central heating pump Help and information on all topics relating to your central heating, air conditioning and ventilation issues.

[Zing]

I have moved into a new house which has a Direct Feed System(unvented)In the 20 months i have lived there,the pump on the system has broken 5 times.I rang the pump manufacturers(Grunfus)and the only explanation they could give me was a dirty system.This time the plumber is adding a cleanser,flushing the system and adding an inhibitor but i am still not convinced this will stop the pump from breaking and there is a more serious problem.After speaking to numerous plumbers with a few mentioning a dirty system,one fella asked me how far away the bypass valve was from the pump and recommended it should be approximately 6 metres.Is this true because mine is practically next to the pump?And if its because of a dirty system,how come with it being a new house?

[stoneyboy]

Zing,
Presumably a new pump is being fitted every time and the old one being replaced under guarantee? What do Grundfos say about the failed pumps?
When you refer to the pump as being broken do you know what has actually happened? Has the pump just stopped working, was there still power to the pump.
If dirt in the system is a problem you can undo the screw on the end of the pump and try freeing it using a screwdriver. If the pump shaft spins freely it is unlikely to be dirt causing the problem.
end

[Zing]

Thanks fo the reply.There is power going to the pump,it still seems to work but the pump starts to scream.Even when you change the flow settings it still screams on all three of them.Grunfus dont seem that bothered to be honest but the plumber has given me a water sample from the system before installing the new pump.He says that the system may have been contaminated from the start and if the pump goes again,to phone Grunfus and ask for somebody to call to the house and investigate.He says they would test the sample themselves

[Perry525]

Does the pipework require a horizontal or vertical circulator?
All pumps work best in vertical pipework, this ensures they do not trap air.

[Zing]

Thanks for the reply.Im not sure and will have to ask the plumber when he comes back because 4 hours after the new pump was fitted,it started screaming again.I phoned Grunfus again and they recommend flushing all the pipework and the radiators thouroughly,putting cleanser in the system again for 2 weeks and then flushing it all again after that.They think there must still have been some dirt somewhere in the system and the pump will pick it up straight away when restarted because i think he said they were magnetised?I seem to be going round in circles!I mean this is my sixth pump in 20 months,five in 12 months.Its surely got to be more than a little bit of dirt hasnt it?