Central Heating

[NONREV]

I have Worcester boiler that has suddenly stopped heating my radiators, the hot water system is working fine.Could this be due to the pump is not working so that the water is not being pumped around the heating system. Is there any way that I can check this out and fix it my self.Thanks for any help. NONREV.

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[bhg481]

Central heating systems are normally desiged such that the hot water is heated to the set temperature (there is a thermostat on the hot water cylinder) before the radiators are heated. Once the hot water is up to temperature a diverter valve sends the water from the pump to the radiators instead of through the hot water cylinder. This diverter valve can fail (mine did several years ago) so the water doesn't get diverted to the radiators. It's a simple thing to fix and shouldn't need the system draining if the installer put isolator valves round it.

[bhg481]

I should have added that these are the sort of thing you are looking for - you will notice that (If you're lucky) you may be able to change just the activator and save yourself some money.

http://www.screwfix.com/c/heating-plumbing/motorised-valves/cat831028

[NONREV]

Thank you for a great answer to my question on radiators not working,I do have isolators valves fitted but don't know where to find the divertor. or activator valve.I may try what you have advised if I feel confident myself or ask my son in law to look at it.BUT THANK YOU SO MUCH.

[bhg481]

If you look at my link to Screrwfix you will see what the valves look like. Normally a pipe comes from the boiler into the airing cupboard and into the pump. The output from there goes into the activator valve, which has 2 outlets; one branch goes into the hot water cylinder and the goes off to the radiators.
The activator valve has an electric wire connected to it which comes from the central heating control system.
I should mention that I have described what used to be a conventional system, the only one with which I'm familiar. If you have a combi-boiler it MAY be a bit different - I just don;t know.
Good luck.

[NONREV]

To bhg 481 Thank you once again for your help, I have been upstairs taking the back off the boiler and missed your second answer.however I will have another look and report back. THANK YOU FOR YOUR HELP----NONREV.

[mikey4444]

This happened to me late last year, and it was the pump not working.

A plumber friend of mine hit it very hard with his Stilson, it started up, made a lot of noise and is now perfectly OK !

Check that the pump is coming on before you call in professional help. When you press the "heating constant" control ( or similar) the pump should start up within a few seconds. If it doesn't, that is your problem !

Let us know how you are getting on.