Grundfos DDC Pumps
Spare Parts for DDC Range Pumps
Product Summary
Genuine and compatible spare parts for the Grundfos SMART Digital DDC stepper-driven diaphragm dosing pump, used across Australia for chlorination, pH correction and chemical dosing in water treatment, pools, irrigation and small industrial plants. Both DDC sizes share the SMART Digital S dosing head build (diaphragm, suction and discharge valves, deaeration valve), so tick what you need and we’ll match the exact kit to your nameplate (e.g. DDC 6-10 AR-PVC/V/C-F-31U2U2IG).
Spare Parts List
✓ Tick the parts you need. Grundfos SMART Digital 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, diaphragm and O-rings, matched to your head material, gasket and valve ball codes. Fit it at the routine service interval or whenever output drops off. | |
| Diaphragm Kit | Replacement diaphragm for your pump (44 mm on the DDC 6-10, 50 mm on the DDC 15-4). Replace if chemical shows at the drain hole or at the service interval. | |
| Valve Kit | Complete suction and discharge valves with balls, seats and seals, standard or spring-loaded. The usual fix for lost prime, back-flow or inaccurate dosing. | |
| Complete Dosing Head | Fully assembled dosing head with valves, diaphragm and deaeration valve. The quickest fix for a cracked, chemically attacked or heavily scaled head. | |
| Deaeration Valve | Manual deaeration (vent) valve for priming and releasing gas from the head. Replace if it weeps or will not seal. | |
| Other Core Parts | ||
| Injection Unit | Spring-loaded injection unit at the dosing point, keeping chemical from back-flowing. Replace if scaled, blocked or leaking. | |
| Foot Valve | Foot valve with strainer for the end of the suction line, available with low-level and empty-tank sensing to suit the DDC level inputs. | |
| Suction / Discharge Tubing | Suction, discharge and deaeration tubing sized to your connections (4/6, 6/9, 6/12 or 9/12 mm). | |
| Pressure Relief / Loading Valve | Pressure relief valve to protect the pump and line, or a pressure loading valve to hold a steady counter pressure and stop siphoning. | |
| Connection Kit / Inlays | Union nuts and hose or pipe inlays for the pump inlet and outlet, matched to your connection code. | |
| Signal & Power Cables | Level input, pulse, relay output and mains cables with the correct plugs for SMART Digital pumps. | |
| Complete Replacement Pump | When a repair doesn’t stack up, we quote a like-for-like SMART Digital DDC from the model on your nameplate. | |
How we confirm the exact part: SMART Digital DDC kits depend on pump size, dosing head material, gasket, valve ball and valve type. Your nameplate carries all of it in the type key (e.g. DDC 6-10 AR-PVC/V/C-F-31U2U2IG: PVC head, V = FKM gaskets, C = ceramic balls, 1 = standard valves). 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 SMART Digital DDC sizes in the current Grundfos Australia range. The first number on your nameplate (e.g. DDC 6-10) 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) | Diaphragm (mm) | Dosing head (AU range) |
|---|---|---|---|---|
| DDC 6-10 | 6 | 10 | 44 | PVC, FKM, ceramic balls |
| DDC 15-4 | 15 | 4 | 50 | PVC, FKM, ceramic balls |
Control variant AR: manual speed control, pulse control in ml/pulse, two output relays, low-level and empty-tank inputs, external stop. 1000:1 turndown, G5/8 connections, liquid −10 to +45 °C, 100–240 V, IP65. Other head materials are made to order.
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 below the tank where possible, use the deaeration valve with a return line to the tank, and fit spring-loaded valves for gassing media.
Chemical at the drain hole (diaphragm leak)
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 stalls or knocks against 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 DDC 6-10, 4 bar on the DDC 15-4). 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
Selected Parts:
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Not sure which parts? Just send a photo of the nameplate or part below.