Heating with its own mind

[smiffy1956]

I woke up to what i thought was a hot flush but only to find out that my heating had decided to come alive with all the rads in the house red hot i checked the room stat only to find that it is on zero?? i turned it to 20c and then back off and there is a definate click the heating did appear to go off . I have checked the controller in the airing cupboard and both switches are set to heating and water accordingly (not on timed) the heating and rads have come alive once more since this but all cool now. My boiler is a Baxi Solo....I did the other day flick the heating on for half an hour or so and this is the first time since early this year Any ideas

 

[Nixt]

If you have a Y-Plan (eg. 1 mid position valve) it could be faulty passing to the heating and then cools only when cylinder stat is satisfied.

 

[smiffy1956]

Y Plan ??? Do you mean the motorised valve that calls between heating and water ?? with the PCB fitted in the silver box or otherwise .....i do have a 3 position switch on the controller in the airing cupboard IE Timed/off & heating and this is set to heating and on the opposite side a 3 position switch with timed/off and water which is set to water

 

[Nixt]

The motorised valve. To test (without intruments) activate for heating and hot water (on timer as usual) then turn your room stat on fully. Then turn your cylinder stat off, if the boiler cuts out and does not respond to the roomstat call for heat the motorised valve motor head is faulty. If it does respond turn the roomstat down to off if heating continues r/stat might be at fault. Turn your roomstat off and cylinder stat back to original position.

 

[ChrisR]

One of these he means, with the 3 pipes going in to it:

 

[smiffy1956]

Thanks for all the great info will check it out tomorrow and let you know.........I did replace the PCB within this valve some 8 years ago or so

 

[Dan Robinson]

I did replace the PCB within this valve some 8 years ago or so

Well it must be ok then...

 

[smiffy1956]

Switched room thermostat on and boiler called for heat.....Turned tank stat off then turned room stat off boiler cut out.......Tried several times and boiler always cut off...All seems to be OK now perhaps the valve was sticking after such a long time for not calling for heat ???.......Thanks once again for pointing me in the right area