Metering Pumps

Reference: RO-SPEC-001 §3.8, §5.5 — Water System Spec (Two-Tank Architecture)

Overview

Three identical diaphragm metering pumps inject mineral concentrates into the water stream between solenoid valve SV-TREAT and Tank 2 (T-102). They operate only when SV-TREAT is open (T-102 calling for fill). Dosing rates are set by the active HMI recipe preset and are ratio-based relative to the transfer flow measured at FT-103.

Pump Tag	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

Conductivity sensor CT-103 (located at T-102 inlet, after the injection point) provides closed-loop TDS verification against the active recipe target.

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1. Core Performance & Compliance

• Quantity: 3 pumps (identical hardware; interchangeable spares)

• Certification (design intent vs. procured units)

  • Design intent: NSF/ANSI 61 (drinking water system components).
  • Procured (Rev H): Three Grundfos DDC 6-10 AR-PVC/V/C-F-31I001FG units (Grundfos Product No 98586903, EAN 5711497701275). The official Grundfos catalog lists the 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' nameplates (Made in France, EU production run) carry CE, CSA-US, EAC, and RCM (registration N20693), but do not stamp the NSF 61 mark. This is consistent with regional marking practice: the global model is NSF 61–approved per the catalog, but EU-built units don't redundantly carry the North American sanitation mark on the plate. Plan-check submittal therefore combines the catalog page (model-level NSF 61 evidence) with nameplate photos (regional marks) plus the materials declaration; the San Diego DEH MFF §IV.C path is invoked as the formal regulatory mechanism. See §8 Plan-check submittal package.

• Flow Rate Range

  • 0.1–100 mL/min adjustable (per water-system-spec §3.8)
  • Practical duty range during normal recipes: 1–15 mL/min (see §6 Dosing Duty Point Analysis)
  • Note: Many pumps are rated in GPH on the nameplate. 1 GPH ≈ 63 mL/min. Convert before comparing.

• Turndown Ratio

  • Must support stable, precise dosing below 5 mL/min
  • Preferred: ≥ 1000:1 turndown — DDC achieves 1000:1, DDA achieves 3000:1. Either is a large margin over the application's actual ~10:1 dynamic range (1.5–14.4 mL/min, see §6).

• Pressure Rating

  • Minimum 50 PSI (3.4 bar)
  • Must overcome back-pressure in the line between SV-TREAT and T-102

• Accuracy / Repeatability

  • ≤ ±2 % of setpoint (preferred ±1 %)

• Adjustment Type

  • Digital stepper-motor drive (preferred) or digitally-controlled solenoid drive with equivalent precision
  • Onboard digital display showing dosing rate
  • Resolution: 0.1 % increments OR 0.1 L/h increments

2. Wetted Materials (Sanitary Grade)

Procured path (DDC 6-10): PVC dosing head, PTFE diaphragm, ceramic valve balls, FKM gaskets — the textbook diaphragm-pump wetted-parts combination for chloride / sulfate / bicarbonate dosing. NSF/ANSI 61 is included in Grundfos's catalog approval set for this exact product number (98586903) at the model level. The procured EU-build units' nameplates show CE / CSA-US / EAC / RCM but not the NSF 61 mark — see §5 Tier 0 for the full approval listing and §8 for the plan-check submittal mechanics (catalog page + nameplate photos + §IV.C citation).

General guidance (any substitute pump): Materials in the liquid path should be acceptable for potable or food-contact service per manufacturer documentation; NSF/ANSI 61 on the model and on the nameplate is the gold standard.

• Dosing Head / Body

  • Acceptable: PVC, Polypropylene (PP), PVDF, or 316SS
  • PVDF or 316SS preferred for long-term chemical compatibility

• Gaskets / O-Rings / Valve Seats

  • FKM (Viton) OR EPDM
  • PTFE gaskets acceptable

• Valve Balls

  • Ceramic (preferred) or 316SS

• Diaphragm

  • PTFE (Teflon) faced — mandatory for chemical resistance

• Chemical Compatibility

  • Must support continuous dosing of the following at concentrate strength:
    • Magnesium Sulfate (MgSO₄) — mildly corrosive in solution
    • Calcium Chloride (CaCl₂) — corrosive to metals; avoid brass/copper
    • Sodium Bicarbonate (NaHCO₃) — mildly alkaline
  • Concentrate preparation follows the "A Waste of Coffee" method (see §6): ~35–75 g dry mineral per 800 mL distilled water. These are dilute solutions; material compatibility is not demanding.

