Boiler aways on Help and information on all topics relating to your central heating, air conditioning and ventilation issues.

[1900munn]

Hi there, can anyone help me. My boiler is on all the time unless i turn it off. I have the room stat turn down. The controls for the heating and the water are both off.

Any idea where I should start looking. :?:

[plumbbob]

Do you have a frost stat?

It could also be a faulty motorised valve.

There are other possibilities, but we are left guessing as we do not know what system you have.

[1900munn]

Sorry about the lack of info. :oops:

I do not have afrost stat.

I do have a Poterton Netaheat Profile 80E

This is working both hot water and 7 rads.

The rads are on one motorised valve

The hot water and tower rail are on another.

I have a Honeywell room stat and a Drayton Tempus Seven timer. :?

So could it be a broken/stuck microswitch on one of the motorised valve

[plumbbob]

This seems like a "S" plan from your description but obviously, it is difficult to be sure.

The most likely culprit is with a faulty zone valve. You say the boiler is on constantly, but are either the towel rail or the other rads constantly heated too? If so it could be a stuck valve. Power down the heating system so it is totally off, and operate the manual lever on the end of each valve and feel if the gears are moving smoothly. If the lever is floppy, the valve is stuck open.

Turn the power on, and with the heating and water set to off, and the fault is present, examine the valves again. If either is floppy, the fault lies elsewhere, if the resistance can be felt, the probability is one of the micro switches in the valve is causing trouble.