sanitary Requirements
This system is intended for the production of drinking water for human consumption. All materials in contact with product water must be non-toxic, non-leaching, and compliant with applicable food-contact and drinking water standards.
| Component | Required Material | Standard |
|---|---|---|
| Pump bodies, impellers, shafts | 316L stainless steel | NSF/ANSI 61; FDA CFR 21 |
| O-rings and seals (pump / valve / fittings) | EPDM or NSF-grade Buna-N (Nitrile) | NSF/ANSI 61; FDA CFR 21 §177 |
| Membrane housing | Fibreglass-wound or 316SS | NSF/ANSI 58 or 61 |
| Filter housings | 316SS or food-grade polypropylene | NSF/ANSI 42 or 61 |
| Storage tanks (T-101 and T-102) | NSF-listed HDPE or 304L / 316L SS | NSF/ANSI 61 |
| Process tubing / piping | 316SS, HDPE, or NSF-listed CPVC / polypropylene | NSF/ANSI 61 |
| Fittings and valves | 316SS or brass (NSF listed); lead-free per Safe Drinking Water Act | NSF/ANSI 61; NSF/ANSI 372 (lead-free) |
| UV chamber | 304 SS A249 pressure-rated tubing (procured Pulsar PUV-200-20) | Material is inherently NSF-61-acceptable; unit is CSA / CE compliant per nameplate but does not carry NSF/ANSI 61 or NSF/ANSI 55 Class A certification — plan-check submittal under SD DEH MFF §IV.C, see §3.5 |
| Metering pump wetted parts | PVC dosing head, PTFE diaphragm, ceramic valve balls, FKM gaskets (procured DDC 6-10, type code PVC/V/C) | NSF/ANSI 61: model-level (Grundfos catalog for Product 98586903), not stamped on the procured EU-build nameplates (plate marks: CE / CSA-US / EAC / RCM). Plan-check per Metering pumps §8 / MFF §IV.C with catalog page as documentary evidence. |
| Ball valve body and seat | 316SS body; PTFE seat | NSF/ANSI 61 |
| Solenoid valve bodies and seals | 316SS or food-grade brass body; PTFE seat; EPDM seals | NSF/ANSI 61 |
Prohibited Materials:
- Lead-containing brass or solder in any water-contact fitting
- Galvanised steel — unacceptable for corrosion and contamination reasons
- Standard neoprene seals — use EPDM or PTFE only
8. Standards & Compliance
| Standard | Scope |
|---|---|
| NSF/ANSI 58 | Reverse osmosis drinking water treatment systems — system and component certification |
| NSF/ANSI 61 | Drinking water system components — materials in contact with drinking water |
| NSF/ANSI 55 Class A | UV microbiological water treatment systems — 40 mJ/cm² reference dose. Cited as a dose benchmark only — the procured Pulsar PUV-200-20 is not Class A-validated equipment (Class A is a unit-level type-test program, not a dose threshold; see §3.5). The system delivers ≈ 158 mJ/cm² fresh / ≈ 111 mJ/cm² EOL at the 4 GPM recirc flow — well above the 40 mJ/cm² Class A reference dose throughout lamp life — but Class A certification is not required for drinking-water service under the controlling SD DEH / CalCode framework. |
| NSF/ANSI 42 | Drinking water treatment units — aesthetic effects (chlorine/taste/odour reduction) |
| NSF/ANSI 372 | Lead-free designation for all fixtures and fittings |
| FDA CFR 21 | Food contact materials — applicable for all elastomers and plastics in product water contact |
| NEC Article 430 | Motor and motor circuit requirements (USA electrical code) |
| NEC Article 440 | Air-conditioning and refrigerating equipment (applicable to hermetic motor compressors if any) |
| UL 508A | Industrial control panels — listed enclosure required |
| CE Marking | Required for all electrical components shipped to USA for resale |
8.1 Local Enforcement (San Diego County)
This system will be inspected by the County of San Diego, Department of Environmental Health and Quality, Food and Housing Division. Two permitting paths are viable:
- Stationary (recommended): the skid is treated as equipment in an existing permanent food facility (the host dessert shop). Regulatory anchor: California Retail Food Code (CalCode), Cal. Health & Safety Code §113700 et seq., enforced via SD DEH plan-check for equipment additions. The host facility's existing handwashing, warewashing, water heater, and wastewater infrastructure is leveraged; no separate sinks/tanks are added for the skid itself.
- Mobile (deferred unless the business case requires it): the skid would be plan-checked and permitted as a Mobile Food Facility under the SD DEH Construction and Operational Guide for Mobile Food Facilities and Mobile Support Units (DEH-FH-991, Rev 04/30/2021), which adds requirements for dedicated handwash + warewash sinks, water heater, wastewater tank at 150% of potable, commissary agreement, and an annual MFF permit.
Both paths converge on identical NSF/ANSI 61 requirements for water-contact equipment. The MFF guide is the more prescriptive of the two for water tanks specifically (§IV.H), so its provisions are cited below as the design-side controlling reference. Components and documentation that satisfy MFF §IV.H also satisfy CalCode for stationary equipment.
The relevant provisions for this system are:
| Citation | Requirement | Implication for this build |
|---|---|---|
| §III.E.10 | "All equipment shall be listed as certified or classified for sanitation by an ANSI accredited certification program, such as, NSF." | Every wetted component on the skid (tanks, pumps, filters, valves, fittings, tubing, UV chamber, instrumentation in product water) must carry NSF or other ANSI-accredited certification (NSF, ITS/ETL, UL EPH, CSA). Documentation must be available at plan check. |
| §IV.C | Equipment and plumbing must carry ANSI-accredited sanitation certification. "In the absence of applicable ANSI sanitation certification, the equipment design, construction and installation is subject to approval by this Department." | Provides an explicit plan-check approval path for components without formal certification (e.g. converted Sanke kegs for T-101 / T-102) — material declaration and design submittal are accepted in lieu of vendor-supplied certification. |
| §IV.H.1 | "Water tanks and plumbing shall be constructed of food grade material as approved by an ANSI accredited testing organization for drinking water." | T-101 and T-102 must use NSF/ANSI 61-listed material (or equivalent). NSF/ANSI 51 alone (food equipment surfaces, the typical default certification on stainless beer kegs) does not satisfy this — vendor confirmation of NSF 61 material compliance is required, OR plan-check approval per §IV.C must be obtained before installation. |
| §IV.H.2 | "Interiors shall be smooth and free of recesses and crevices and capable of draining completely." | Drives the electropolished interior preference and the dished/sloped bottom requirement on both T-101 and T-102. Tank outlet must be at the lowest point of the vessel. |
| §IV.H.3 | "Tanks must be adequately vented for flow. Water tank vents shall terminate in a downward direction and are to be covered with 16 mesh per square inch screen or equivalent..." | Both tank vents (T-101 and T-102) must use downward-facing sanitary vent caps with screened or filtered openings. |
All vendor documentation supporting these requirements (NSF certifications, material declarations, vessel approvals) shall be assembled into the plan-check submittal package alongside this specification.