Heating issue

[Mertyn]

Hi gents,

Need your help as i'm at the end of my tether!

Drayton RS1 thermostat
Drayton LP522 Programmer
Drayton MA1 Actuator

I've had an issue where my thermostat has basically stopped working, no 'click' despite the programmer being on.

I've read up and subsequently replaced the thermostat and the three way valve actuator, still no dice...

I've found if bridging the thermostat - wire from live to the call for heat switch - that it works as normal and I can have the heating on, actuator works as normal. This lead me to believe it's a problem with the termostat but as stated it's brand new now and still not working.

I'm out of ideas... what can I try next?

 

[Echo the husky]

How have you wired the thermostat? Any photos?

 

[Mertyn]

Hi, I can get a photo if needed, I basically switched old for new and didn't change the wiring at all. I'd figured that the front unit might have given up the ghost and replaced the back plate whilst i was at it.

 

[Echo the husky]

Photos could be good, I take it the new stat is exactly the same model as the old?

 

[Mertyn]

Yes like for like Drayton RS1, i'll get a photo.

photo here https://goo.gl/photos/fSqsdhNz53VwBojB9

Basically if I put a bit of wire between L and 3 it calls for heat and it works like normal.

 

[EFLImpudence]

Many an hour wasted on faulty new appliances.

 

[eveares]

Can we have a look at the back of the new thermostat what attaches to the wall. There may be something obvious like a pit of protective tape over the conductive pads what make contact with the wall plate.

 

[Mertyn]

Here you go: https://goo.gl/photos/AXSeUxEXFo2BLDVC9

 

[eveares]

Have you tested for mains voltage between the "L" and the "N" terminals on the thermostats wall plate. Use a suitable 2-probe mains tester to do so.

If you don't get any mains voltage between them, then that is why your thermostat is not working. Your thermostat is electronic and requires a permanent live and neural connection to work.

Do you know where the other end of the cable feeding the thermostats wall plate is, and is it possible for you to post a picture of it and what ever it is connected to.

 

[Mertyn]

Have you tested for mains voltage between the "L" and the "N" terminals on the thermostats wall plate. Use a suitable 2-probe mains tester do so.

If you don't get any mains voltage between them, then that is why your thermostat is not working. Your thermostat is electronic and requires a permanent live and neural connection to work.

Would me being able to bridge between the live and call to heat and trigger the circuit suggest that it's working? I don't have a mains tester unfortunately...

Photos of the upstairs, i suspect the thermostat connects into the junction box which the actuator is wired in to?

https://goo.gl/photos/nNA9T31frM3fdjAZ6

 

[Iggifer]

If it worked before, with the wiring exactly as it is, and it works when you short out L and S/L (not recommended btw) then it definitely looks like you've got a duff one or no neutral connection to the thermostat.

The cabling to that stat will be in that junction box, but without a tester, you'll struggle to know what is what. Unless there's an obvious cable fallen out etc.

 

[EFLImpudence]

Have you tested for mains voltage between the "L" and the "N" terminals on the thermostats wall plate. Use a suitable 2-probe mains tester do so.

If you don't get any mains voltage between them, then that is why your thermostat is not working. Your thermostat is electronic and requires a permanent live and neural connection to work.

Would me being able to bridge between the live and call to heat and trigger the circuit suggest that it's working?

It suggests the rest of the system is working but the fault is at the thermostat.

If the Neutral is not connected then the thermostat won't work.
Although, as it worked before and the thermostat is the same this is probably not likely.

 

[Iggifer]

If the Neutral is not connected then the thermostat won't work.
Although, as it worked before and the thermostat is the same this is probably not likely.

True, but a lost neutral could have given the impression of a faulty stat #1 and stat #2 is presenting the same issue because of the same problem.....

 

[EFLImpudence]

Yes, just about to type - it wasn't working before, was it?

 

[Mertyn]

Well, interestingly we've had electricians round recently. As part of the work they did they checked the circuit and noted a neutral leakage which they fixed in another part of the house (replaced a wire between two sockets). Could they have somehow dislodged the neutral whilst testing?