3. Electrical & Control Interface

• Power

  • 100–240 VAC, 50–60 Hz (universal input)
  • Standard US 3-prong plug (NEMA 5-15P) or hardwired to panel
  • Typical power draw: 20–30 W per pump

• Control Interface

  • "AR" variant (Analog + Relay) or equivalent
  • Must support: external stop via dry-contact relay (PLC-controlled)
  • 4–20 mA analog input for proportional dosing rate control (optional but preferred for future closed-loop TDS trim)

• PLC Integration

  • Relay module: AutomationDirect P2-08TRS (Form-C relay output)
  • PLC enables/disables each pump independently via relay dry contact
  • Pump runs at its onboard setpoint when relay is closed; stops when open
  • Dosing rate is set manually on the pump's own display per the active HMI recipe; future upgrade path is 4–20 mA proportional control from PLC

• Fittings

  • 1/4″ OD tubing, standard compression fittings (suction and discharge)
  • 316SS or PVDF injection quill at the discharge point

• Enclosure Rating

  • IP65 / NEMA 4X minimum (wet environment near tanks)

4. Constraints & Preferences

• Pump Type [CRITICAL]

  • Diaphragm metering pump required
  • No peristaltic pumps (tube wear and inconsistent dosing at low rates)

• Drive Type

  • Stepper-motor drive (e.g., Grundfos DDA) preferred for precision at low flow rates and long diaphragm life
  • Controlled solenoid drive (e.g., ProMinent gamma/X, Walchem EWN) is acceptable if turndown and precision meet §1 requirements

• Price Range

  • $300–$1,200 per pump (new)
  • Used / surplus / open-box units acceptable if NSF-61 certification can be verified on the data plate and wetted parts are in serviceable condition

• Preferred Manufacturers

  • Grundfos (DDA series)
  • ProMinent (gamma/X series)
  • Walchem / Iwaki (EWN series)
  • LMI / Milton Roy (PD series)

5. Qualified Models

The following models meet all §1–§4 requirements. Any of these can be used; all three pumps should be the same model for spare-parts commonality.

Tier 0 — Procured (this build)

Grundfos DDC 6-10 AR-PVC/V/C-F-31I001FG

Manufacturer	Grundfos
Range	SMART Digital (Digital Dosing)
Type key	DDC 6-10 AR-PVC/V/C-F-31I001FG
Product No	98586903
EAN	5711497701275
Quantity in this build	3 (identical, fully interchangeable for spares)
Source	Surplus / open-box (per ebay-finder listing 52)

Part of Grundfos's SMART Digital dosing platform — the same control firmware, click-wheel UI, and diagnostic ecosystem as the DDA, with a digitally-controlled solenoid drive in place of the stepper.

Type-code decode

Segment	Meaning
DDC	SMART Digital range — solenoid-driven digital metering pump
6-10	6 L/h max flow @ 10 bar max pressure (Grundfos naming convention: L/h × bar)
AR	Control variant: Analog 4–20 mA input + dry-contact stop Relay
PVC	Dosing head material: PVC (polyvinyl chloride)
/V	Gaskets / O-rings: FKM (Viton)
/C	Valve balls: Ceramic
-F	Standard installation set with 4/6 mm tubing (factory-supplied, 3 m)
-31	Voltage / region code (1 × 100–240 VAC)
I001FG	Grundfos internal order suffix

Manufacturer specifications (Grundfos catalog, Product 98586903)

Parameter	Value	Notes
Drive	Digital solenoid (SMART Digital, variable-speed)	Same control platform as DDA
Max flow	1.585 US GPH	= 6.0 L/h = 100 mL/min
Max flow @ 50 % slow mode	0.79 US GPH	for higher-viscosity fluids
Max flow @ 25 % slow mode	0.40 US GPH	for highest-viscosity fluids
Min flow	6.0 mL/h (0.1 mL/min)
Turn-down ratio	1000:1
Repeatability	±1 %
Stroke resolution	0.1 % continuous	digital stroke control
Max operating pressure	145.04 psi (10 bar)
Max viscosity (100 % mode)	50 mPa·s	water ≈ 1 mPa·s; mineral concentrates ≈ 1.5–2 mPa·s
Max viscosity (50 % slow mode)	1 800 mPa·s
Max viscosity (25 % slow mode)	2 500 mPa·s
Max suction lift, operation	19.7 ft (6.0 m)	self-degassing valve
Max suction lift, priming	6.56 ft (2.0 m)
Liquid temperature range	32–113 °F (0–45 °C)
Ambient temperature range	32–113 °F (0–45 °C)
Max power input (P1)	22 W
Voltage	100–240 VAC universal, 50/60 Hz
Inrush current	25 A @ 230 V for 2 ms	use Type C MCB; stagger PLC enables across pumps
Mains cable (factory)	4.92 ft (1.5 m), EU plug	re-terminate to NEMA 5-15P or hard-wire to panel for US service
Enclosure	IP65 / NEMA Type 4X
Pump inlet / outlet	4 mm ID × 6 mm OD hose (3 m supplied)	metric — see Fittings note below
Net weight	4.41 lb (2.0 kg)	each
Gross (shipping) weight	6.62 lb (3.0 kg)	each
Color	Red (Grundfos signature)

