Room Thermostat not working

[spice28]

Hello,

I hope someone can help me.

I have an Ideal Mexico 2 gas boiler. It's quite old but we have never had any previous problems before now.

Basically the boiler has stopped responding to the room thermostat. The boiler comes on every morning and evening on the timer, both the hot water and radiators are heated, but once the hot water reaches the desired temperature the boiler switches off even if my room temperature is well below the thermostat setting of 19 degrees.

If I press the 'advance' button nothing happens, the boiler does not ignite. If then I have a shower and subsequently hit the advance button for the central heating the boiler will start and heat both the radiators and hot water again for a short time until the water is heated before switching off again.

Do you think that it's the thermostat that's broken and if so should I still get the boiler checked? Does a boiler repair person fix faulty thermostats too or do I need an electrician? Is this going to be a costly business?

Thanks very much for your help!

 

[freeflow]

sounds like a faulty microswitch or actuator on the central heating zone valve,or a partially seized ch zone valve body.

 

[spice28]

Hi freeflow,

Thanks for you comments. Do you know if that would be expensive to fix?

Thanks again

 

[MANDATE]

You need to confirm what type of motorised valve or valves are in your system. I've had exactly the same problem with a 3 port motorised valve.
Checks proved the valve was moving as it should, which proved the room stat and the wiring were ok. There being no output on the orange wire proved microswitch faulty. A replacement actuator head cured the problem, cost about £45 to purchase

 

[spice28]

Hi Mandate,

According to the boiler manual it looks like a: 1/2in. BSP Honeywell compact gas control V4600A 1023 240v.

Thanks for your help.

 

[freeflow]

forget looking in the boiler manual, the gas valve that you are stating is NOT! the problem with your system.
the motorised valves will normally sited next to the pump.

 

[spice28]

All sorted now - the valve (3 port motorised) isn't working properly and so a new one is on the way.

Thanks to all for your help!