Room stat

[AGAS]

Hello all
I'm trying to see if I have a faulty roomstat , can someone advise me please.
When testing for voltage on input and output terminals,on the cover it says this stat is low voltage, so what readings should I be getting ???

Also should these voltages be all voltage or nothing ?.?? Other words if only getting half the voltage you suppose to get does it mean the stat is duff ???

Thank you
Paul

 

[Dan Robinson]

What thermostat is it?

Either way, what goes in one side of the switch should come out the other.

 

[jackthom]

What make of thermostat is it and how many wires are connected?

If there are only two wires connected to it start with the stat set to a very low temperature so it isn't demanding heat.

There will then be a voltage across the two terminals. Don't assume it is a low voltage DC initially. Beware of frying your multimeter by setting it to too low a voltage and then discovering you have mains voltages there!

When the thermostat is set to a high temp it's switch contacts should close and that measured voltage should drop dramatically towards zero if the thermostat is working properly.

 

[AGAS]

Thanks for the replays chaps,
If I remember correct I think it was Rts 5. It is the first one I've seen but looks pretty old, it also has a SAVE button on it aswell
Thanks
Paul

 

[jackthom]

I haven't played with one of those but it may be the optimum start delay feature which is making the thermostat appear to be faulty. It should probably be disabled using the save button for testing.

Terminals 1 & 3 are the ones to connect the multimeter across, to check the switching voltages.

Beware of the mains voltage operating supply connections in there.

 

[AGAS]

Sorry mate but how do you disable using save button for testing,??
One thing I didn't mention it has little neon light in corner when temperature
Dial selected to a temperature you press save button and light stays on.
I only know just enough to get by on electrics so any help would be great.
Thanks
Paul

 

[jackthom]

Sorry I really don't know enough about that thermostat to be certain exactly what the button does.

What sort of problems are you having with the heating?

If it's never coming on there's a quicker way to check out the thermostat.

Make sure the boiler is powered off... then move one of the wires, say the one in terminal 1, to join the other one in terminal 3.

Restore power and then the heating should come on regardless of the thermostat. If it does, replace the thermostat.

 

[AGAS]

When selecting ch only on programmer nothing happens but hw only works fine, when both selected ch comes on only till hw is satisfied then boiler shuts down. I've changed actuator head on mid valve but problem still persist.
So reason for checking R/stat and programmer.
The stat I have never seen before hence the question.
When I get back I will be getting multimeter out, I'm just thinking ahead of what I will be doing.oh and boiler is potterton kingfisher cf 50.
Cheers
Paul

 

[jackthom]

OK I've already added a bit to the previous post about moving one wire so the thermostat is effectively bypassed. That's probably the easiest way to check it and If the heating then bursts into life you need a new thermostat.

 

[AGAS]

Thank a lot jackthom