Central Heating making fuse box cut out?

Postby TracyB » Wed Oct 22, 2008 9:09 am

Please excuse my lack of terminoligy but hopefully you'll understand my problem and be able to offer a solution?

A few weeks back I came home to find no hot water or heating - went to my programmer and there was no power and the main fuse for the heating was off.
I flicked it back on but it immeadiatly cut out again. I changed the fuse in the box between the main fuse box and programmer - no change.
Realised that when CH was turned off the timer worked fine but soon as I asked the programmer to turn on the CH it blew the main Fuse.

I thought it may be a wiring problem behind the programmer so took the programmer of the wall but the wiring looked fine. The programmer itself looked like it had seen better days and the light for the CH indicator never worked since I moved here (8 years) so I though that the CH part of the programmer had finally had it.

Brought a new programmer - like for like - and this morning plugged it in HEY PRESTO! CH Light comes on, Boiler fired up for a couple of mins and me a happy girl :lol:

Wrong!!!! Turned my thermostat up and the heating cuts out again. This only happens if I turn my Thermostat above 15 degrees. So now I have the programmer working - I can hear the boiler responing every 5 mins or so but I can't have the heating above 15.

I know I've rambled but wanted to give you a full picture of whats gone on.

Any ideas where the problem lies? Do I need a new thermostat? It is a old mechanical one.

Thanks in anticipation x
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Joined: Wed Oct 22, 2008 8:47 am


Simply Build It

Postby htg engineer » Wed Oct 22, 2008 6:25 pm

Renew pump, when you turn the room thermostat to above 15 degrees the pump will come on, tripping the electrics.

To test, turn thermostat up.
Select HW only - works ok ?
Select HW and CH - trips ? pump at fault.

Assuming you have a gravity hot water system.

htg engineer
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Joined: Tue May 22, 2007 5:22 pm

Postby TracyB » Wed Oct 22, 2008 6:40 pm

That sounds like the problem then - do you know roughly how much that will cost me to get repaired - sounds like something I won't be able to attempt myself!

Just a seperate query that may or may not be linked??

I havn't had a functioning shower or bath taps for about a year as no hot water comes through and very little cold (both run off the same mixer valve) (been filling bath from sink tap in case your wondering!!) - when 1st installed about 24 months ago the power was very weak anyway and I was told to get a better pump as there wasn't enough gravity pull. Is this the same pump we're talking about? If so I can kill 2 birds with 1 stone (fingers crossed!!!)
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Postby Steve the gas » Thu Oct 23, 2008 4:36 am

Hi Tracy,

As Htg says- get a man/woman in to fix it - show them this thread-- saves time.

Good luck
Steve the gas
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Joined: Sun May 04, 2008 7:07 am

Postby htg engineer » Thu Oct 23, 2008 9:28 am

No, i'm talking about your central heating pump. You're talking about a pump for hot water. Not normally needed unless you have a shower fed from stored cold and hot water.

If you take the DHW pump out, your bath and sink taps pressure will be fine, it'll only be the shower that you will see a decrease in pressure - but you could fit an electric shower.

Sounds like both pumps need replacing, get a plumber out. It's also quite easy for a competent DIYer - you know your own limits, any doubts get a plumber out.

htg engineer
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Joined: Tue May 22, 2007 5:22 pm

Postby TracyB » Thu Oct 23, 2008 10:30 am

Cheers for that - will get someone out.
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Joined: Wed Oct 22, 2008 8:47 am

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