End-of-Life Information
Grundfos DMH Pumps must be disposed of according to local regulations by using a public or private waste collection service. If this is not possible, contact the nearest Grundfos company or service workshop.
To identify the specific product materials, please check the Type key available in the product nameplate as described in the product´s Installation and operating instructions.

Safety Risk

Safety related to materials used

  • The materials used in DMH pumps do not pose any health risk to the person handling them. Please observe the corresponding indications in the Installation and operating instructions for taking the product out of operation.
  • The pump housing is filled with non-toxic hydraulic oil.

Safety related to handling the product

  • The required safety measures for handling the chemical being dosed with this pump should be taken. The parts in contact with the fluid should be rinsed and cleaned before disposal in an environmentally sound way.
  • The product should be taken out of operation according to the recommendations described in the Installation and operating instructions. The necessary precautions when draining the hydraulic oil from the pump should be followed.
  • Care should be taken when handling the pump due to its weight.


Disassembly of the Product

Depending on the pump model, the materials of the product components are:

  • Stainless Steel of different grades
  • Thermoplastics of different compositions
  • Elastomers of different compositions
  • Composites
  • Aluminium
  • Hydraulic oil
  • Electronic scrap

The pump can be disassembled with standard tools.

DesignationName  MaterialSpecial Disassembly Consideration
1pMotorSiemens asynchronous motorUse a long Allen key to remove the motor retaining screws
2pWorm gearingBrass, steel 
3pEccentricSteelApply a slide hammer to remove the complete gear shaft
4pRecuperating springSteelNot available for models 251, 252 and 257
5pSliding plugSteel 
7pCrank Only model 257
MCombined overpressure and degassing valveAluminium housing, FKM elastomer, steel spring 
EDegassing valve Only models 251, 252, 253
9PDiaphragm protection systemSteel 
QDosing diaphragmPTFE 
2Dosing headPVC or PP or PVDF or SS 1.4571 or Hastelloy® C 
3aSuction valve housingPVC or PP or PVDF or SS 1.4571 or Hastelloy® C 
3bDischarge valve housingPVC or PP or PVDF or SS 1.4571 or Hastelloy® C 
 Valve ball cagePVC or PP or PVDF or SS 1.4571 or Hastelloy® C 
 Valve ballGlass or Ceramic or SS 1.4401 or Hastelloy® C 
 Valve gasketsEPDM or FKM or PTFE 
LStroke-length adjustment knobABS, Steel 
FOil-filling screw with dipstickABS, Steel 
VDosing head deaeration screwPVC or PVDF or SS 1.4571 or Hastelloy® C 
 Pump enclosureAluminium or cast iron 
 AR control unitUpper part of enclosure: PPO blend
Lower part of enclosure: aluminium
Electronic Scrap
Only for pumps with control variant AR
4c DMH251 252
DMH 251, 252
4c DMH 253
DMH 253
4c DMH 254
DMH 254
4c DMH 255
DMH 255
4c DMH 257
DMH 257
4c DMH 280
DMH 280
4c DMH 281
DMH 281
4c DMH 283
DMH 283
4c DMH 286 287
DMH 286 287