Testing power at thermostat

[dk1uk]

Hi, I need to test whether a thermostat is getting power. The thermostat is for underfloor heating in the kitchen. I know the thermostat itself is not faulty because I’ve tried swapping it with the one in the hallway and it worked fine.


Therefore I’m assuming the fault is elsewhere, possibly a wiring issue stopping power getting to the thermostat or maybe the back panel to which the thermostat is attached.


All of the thermostats are connected to the Heatmiser UHF8 8 zone box - having taken the cover off that, the wiring looks sound. So I I wonder if there’s a problem between the box and the thermostat hence the need to test the power,


I have a multimeter but I’ve only ever used it for continuity testing, can anyone help (really simple instructions based on the pictures I’m providing)?


Thanks

 

[chivers67]

Brown and Grey should in theory have voltage, so place the dial onto 500V and see how much by placing the probes on those wires. If no voltage test across the brown and black.

Switch the top to left AC

 

[dk1uk]

Thank you and sorry for the basic questions, but:

1. I should have the power turned on right?
2. AC is the V with the squiggly line?
3. Does it matter which colour probe I have on which colour wire and should I place them on one after the other -if so which first?

Thanks

 

[chivers67]

The switch at the top on V with squiggle above it denoting AC.

The power needs to be on otherwise there will br no voltage present. Red to Brown (L) and Black to Grey (N). The Grey wire should be blue sleeved or at the very least have a bit of blue insulation tape on it btw

 

[dk1uk]

Super thanks, voltage says 239. So it’s getting power and yet the display isn’t coming on - but if I swap it with the one in the hallway it works - strange? I’ll try swapping the thermostats back panel too and see what happens. Thanks again.

 

[dk1uk]

The back panel is faulty, swapping one over from the kitchen to the hallway and it works fine. I’ll just need a replacement. Thanks again for your help!

 

[ericmark]

I would assume hot water system as no connection to RT, so you should be able to hear the valve open and close. If electric then normally you have an under floor sensor to stop floor over heating connected to RT.