Heating keeps turning off

Postby Ms Boop » Mon Nov 23, 2009 2:11 pm

Very confused - boiler man says its the valve - plumber says its the boiler!

1. Oil fired central heating.

2. Heating set to timed twice a day BUT goes off when it feels like it - although the programmer 'shows' that both heating and water are 'on'...the boiler is COMPLETELY dead. No lights on..no 'lockout' light on etc...and if you push the 'start' button..nothing. SOMETIMES it will start up again on its own!

3. This also happens if both switches for water and heating are set to 24 hours.

4. Motor in valve been replaced.

5. Boilerman says it HAS to be the motorised valve and the whole unit should be replaced.

6. On the valve we've tried taping lever over to the left - so in theory it should be constantly on. However last night heating went off...and valve still over on left!

7. Heating started as per normal this morning - when we checked the lever on the valve its broken free and is now over on the right.

At complete loss here ANY help would be greatly received!
Ms Boop
Posts: 3
Joined: Mon Nov 23, 2009 2:05 pm


Simply Build It

Postby DEEARR2 » Mon Nov 23, 2009 8:16 pm

You say the boiler is totally dead when the programmer is calling for both heating and hot water. If the boiler remains cold during this uncontrolled shut down then you are looking at a control fault. The run signal is not being sent to the boiler. You would be looking at the outputs from your programmer to confirm its operation is not contributing to fault. You will have to confirm where the boiler run signal is coming from ie. Direct from the programmer, via motorised valves, thermostats or whatever.
Should the boiler be hot during this shut down period then the pump should be looked at.
There are numerous possibilities and I would suggest that rather than The Plumber or The Boilerman get a Heating engineer to check it out.
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Joined: Sun Oct 12, 2008 8:49 pm

Postby Ms Boop » Tue Nov 24, 2009 12:37 pm

MANY thanks for your reply DEEARR2! I'm printing your reply out to give to O.H.

In the meantime though - now this MAY sound COMPLETELY :oops: to all your experts out there...but COULD this be the cause???

Plumber suggested - cutting the band securing the thermostat secured to hot water tank..and placing it outside the cupboard. (the hot water tank has one of those moulded surrounds on it and the thermostat is situated towards the bottom and right up against the tank where a hole has been cut into the moulding.

Last night I put heating/water on timed from 19.20 until 23.30 and it stayed on - going off at 23.20. This morning, again it came on for the duration of the 'timed' period. ((shrug)) Going to try putting it on timed for 14.00 until 16.00 this afternoon, to see if it cuts out or stays on in that period.

COULD this be the cause? Could it be the actual thermostat attached to the tank?? :oops:
Ms Boop
Posts: 3
Joined: Mon Nov 23, 2009 2:05 pm

Postby DEEARR2 » Wed Nov 25, 2009 4:12 pm

Sorry I do not understand why the plumber suggests moving the hot water cylinder thermostat from the cylinder to outside the cupboard.

The cylinder thermostat is incorporated into the genareal wiring scheme of the heating control and should only divert the heat from the boiler when the thermostat setting has been reached. However, as you stated earlier the boiler will not fire, on occassion, when you have selected heating and hot water. It would be advised to have the control wiring, taking in the programmer, thermostats and motorised valves checked and proved to be functional.

Interesting that it now appears to be operating on the selected time program.
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Joined: Sun Oct 12, 2008 8:49 pm

Postby Ms Boop » Wed Nov 25, 2009 6:02 pm

We moved the thermostat back onto the tank...having rung plumber..and put both water and central heating on...
left it for couple of minutes then turned it right down to zero.

After about a minute the valve turned itself off but ALSO turned the pump off at exactly the same time..and by all accounts this should not happen...as we still had central heating on timed to be working.

The plumber now suggested we get the heating electrician in because he thinks there is a fault possibly in the thermostat.
Ms Boop
Posts: 3
Joined: Mon Nov 23, 2009 2:05 pm

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