Help! CH on constantly.

[Roo]

I don't know anything about Central heating and hoping somebody could help.

Before I start I do have plumbing and heating cover from Homeserve but before I call them out I want to check the problem is more to fix than Homeserves £50 excess.

I believe I have a conventional boiler setup not a combi etc?

I have an Ideal Elan 2 boiler, a Randall TP5 electronic programmable room thermostat, hot water tank upstairs and no cold water tank.

The Room thermostat controls the CH only, with the hot water temperature adjustable on the boiler.

We have the Room stat set at 5deg unless we want any heating on in which case we set the temp higher.

THE PROBLEM!

Over the weekend we heard the room stat click as if the room temp had dropped below 5degs and the radiators then started to warm up.

Although we don't have a thermometer in the house, the car was displaying 14degs later on when we went out.

The Central heating has now stayed on constantly and the only way to turn it off is by turning the boiler off, which in turn also turns the hot water off.

Could it be I have a dodgy Room stat?

Is there a way to test it?
ie. Can I just simply remove the stat and see if the CH pump is still whirring away?

I've had a quick google and it seems you can pick them up fairly cheap but don't know if they will all work with my boiler?

If it doesn't sound like the room stat is there anything else it might be that I could check before calling the Homeserve chap/chapess out?

Thanks

 

[ChrisOxford]

Could it be I have a dodgy Room stat?

Is there a way to test it?
ie. Can I just simply remove the stat and see if the CH pump is still whirring away?

If I were faced with your problems, I would indeed disconnect the room thermostat.

Do you understand electrical wiring? Bear in mind that these work at mains voltage which is potentially lethal, so you must be able to isolate the mains supply before trying anything.

Have you got the instruction booklet for the thermostat? It's here: http://heating.danfoss.com/PCMPDF/022.pdf

Isolating the wire from terminal 3 should prove the point, BUT only do this if you're confident with mains electricity

 

[Agile]

First time I have heard of a Homeserve £50 excess!

 

[Roo]

Could it be I have a dodgy Room stat?

Is there a way to test it?
ie. Can I just simply remove the stat and see if the CH pump is still whirring away?

If I were faced with your problems, I would indeed disconnect the room thermostat.

Do you understand electrical wiring? Bear in mind that these work at mains voltage which is potentially lethal, so you must be able to isolate the mains supply before trying anything.

Have you got the instruction booklet for the thermostat? It's here: http://heating.danfoss.com/PCMPDF/022.pdf

Isolating the wire from terminal 3 should prove the point, BUT only do this if you're confident with mains electricity

Thanks Chris,
Mrs Roo was whining last night so I got the tools out.

Turns out it was the room stat, and after removing it the CH pump shut up and the radiators didn't warm up but we still had the hot water.

I've fitted a 20A switch temporarily so I can still have hot water and turn the heating on and off if needed until I get a new room stat.

Thanks for your advice.

@ Agile I signed up nearly a year ago so I can't remember all the Tand c's but their site suggests it HERE under the whats not covered bit.

 

[bell824]

First time I have heard of a Homeserve £50 excess!

yep another ploy to get cheaper insurance cover, if B.G can doso can all the others eh blooming typical!!!