Wetted-parts materials (per Grundfos catalog, type code PVC/V/C)

Component	Material
Dosing head	PVC (polyvinyl chloride)
Diaphragm	PTFE (composite)
Valve balls	Ceramic
Valve gaskets / O-rings	FKM (Viton)
Factory hose	flexible PE/PTFE, 4/6 mm

PVC + PTFE + ceramic + FKM is the textbook wetted-parts combination for diaphragm-pump dosing of dilute chloride, sulfate, and bicarbonate solutions. None of these materials interact problematically with the §6 mineral concentrates at the prescribed dilutions, and all four are recognized food-contact polymers (FDA 21 CFR) when used as the wetted boundary in food-equipment dosing applications.

Approvals — model (catalog) vs. nameplate (procured units)

Source	Approval marks
Grundfos product catalog (Product 98586903)	CE · CSA-US · NSF/ANSI 61 · EAC · RCM
Procured units' nameplate (Made in France, EU production run, inspected)	CE · CSA-US · EAC · RCM (reg N20693) — plus China RoHS and WEEE pictograms; NSF 61 not stamped on plate

NSF/ANSI 61 (Drinking Water System Components — Health Effects) is part of the official Grundfos approval set for this exact product number at the model level — the model is manufacturer-claimed compliant with the standard that San Diego DEH plan-check looks for. The EU-built units do not redundantly stamp the NSF 61 mark on their nameplates (regional marking practice for plates produced in France / for EU primary distribution); the catalog page is the documentary evidence of model-level approval. See §8 for the plan-check submittal mechanics.

Control interface (AR variant)

Capability	Detail
Front panel	Click-wheel UI + digital display (same UI family as DDA — common operator training)
Analog input	0/4–20 mA (proportional dosing-rate control)
External stop input	Dry contact (PLC-driven via AutomationDirect P2-08TRS relay)
Output relays	2 (alarm / status — wire back to PLC discrete inputs for fault telemetry)
Pulse control input	Yes (future option: pace dosing to FT-103 flow pulses)
Level control input	Yes (future option: low-concentrate alarm from level switch in concentrate jug)

Fittings note

The factory installation set is metric (4 mm ID × 6 mm OD hose), while the §3 / §5 system spec specifies 1/4″ OD compression fittings at the injection quill. The two are close (6 mm = 0.236″, 1/4″ = 0.250″) but not interchangeable — convert at the discharge with a Parker / Swagelok metric-to-imperial adapter, or replace the inlet/outlet fittings on the pump head with 1/4″ compression equivalents during install. Document the chosen approach in the as-built and on the BOM erratum.

Why the DDC is the right pump for this build

This duty point is small. The DDC is genuinely overspec'd for it — across every dimension that matters:

Requirement (this build)	DDC 6-10 capability	Margin
Dosing dynamic range: ~10:1 (1.5 → 14.4 mL/min, §6)	1000:1 turndown	100×
Discharge pressure: ≤ 50 psi (3.4 bar) between SV-TREAT and T-102	145 psi (10 bar)	~3×
Precision needed (with CT-103 closed-loop on T-102 inlet): ±5 % is acceptable	±1 % repeatability, 0.1 % stroke resolution	5×
Liquid viscosity (water-thin mineral solutions) ≈ 1.5 mPa·s	50 mPa·s in 100 % mode	~33×
Wetted-material compatibility for dilute MgSO₄ / CaCl₂ / NaHCO₃	PVC + PTFE + FKM + ceramic balls	textbook match for chloride / sulfate / bicarbonate dosing
Potable-water certification	NSF/ANSI 61 in Grundfos catalog approval set	meets §1 design intent
Voltage / control flexibility	Universal 100–240 VAC; AR variant has 4–20 mA and dry-contact stop	meets every interface in §3
Wash-down / installation environment	IP65 / NEMA 4X	matches every other panel-mounted device on the skid

