pump issues

[CXR100]

went to a house today , was on a solid fuel log burner, with a indirect cylinder , piped from log burner to cylinder in 28mm , but splitting from that in 22mm to do the central heating, you had to turn the room stat on to switch the pump on the central heating on. the customer was complaining that there was a long delay after turning the stat up to 35 to the radiators heating up , regardles of how much fire was going, this is a problem that only started occuring to him, i replaced the pump , thought it was sticking after it made a loud bearing kind noise after i turned the speed down from 3 to 1, noise louder on 1 , loudish on 2 and nothing on 3, but after i replaced it it still makes the same noise, but radiators circulate straight away. also the radiator closest to the pump makes a masive circulating noise when pump on speed 3, any ideas on what it is????? thanks for leading the long post!!!!!! hope it makes sence

 

[diamondgas]

initially sounds like circulation problems CXR100 ... blockage in the heating primaries maybe?

 

[CXR100]

i took some pics of the pipework!!! ill try and upload them tooomorow! all the rads were heating up fine but one making a big circulation noise!

 

[diamondgas]

You could just turn the pump down or fit an automatic bi-pass if excessive 'noise' is the issue?

 

[tamz]

the radiator closest to the pump makes a masive circulating noise when pump on speed 3, any ideas on what it is?????

You are exceeding the recommended velocity for the pipe size. Set the pump to suit the index which is pretty easy to work out.

 

[CXR100]

yes but when i turn the pump down it starts to make a grinding noise!

 

[diamondgas]

yes but when i turn the pump down it starts to make a grinding noise!

The pump or the boiler? If pump then it may well need replacing ?

 

[CXR100]

i have replaced the pump! its solid fuel!