Thermastat problem (?)

[Jonnyboy17]

Model Drayton (looks like RTS1)
Boiler - ideal Classic LXFF
timer - Drayton Tempus Three

Problem - boiler will not shut down at end of timed period. I've tried all the options on the timer panel, but it seems like it is being by-passed by the stat, eventhough the stat doesn't appear to have power to it at that stage (doesn't click)

During the heating period the 'stat clicks, but I'm not convinced it controls the temprature.

To solve the problem, I have to switch the timer back on, then manually turn down the 'stat (clicks off). When I switch the timer off - then the boiler will shut down.

(The system has worked ok for the last four years)

Question - is it as simple as a knackered 'stat? If so, could I replace like for like myself (status - moderately experienced DIYer).

Ta Jonny

 

[D_Hailsham]

Problem - boiler will not shut down at end of timed period. I've tried all the options on the timer panel, but it seems like it is being by-passed by the stat, eventhough the stat doesn't appear to have power to it at that stage (doesn't click)

If it is wired correctly, the timer cannot be bypassed by the stat as the stat receives power from the CH ON terminal of the timer. So, when the timer is off, the L terminal of the stat should have no voltage.

During the heating period the 'stat clicks, but I'm not convinced it controls the temperature.

Does the boiler light when you turn the stat up and stop when you turn it down?
Is the stat wired correctly? Neutral to N; Live from Timer CH ON to L; Terminal 3 to boiler/zone/mid position valve.


It sound more like a problem with the timer - not turning off when it should.

 

[Jonnyboy17]

Thanks for your reply.

The stat generally(!) appears to work as it should - boiler responds by starting up/shutting off as expected.

BUT the reason I'm unconvinced about the stat though is that the first problem I had was that during a heating period the boiler just kept burning whatever I did with the stat which was clicking on/off (I controlled it eventually by turning the boiler dtat down.)

The timer seems ok - I've tried running through the options and it responds correctly to the various settings.

The timer will turn off the boiler IF the stat is in the closed/off position; if it's open/on the boiler just keeps on running...does this help?

 

[D_Hailsham]

How many motorized valves do you have?