The two textbook reasons to prefer a stepper-driven DDA over a solenoid-driven DDC are (a) ultra-low pulsation for inline blending in a continuously-flowing pipe, and (b) higher turndown for very wide recipe ranges. Neither matters here:

• Pulsation is mixed out before it can affect a poured cup by the Koflo 105955Q34R static mixer on the post-injection line and by T-102's tank volume, which buffers the dose into ~150 L of treated water before any of it leaves the skid.
• Turndown isn't the binding constraint — even the strictest recipe (Rao/Perger NaHCO₃ at 1 GPM = 1.5 mL/min) sits comfortably above the DDC's minimum stable output of 0.1 mL/min.

In industrial use the DDC line is routinely deployed dosing chlorine, soda ash, and coagulant into municipal water mains and beverage process lines. Three of them metering coffee mineral concentrates into a 4 GPM recirculating skid is — to be candid — luxury overkill. That is exactly the safety factor wanted on a system that has to run reliably in a food-truck environment, and exactly the kind of margin a plan checker likes to see in the submittal.

The DDA remains the precision champion (see Tier 1) for an apples-to-apples comparison, but for this build the DDC is the right pump — not a compromise.

Tier 1 — Best Match (stepper motor, highest precision)

Grundfos DDA 7.5-16 AR (preferred)

Parameter	Value
Type key (PVDF/PTFE)	DDA 7.5-16 AR-PV/T/C-F-31U2U2FG
Type key (316SS/PTFE)	DDA 7.5-16 AR-SS/T/SS-F-31VVBG
Max flow	7.5 L/h (125 mL/min) @ 16 bar (232 psi)
Turndown	3000:1
Drive	Variable-speed stepper motor
Accuracy	±1 %
Diaphragm	PTFE
Power	24 W, 100–240 VAC, 50/60 Hz
Enclosure	IP65 / NEMA 4X
Certifications	NSF/ANSI 61, CSA-US, CE
Control	AR = Analog (4–20 mA) + Relay (dry contact stop)
Approx. price (new)	$800–$1,200

Notes: The DDA's stepper-motor drive gives it the highest turndown (3000:1) and the smoothest pulsation profile of any pump on this list — it is the precision champion if a new-purchase budget and lead time allow. For this build the procured DDC (Tier 0) covers the §6 duty envelope with comfortable margin and shares the same SMART Digital control platform, so the DDA was moved from "preferred" to "premium alternative" rather than being discarded. Available with Grundfos 2-week quick-ship through authorized distributors if a future build wants the upgrade.

Tier 2 — Strong Alternatives (solenoid drive, good precision)

ProMinent gamma/X GMXa 1604 (PP or PVDF head)

Parameter	Value
Max flow	3.6 L/h (60 mL/min) @ 232 psi
Stroke volume	0.30 mL/stroke × up to 200 strokes/min
Drive	Controlled solenoid
Stroke adjustment	Electronic, 0–100 % continuous
Diaphragm	PTFE-faced (vPTFE option available)
Certifications	NSF/ANSI 61 approved liquid ends
Approx. price (new)	$500–$900

Notes: The gamma/X has predictive intelligence (sensor-free pressure measurement, fault detection). Widely deployed in municipal water treatment; commonly found on surplus markets. The GMXa 1009 variant (9 L/h, 145 psi) is also acceptable if 1604 is unavailable.

Walchem EWN-B11 or EWN-B16 (PVC head, PTFE/EPDM diaphragm)

Parameter	Value
Max flow (B11)	0.6 GPH (38 mL/min) @ 150 psi
Max flow (B16)	1.0 GPH (63 mL/min) @ 105 psi
Drive	Solenoid, up to 360 SPM
Control	R variant = manual + analog; Y variant = full-featured
Diaphragm	PTFE + EPDM (dry end)
Certifications	NSF/ANSI 61, WQA, UL, CSA
Approx. price (new)	$300–$600

Notes: Good budget option. High stroke rate (360 SPM) provides fine resolution. Available with PVC, PVDF, or 316SS heads. The EWN-Y controller adds flow measurement capability when paired with the EFS sensor.

