Central heating switches on even when its set to off

Question

My boiler has recently been turning the central heating on even when my thermostat is set to off, i have tried changing the min/max temp so that it can only come one if temp is below 10 degrees but it still comes on when thermostat is showing 25 degrees.

Its so warm in my house and obviously its costing me a lot of money and is not very economical.

I have changed the batteries in my thermostat, and at the moment untill its sorted i have actually turned the heating off at the boiler but this is only a short term sollution.

Does anyone have any ideas why it may be doing this?

If you need make/model of boiler i can get it.

Answer 1

I think you should call in a repair man obviously something is wired wrong and only someone who knows what they are doing and is looking at your boiler can help you.

Save yourself money in long run and have someone who knows what they are doing take a look at it

You can always call a few people and get estimates for work to be done then choose who and what price you wanna pay

Answer 2

Most likely faulty room thermostat. The trouble with digital ones is you don't get the audible 'click' that the old pattern rotary types gave. If it clicked it was likely to be ok.

I would replace the 'stat as a first move. After that it is a careful investgation of the boiler wiring to see if you can spot damaged/shorting wires WITH THE ELECTRICITY OFF.

Answer 3

Could be the motor on your zone valve is sticking,see if their is a manual lever and if so push it open and see if it shuts ok,if it doesnt you need a new monitrol motor or zone valve,hope you solve it.

Answer 4

when you say you have turned the heating off at the boiler do you mean you have turned the boiler off .if this is then your problems more lickely to be the diverter valve need more info .also check insurances and credit cards to see if you are covered for a engineers visit.it is only a phone call

Answer 5

Faulty thermostat, definitely.

Answer 6

If the boiler is a combi then the fault will lie with the divertor valve,most combis have a hot water pre heat,so when the boiler is trying to pre heat the water its pumping it round the radiators because of the faulty divertor valve.

If the boiler is a more traditional type then it will be a fault with the zone valve.

Answer 7

When the thermostat is set to off it cannot energize the heating system. If in doubt remove the wires and it should not run.

Maybe some shorting wires or some other control is turning on the boiler.

If your boiler is also used for domestic water heating you may have a defective zone valve stuck on and providing space heating.

Answer 8

to eliminate the thermostat try leaving the batteries out and see what happens