Hello all,
A few days ago I was woken up by some strange noises coming from my central heating system. They sounded essentially like boiling water, so my first reaction was to race downstairs and turn the system off.
My first assumption was maybe a sludge build up - looking at the header tank (this is an open vented system) showed a fair amount of crud, so I got that out, then drained the system down and refilled (remembering to add some inhibitor).
This unfortunately didn't solve the problem - my next thought therefore was perhaps the pump was struggling, and thus the water was not being moved round the boiler quickly enough - as such I decided to replace the pump (the previous one had been in since before I bought the house). Having just done that, unfortunately the problem still hasn't gone away - I suspect I'm going to have to call in a professional, but before I do I thought I'd see if anybody on here had any bright ideas as to what's wrong.
I thought I'd go through the most recent example I've had of the problem:
After fitting the new pump, I refilled the system (including bleeding all the air out the radiators), and left it running with the pump only for a while on both hot water and central heating.
I then turned the boiler on, and everything seemed to be going OK (the radiators heated up etc). As it was quite a warm day, I then turned the radiators off (the system has a 3-position valve), and again initially all seemed fine.
About 5 - 10 minutes later, I heard the boiling noise again. I immediately turned off the boiler (leaving the pump on), and almost immediately after that I heard a loud pipe banging noise for a few seconds, and then the system calmed down.
My thoughts are that either there is a large piece of crud that is going through the system and it occasionally gets stuck somewhere causing the noise, or that something is up with the boiler thermostat and it's not cycling like it presumably should do, so is overheating the water in the pipes.
In terms of other components the motorised valve was replaced a few months ago as it siezed (would not fully shut off the central heating), so I doubt that is at fault, and the programmer seems to be doing what I would expect etc. Checking the thermostat on the hot water cylinder that seems to switch off if I turn the temperature down considerably.
Any suggestions of things to try before I call in the plumber to check the boiler etc most welcome...
A few days ago I was woken up by some strange noises coming from my central heating system. They sounded essentially like boiling water, so my first reaction was to race downstairs and turn the system off.
My first assumption was maybe a sludge build up - looking at the header tank (this is an open vented system) showed a fair amount of crud, so I got that out, then drained the system down and refilled (remembering to add some inhibitor).
This unfortunately didn't solve the problem - my next thought therefore was perhaps the pump was struggling, and thus the water was not being moved round the boiler quickly enough - as such I decided to replace the pump (the previous one had been in since before I bought the house). Having just done that, unfortunately the problem still hasn't gone away - I suspect I'm going to have to call in a professional, but before I do I thought I'd see if anybody on here had any bright ideas as to what's wrong.
I thought I'd go through the most recent example I've had of the problem:
After fitting the new pump, I refilled the system (including bleeding all the air out the radiators), and left it running with the pump only for a while on both hot water and central heating.
I then turned the boiler on, and everything seemed to be going OK (the radiators heated up etc). As it was quite a warm day, I then turned the radiators off (the system has a 3-position valve), and again initially all seemed fine.
About 5 - 10 minutes later, I heard the boiling noise again. I immediately turned off the boiler (leaving the pump on), and almost immediately after that I heard a loud pipe banging noise for a few seconds, and then the system calmed down.
My thoughts are that either there is a large piece of crud that is going through the system and it occasionally gets stuck somewhere causing the noise, or that something is up with the boiler thermostat and it's not cycling like it presumably should do, so is overheating the water in the pipes.
In terms of other components the motorised valve was replaced a few months ago as it siezed (would not fully shut off the central heating), so I doubt that is at fault, and the programmer seems to be doing what I would expect etc. Checking the thermostat on the hot water cylinder that seems to switch off if I turn the temperature down considerably.
Any suggestions of things to try before I call in the plumber to check the boiler etc most welcome...