LMI / Milton Roy PD Series (PD7xx)

Parameter	Value
Max flow	Varies by liquid end code; up to ~3 GPH (190 mL/min)
Turndown	200:1
Accuracy	±3 %
Drive	Solenoid
Diaphragm	Liquifram™ (PTFE)
Certifications	NSF/ANSI 61
Power	110–240 V, 50–60 Hz
Enclosure	IP65 / NEMA 4X
Approx. price (new)	$300–$700

Notes: Widely available and economical. The ±3 % accuracy is adequate for this application because CT-103 provides closed-loop TDS verification. Less precise than Grundfos DDA but significantly cheaper. Common on surplus markets due to large installed base in municipal water treatment.

6. Dosing Duty Point Analysis

This section calculates the actual metering pump duty range for the system's operating conditions, to help evaluate whether a given pump model is suitable.

Transfer Flow Rate

When SV-TREAT opens, P-102 directs flow from T-101 through the UV unit and into the mineral injection manifold en route to T-102. The transfer flow rate depends on P-102's VFD speed setting during fill mode.

Scenario	Transfer Flow	Notes
P-102 at full speed	~4 GPM	SV-RECIRC closes, full flow to SV-TREAT
P-102 at reduced speed	~2 GPM	PLC may throttle during T-102 fill
Minimum practical	~1 GPM	Conservative low-end for duty calc

Recipe Dosing Rates (from water-system-spec §5.5)

Preset	Min. A (MgSO₄)	Min. B (CaCl₂)	Min. C (NaHCO₃)	Target TDS
SCA Gold Cup	2.4 mL/gal	3.1 mL/gal	1.8 mL/gal	~120 ppm
Light Roast	3.6 mL/gal	1.5 mL/gal	2.0 mL/gal	~100 ppm
Medium Roast	2.0 mL/gal	2.5 mL/gal	2.2 mL/gal	~130 ppm
Rao/Perger	3.0 mL/gal	0.0 mL/gal	1.5 mL/gal	~85 ppm

Calculated Pump Output Range

Pump output (mL/min) = Recipe rate (mL/gal) × Transfer flow (GPM)

Condition	Dosing Rate	Pump Output
Maximum: Light Roast MgSO₄ @ 4 GPM	3.6 mL/gal × 4	14.4 mL/min
Typical: SCA Gold Cup CaCl₂ @ 2 GPM	3.1 mL/gal × 2	6.2 mL/min
Minimum: Rao/Perger NaHCO₃ @ 1 GPM	1.5 mL/gal × 1	1.5 mL/min
Zero: Rao/Perger CaCl₂ (any flow)	0.0 mL/gal	0 (pump off)

Practical duty envelope: 1.5–15 mL/min

All qualified models in §5 cover this range with margin. The procured Grundfos DDC 6-10 (0.1–100 mL/min, 1000:1 turndown) brackets this envelope with roughly an order of magnitude of headroom on both ends — operation sits in the middle of the pump's curve, not near either limit. The DDA (minimum output ~0.04 mL/min, 3000:1 turndown) provides even more range for experimentation with extreme recipes.

Concentrate Preparation Reference

Dosing rates above assume concentrates prepared per the "A Waste of Coffee" method (Alex Levitt), where 1 mL of concentrate added to 1 gallon of RO permeate raises TDS by 10 ppm (expressed as CaCO₃):

Concentrate	Dry Mineral	Dissolve In
Magnesium sulfate (MgSO₄·7H₂O)	74.6 g	800 mL distilled water
Calcium chloride (CaCl₂, anhydrous)	33.6 g	800 mL distilled water
Sodium bicarbonate (NaHCO₃)	50.9 g	800 mL distilled water

These are the gallon-scale concentrates. The recipe mL/gal rates in the HMI presets are calibrated to these concentrate strengths. If different concentrate strengths are used, the HMI recipe rates must be recalibrated during commissioning.

7. Sourcing Strategy & Search Keywords

New Purchase (authorized distributors)

• Grundfos DDA: burtprocess.com, grundfos.com product selector, local Grundfos distributor — 2-week quick-ship available
• ProMinent gamma/X: prominent.us, pulseinstruments.net — contact local rep for pricing
• Walchem EWN: walchem.com, instrumart.com, cannonwater.com
• LMI PD: procompumps.com, lmipumpcatalog.com

Used / Surplus (eBay, surplus dealers)

Search combinations of:

• "NSF 61" metering pump diaphragm
• Grundfos DDA 7.5-16
• Grundfos DDA dosing pump
• ProMinent gamma X or ProMinent GMXa
• Walchem EWN metering pump
• LMI PD series pump or LMI PD7
• "digital dosing pump" NSF diaphragm

