Dosing-pump service — replacement head identification
A replacement-head enquiry begins with the installed pump’s identity. Record its full type and execution codes, then establish whether the order covers a head body, an assembled liquid end or only the diaphragm and valve service parts.
Replacement liquid-end heads and associated service parts for diaphragm chemical dosing pumps. This guide addresses identification, kit contents and checks after replacement; general head-material selection, degassing performance and suction/discharge sizing are covered by the Dosing pump head guide. Complete pumps, drive assemblies and packaged dosing skids remain separate equipment.
Use the pump’s execution code before comparing head dimensions
ProMinent lists its beta/ X service kits by pump type and material identity code. Its Sigma/ 2 catalogue also distinguishes diaphragm sizes and executions, including an earlier diaphragm execution. Obtain the manufacturer’s applicable replacement reference from the complete installed-pump identification. [1][2]
Supply the nameplate, serial or production details, the existing head identification and photographs of the suction, discharge and vent connections. Include any earlier service record showing a change of head or diaphragm execution.
Confirm diaphragm attachment, head-to-drive interface, screw arrangement and connection fittings against the approved replacement drawing. Diaphragm diameter and stroke data can help identify an assembly, but matching those dimensions alone does not establish interchangeability.
Reconfirm the present chemical, concentration and temperature if the duty has changed since installation. Ask for the material code of the complete wetted combination, including the diaphragm face, head body, valves and seals.
02
Read the parts list behind the words “head” and “service kit”
Grundfos lists separate DDA-C service references for diaphragm, valves and complete head. [3]
Catalogue example
Difference that affects the replacement order
ProMinent beta/ X
The listed spare set contains the dosing diaphragm, complete suction and pressure valves and a connection set. The stainless-steel version instead supplies valve seats, seals and balls without the complete valves. [1]
ProMinent Sigma/ 2
The PVT and SST kit lists differ: the PVT list includes valve assemblies and an elastomer sealing set, while the SST list specifies its own ball, seat-disc and composite-seal items. Check the actual material execution’s list. [2]
Grundfos SMART Digital S DDA-C
On DDA-C, the dosing diaphragm, safety diaphragm, flange, head, valves and fasteners are distinct parts. Check the ordered reference’s contents. [3]
Request an itemised quotation with part numbers, quantities and the components to be retained. Ask explicitly about connection adapters, head screws, sealing parts and any pressure-sensor connection fitted to the existing head.
03
Close the service job with the model’s reassembly and verification record
After DDA-C diaphragm leakage, Grundfos requires power isolation and prevention of unintended starting. Service personnel must check for liquid entering the housing; that condition requires the manual’s repair action before return to use. [3]
That model’s reassembly procedure covers drainage, seal seating, valve direction, cross-tightening and follow-up fastener checks. It requires deaeration and sensor calibration when a new head with pressure sensor is fitted. Obtain the actual pump’s procedure and settings. [3]
Agree how the serviced pump’s delivered quantity and repeatability will be checked at the operating duty. Record the liquid, suction/discharge conditions and controller settings with that test, and assess external leakage separately from the dosing result.
Retain the fitted head and service-part references, service date, required follow-up and any calibration record with the pump’s maintenance file. State the replacement assembly’s mass and any handling or access requirements before arranging the work.
This procurement and handover record accompanies the manufacturer’s service instructions. It supplies no universal tightening torque, allowable leakage rate or dosing-repeatability guarantee.
04
Replacement-head enquiry record
Paste it into your enquiry below or into an email to a maker, then replace every bracket.
Installed pump: [manufacturer, full type/execution, serial and production details]
Existing head: [part reference, material code, identification photos and previous modifications]
Required supply: [bare body, complete liquid end, diaphragm/valve kit or individual parts]
Duty confirmation: [chemical, concentration, temperature, flow and suction/discharge conditions]
Fit and contents: [diaphragm attachment, fasteners, adapters, valves, seals and sensor connection]
Service provision: [applicable manual, responsible personnel and condition after any leakage]
Completion record: [model-specific reassembly/follow-up, calibration and dosing/leakage checks]
Delivery: [itemised references, assembly mass and installation access]
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Compiled and source-reviewed by the CNFX editorial team.
Each manufacturer above links to the page on that company's own website where the product is listed, with the date we checked it. How we source and review
· Page last updated 23 October 2026
Buyer questions
Does a spare-parts kit include a new head body and complete valves?
Check its itemised contents. ProMinent’s beta/ X catalogue changes the valve content for the stainless-steel execution, and Grundfos lists a complete dosing head separately from diaphragm and valve service references. [1][3]
What extra check follows replacement of a DDA-C head with a pressure sensor?
The DDA-C manual calls for sensor calibration when fitting a new head with pressure sensor. Keep the calibration result with the service record. [3]
Sources and evidence scope
Sources checked 2026-10-23T10:13:05+08:00. ProMinent’s catalogues define model- and material-specific spare sets. Grundfos describes the SMART Digital S DDA-C head and service requirements; those instructions retain that model scope.
