HELP ! Boiler only responds to stat but ignores clock..

[Doddsy]

Gents, having just moved into a new house there is an ideal classic boiler and a Sunvic SP50 time clock. The heating and hw won't respond to the timer.
By turning the room stat up or down the boiler fires or drops back to pilot but it does this regarless of what the timer is requesting ?
If the room stat is turned up above about 20 degrees the boiler fires and appears to attempt to maintain this temp by firing all gas jets and then dropping back to pilot after a while, this on and off continues 24 hours a day unless the room stat is dropped bellow about 20 degrees when it "clicks" and the boilers gas jets go out and it will not refire regardless of what the timer requests.

I would be gratefull for any help

Thanks

I hope i have done this correctly and put it in the right place, if not sorry new to this...

 

[SimonJohns]

Just to clarify

Clock says no heating, thermostat says heat= boiler on

Clock says heating, thermo says heat= boiler on

Clock says heating, thermo says no heat = boiler off

Clock says off, thermo says no heat = boiler off

?

 

[diamondgas]

Doddsy .. initial thought are that your programmer is faulty and ignoring the "CH on/off" switch! Programmers are usually easily removed from there mountings. If you're competent, try removing the programmer and seeing if it comes on then?

 

[Doddsy]

Simon, you are correct thats exactly what is happening.

Steve, it will come on with or without the programmer as long as the room stat is
turned up. If the room stat is turned down the boiler won't spring to life even when
the Programmer requests it, and if the stat is turned up so the boiler does spring to
life then it won't go off when the programmer tells it too.

Thanks again gents..

 

[SimonJohns]

Programmer is broken. Or wiring fault

 

[Doddsy]

Steve, i have removed the timer and without it the boiler goes back to pilot and only
fires when the timer is replaced, but even though the timer is set to HW & CH off at this time the boiler lights and only goes out when the stat is turned down it
"clicks" and turns the boiler off or it appears to go off itself and then refire to maintain
Stat temp ragardless of timer settings. I also can't find a wiring diagram for timmer and system to try to get my head round what should be doing what.

 

[BLOD]

My money's on the programmer being duff

 

[WHPES]

If its been working alright before, one of the contacts in the programmer will be stuck. Replace.

 

[dontknowitall]

I'd say programmer too especially if this a new problem.

 

[fuzzy]

has it always been like this or just started?