Thermostat not working

[KNIPEX]

Hi all, was called today to have a look at a faulty thermostat, however i havnt done any central heating systems before thereb were no drawing present was so was slightly baffled (quite embarssed tbh)

anyway i tested for power they was power there, could the stat be faulty??

the guy said he had tampered with it aswell which confused the issue even more, so could someone tell me what the connections should be what i should be testing etc.

im after all help please

thanks

 

[stef]

Hi Knipes,

there must be a N/O contact on the thermostat connected to the GCH. On the Boiler it could be labelled
as 'external on' or soething like that. Put your continuity tester on the N/O contacts on the thermostat
and turn the knob (or whatever is used to control the themperature) and it should switch. If it doesn't:

Check whether there a timer function included? Make sure the timer is on.

Short the contacts out and the GSH shoud fire up.

 

[KNIPEX]

Hi Knipes,

there must be a N/O contact on the thermostat connected to the GCH. On the Boiler it could be labelled
as 'external on' or soething like that. Put your continuity tester on the N/O contacts on the thermostat
and turn the knob (or whatever is used to control the themperature) and it should switch. If it doesn't:

Check whether there a timer function included? Make sure the timer is on.

Short the contacts out and the GSH shoud fire up.

thanks for that m8 what is GCH and GSH??

Keep the help coming please guys.

 

[Guest123]

Does sound like a faulty stat as you say ther's power to it but it's not switching.

Can you remove the L and SL from the stat put them in a connector then switch the power back on and the boiler should fire up.

A continuity test between the COM and N/O and N/C terminals on the stat will then confirm if it's good or not.

 

[bugsy]

If it's not the stat check the boiler stat ( heat overload stat actually in the boiler ) if there ok check the three port valve
( if there is one )