Banging Pipes

[willing2learn]

Hi, got a call from a friend who said her central heating pipes make banging noise at night mostly when she shuts her boiler off. Went over earlier and had a look, she has an ideal isar (i think!) and a combination type cylinder with the built in header tank. I had a listen to the banging and decided it's not emitting from the boiler itself. Had a look in the airing cupboard and checked the pumps, there was 2, one labelled for heating, the other for the boiler. The heating pump seemed to be working fine, I tried lowering the speed on it to see if this would cure it, but no joy. Now, the other pump labelled 'boiler' looks a bit worse for wear, furred up etc (will probably replace this). I tried turning this pump down, but noticed it didnt change speed when I move the lever. I could feel it still whirring though.

Do you think the 'boiler' pump is shot and could be cause the banging?

I've got to go back later in the week to connect up a new rad in a garage conversion, so will be draining the system then anyway and having a few floorboards up to add to the pipe work. So I'm going to listen to the pipes with the boards up in the area I'll be working in.

Do you think the pump needs replacing? Or could it be a case of it becoming unclipped somewhere out of sight? I was going to take a bottle of noise reducer with me with the inhibitor too.

Any views?

 

[Puddle]

Sounds like some make of thermol store cylinder,should have the make on it
If so the pump over run may be controlled in unit and not boiler,possible faulty pump over run board

 

[willing2learn]

Sounds like some make of thermol store cylinder,should have the make on it
If so the pump over run may be controlled in unit and not boiler,possible faulty pump over run board

Hi, the cylinder is similar to this one....
1050 x 450 Combination tank indirect : Cylinder Store UK, unvented cylinder | thermostatic shower | immersion heater

apparantley it's not that old, but as already mentioned, one of the circulating pumps looks very tired and didn't respond to the speed lever changing.

 

[Billy Bob Bob]

eliminated pipe hammer?

 

[willing2learn]

eliminated pipe hammer?

it's not very loud/violent, and only happens when boiler is turned on or off.

 

[Billy Bob Bob]

if its a low water content boiler the boiler would be kettleing as well,be very carefull about changeing the pump on the thermal store gledhill for example use a special grundfoss low voltage pump that can not be replaced with a standard
grunnie and if its this manufacture trying to alter the pump speed wont make a difference think you need to find out more info on what you have fitted in that job

 

[willing2learn]

if its a low water content boiler the boiler would be kettleing as well,be very carefull about changeing the pump on the thermal store gledhill for example use a special grundfoss low voltage pump that can not be replaced with a standard
grunnie and if its this manufacture trying to alter the pump speed wont make a difference think you need to find out more info on what you have fitted in that job

OK, thanks for the heads up, will have a closer look when I go out there later in the week.