Grundfos DME Pumps
Spare Parts for DME Range Pumps
Product Summary
Genuine and compatible spare parts for the Grundfos DME digital diaphragm dosing pump, the high-capacity speed-controlled pump used across Australia for bulk chlorination, coagulant, caustic and acid dosing in water and wastewater treatment and industry. Both DME sizes share the same build (large dosing head, diaphragm, suction and discharge valves, vent valve and leak detector), so tick what you need and we’ll match the exact kit to your nameplate (e.g. DME 375-10 AR-PV/V/G).
Spare Parts List
✓ Tick the parts you need. Grundfos DME kits are matched to the dosing head material and pump size, so your nameplate model is all we need to get them right. Not sure which items? Add a photo of the nameplate and we’ll work out the kit for you.
| Select | Wear / Service Item | Function & when to replace |
|---|---|---|
| Common Service Kits | ||
| Spare Parts Kit | The standard service kit: suction and discharge valves with the diaphragm, matched to your head material, gasket and valve ball codes (e.g. PP/E/G, PV/V/G, SS/V/SS). Fit it at the service interval or whenever output drops off. | |
| Diaphragm Kit | Replacement diaphragm for the DME 375 or 940. Replace after a diaphragm leak alarm or at the service interval. | |
| Valve Kit | Complete suction and discharge valves with balls, seats and O-rings, matched to your material codes. The usual fix for lost prime, back-flow or inaccurate dosing. | |
| Complete Dosing Head | Fully assembled dosing head for your size and materials. The quickest fix for a cracked, chemically attacked or heavily scaled head. | |
| Vent Valve & Valve Balls | Vent valve for priming and degassing, and replacement valve balls (glass or stainless steel) where only the balls are worn. | |
| Other Core Parts | ||
| Diaphragm Leak Detector | The leak detection sensor fitted behind the diaphragm. Replace if it gives false alarms or after chemical has reached it. | |
| Injection Unit | Injection unit at the dosing point, sized for DME flows. Replace if scaled, blocked or leaking. | |
| Suction Lance / Foot Valve | Suction lance or foot valve with low-level and empty-tank sensing to suit the DME level inputs. | |
| Pressure Relief / Loading Valve | Pressure relief valve to protect the pump and discharge line, or a pressure loading valve to hold a steady counter pressure. | |
| Pulsation Damper | Smooths the discharge flow and reduces pressure peaks at DME flow rates, especially on long discharge lines. | |
| Signal & Power Cables | Level input, pulse/0–20 mA, relay output, external stop and mains cables with the correct M12 plugs for the DME. | |
| Complete Replacement Pump | When a repair doesn’t stack up, we quote a like-for-like DME from the model on your nameplate. | |
How we confirm the exact part: DME kits depend on pump size, dosing head material, gasket and valve ball. Your nameplate carries all of it in the type key (e.g. DME 375-10 AR-PV/V/G: PV = PVDF head, V = FKM gaskets, G = glass balls; PP = polypropylene, SS = stainless steel, E = EPDM). Tick the items above and add a nameplate photo, and we’ll confirm the correct part and price for your exact pump.
Models
Spare parts are available for both DME sizes in the current Grundfos Australia range. The first number on your nameplate (e.g. DME 375-10) is the maximum flow in l/h; the second is the maximum pressure in bar.
Models & Key Specifications
| Model | Max flow (l/h) | Max pressure (bar) | Dosing head (AU range) | Valve balls |
|---|---|---|---|---|
| DME 375-10 | 375 | 10 | PP, PVDF or stainless steel | Glass (SS on stainless head) |
| DME 940-4 | 940 | 4 | PP or PVDF | Glass |
Control variant AR (front or side panel): manual, pulse, 0/4–20 mA, batch and timer modes with digital stop, NO/NC relay outputs, pre-empty and empty level inputs, diaphragm leak detector. 800:1 turndown, G2 chemical connections, 240 W motor in IP65 enclosure. Gaskets EPDM or FKM to suit the chemical.
Troubleshooting
Pump runs but does not dose
Likely cause: air in the dosing head, a dry or blocked foot valve, worn or dirty suction/discharge valves, or a blocked injection unit. Action: open the deaeration valve and prime the pump; clean the foot valve strainer; check the injection unit for scale or crystallised chemical; if output does not return, fit the valve kit.
Air lock or gassing (sodium hypochlorite, peroxide)
Likely cause: outgassing chemical collecting in the dosing head, often worse with long or warm suction lines. Action: keep the suction line short and flooded where possible, and use the vent valve with a return line to the tank to clear gas.
Diaphragm leak alarm or chemical at the drain hole
Likely cause: a ruptured or fatigued diaphragm. Action: isolate the pump, flush the dosing head and replace the diaphragm, or fit the full spare parts kit. Do not keep running: chemical can reach the drive behind the diaphragm.
Pump alarms or stalls on high pressure
Likely cause: a closed or blocked discharge line, a seized injection unit, or a system pressure above the pump rating. Action: check discharge valves are open, clean or replace the injection unit, and confirm the counter pressure suits the model (10 bar on the DME 375-10, 4 bar on the DME 940-4). Fit a pressure relief valve if one is missing.
Dosing rate inaccurate or drifting
Likely cause: worn valve balls and seats, too little pressure difference across the head (a pressure loading valve may be needed), siphoning, or a calibration that no longer matches site conditions. Action: fit the valve kit, check the pressure differential and recalibrate the pump.
Leaking at the dosing head or connections
Likely cause: loose dosing head screws, perished O-rings, or connection nuts and inlays damaged by over-tightening. Action: fit the spare parts kit (valves, diaphragm and O-rings), torque the head screws evenly and replace damaged connection parts.
Display dark, no power or motor fault alarm
Likely cause: supply fault, a damaged mains or signal cable, or a fault in the drive or electronics. Action: check the supply and cables; note any alarm shown on the display. A drive or electronics fault usually means a replacement drive or pump, so send us the nameplate model and alarm details.
Request for Quotation
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Not sure which parts? Just send a photo of the nameplate or part below.