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Andrew Smith
Andrew Smith, Plumber
Category: Plumbing
Satisfied Customers: 3756
Experience:  City and Guilds qualified plumber
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Central Heating Boiler Issue - Banging pipes and Overheating

Customer Question

Hi, I would greatly appreciate some advice. I'll try and give as much detail as poss, whilst trying to keep it short. Boiler: Barlo Balmoral 55F, approx. 15 years old (not Combi type). Pump: Circulation Pumps Ltd CP53 fairly new. PCB and Solenoid 1 year old. Problem: Overheat thermostat tripped and so I reset and fired up boiler. Boiler appears to work as usual, however loud popping/banging of pipes from boiler up to where pump is located. Inconsitent hot/cold flow of water passing through pipe near pump. After less than 1minute, boiler overheat thermostat trips out. What I've tried so far: System was fully flushed by me and an engineer when I moved in 18months ago, with chemicals. Pump seems to be rotating fine having inserted screwdriver. I have tried bleeding pump and all radiators to no avail. FE tank is full and ball float (excuse my lack of technical terms) is working as it should, so have (maybe naively) ruled out excessive air intake into the system. Going forward: I have read on another topic, that the heat exchanger may be faulty or blocked causing kettling of boiler and may need descaling. Does this sound like the most likely cause of my problem? I'm assuming a faulty thermostat or overheat thermostat is not the issue, as the pipes are banging and boiler only runs for 1minute before tripping out. Any advice or help would be greatly appreciated!



Edit:  Also, about 1 week prior before the boiler issues, the toilet cistern was very erratic in refilling. It seems ok now, but could this be related to a blocked cold water feed and therefore lack of water in CH system?  Many thanks.

Submitted: 4 years ago.
Category: Plumbing
Expert:  Andrew Smith replied 4 years ago.

Andrew Smith :

If the pipework is banging then the water in the boiler is boiling, there is a circulation problem

Andrew Smith :

Can you prove the pumps is actually spinning when it is supposed to be?

JACUSTOMER-nbg4z3w4- :

Hi, thanks for your reply. the pump vibrates when the CH is on which has lead me to believe that it is working. Is there a way of finding out whether the pump is turning correctly? If I ascertain that it is not the pump that is the problem, and there is a blockage within the pipes which is preventing correct circulation, how could I go about finding its location and remedying it? many thanks!

Andrew Smith :

The idea is to follow the heat

Andrew Smith :

Turn the boiler and heating on and see how far the heat travels along the pipework, from cold it should travel about 1ft a second depending on the pipe size