Filter for:

• Used / refurbished / open-box / industrial surplus
• Listings with data plate photos (verify NSF-61 mark)
• Listings with spec sheets
• Confirm 100–240 VAC universal voltage (avoid 24 VDC-only variants)
• Confirm tubing size (1/4″ OD standard)

What to Verify on Any Used Pump

1. Certification strategy: Prefer NSF/ANSI 61 on the data plate if the jurisdiction requires it; otherwise document CE/cULus + materials for a §IV.C submittal (same as procured DDC path).
2. Voltage: 100–240 VAC, 50/60 Hz
3. Diaphragm condition (replace if unknown history — kits are ~$50–$100)
4. Check valve ball and seat condition
5. Confirm correct liquid end material (avoid brass or exotic alloys)
6. Confirm control interface supports dry-contact relay stop

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8. Procured units (Rev H) — Plan-check submittal package

8.1 Procurement summary

What was bought: three Grundfos DDC 6-10 AR-PVC/V/C-F-31I001FG pumps (Grundfos Product No 98586903, EAN 5711497701275), matching RO-SPEC-001 §3.8 and the BOM Rev G line item. Sourced via surplus / open-box channel (see ebay-finder project, listing 52). Spec capture and per-unit photos in the ebay-finder record; specs cross-reference exactly to the Grundfos product catalog page for 98586903.

8.2 NSF/ANSI 61 status

Manufacturer-claimed (catalog-level): Per the official Grundfos product catalog page for Product No 98586903, this exact model is listed with the following approvals:

CE · CSA-US · NSF/ANSI 61 · EAC · RCM

NSF/ANSI 61 — Drinking Water System Components — Health Effects — is therefore a manufacturer-claimed approval at the model level. This is the standard San Diego DEH plan-check looks for on potable-water-touching components.

Procured units' nameplate (inspected): All three procured pumps are Made in France (EU production run). Their nameplates carry:

CE · CSA-US · EAC · RCM (registration N20693) — plus China RoHS (10-yr Environmentally Friendly Use Period) and WEEE disposal pictograms.

The NSF 61 mark is not stamped on these specific nameplates. This is consistent with regional marking practice — Grundfos typically does not stamp the NSF 61 mark on plates intended for EU primary distribution, even when the global model carries the NSF 61 catalog approval. (Pumps from US / North American production runs of the same Product No 98586903 typically do carry the NSF 61 mark on the plate.)

Submittal strategy: Combine the catalog page (model-level NSF 61 evidence) with the nameplate photos (regional marks) plus the materials declaration. Cite San Diego DEH MFF §IV.C as the formal regulatory mechanism — "In the absence of applicable ANSI sanitation certification, the equipment design, construction and installation is subject to approval by this Department." — with the catalog approval and materials documentation establishing technical equivalence.

8.3 DEH submittal package — checklist

Bundle the following into a single PDF (or folder) per pump tag in the plan-check submittal:

#	Document	Where to get it
1	Nameplate photo of each of the three pumps — clear, in-focus, all approval marks legible	Take on bench before installation
2	Grundfos catalog page, Product No 98586903 — the official approval listing (CE / CSA-US / NSF 61 / EAC / RCM)	Save as PDF from https://product-selection.grundfos.com/products/service-special/dosing-service-special/ddc-6-10-ar-pvcvc-f-31i001fg-98586903
3	Grundfos DDC range datasheet / installation guide	Grundfos product literature (download from product page)
4	Wetted-parts materials declaration — type-code decode + material table	Use §5 Tier 0 of this document (export PDF)
5	Materials suitability statement — PVC head / PTFE diaphragm / ceramic balls / FKM gaskets vs. dilute MgSO₄ / CaCl₂ / NaHCO₃ at §6 dilutions	Use §2 of this document + §6 concentrate table
6	§IV.C reference page (San Diego DEH MFF guide) — back-stop only, in case the catalog approval listing isn't accepted as sufficient on its own	Local copy in the regulatory folder of this site
7	Per-unit serial / source record — proof of provenance for the three units	Export from ebay-finder listing 52 (PDF or screenshots)

8.4 Internal traceability

Per-unit inspection notes, photos, and procurement source data live in the ebay-finder project (local LAN viewer at http://192.168.10.100:8001/listing/52?spec_id=1 — not part of the public docs site). Export each unit's record as PDF or screenshots into the DEH submittal folder so the plan checker has a complete chain of custody without needing access to the local network.