Boiler Wont Come Back On After Thermostat Change

[Chris1875]

Hi, hoping someone can help. I have just removed my Nest thermostat to put the original Danfoss rmt230 thermostat back on. I've wired it up the same as it was before but now the boiler wont come back on! I have changed the fuse on the boiler but it made no difference. Thanks.

 

[Sharpend]

Oops! Have you any pictures before and after or possibly just after? 

 

[Chris1875]

Oops! Have you any pictures before and after or possibly just after? 

Hi, can't work out how to add a picture to my post so I've uploaded it to here: https://drive.google.com/file/d/1Wcj5qOPqGPmJ1768YhgbVAtCqFJGnWTB/view?usp=drivesdk

 

[Andy™]

why did you replace the fuse? if it was blown then its blown for a reason, quite possibly wired wrong, and replacing without fixing the fault wont help. if it wasnt blown then replaceing it makes as much difference as replacing a door handle to try and get the boiler working again...

 

[SPECIAL LOCATION]

What test equipment do you have access to?

i.e.  to measure Voltage & Continuity?

With suitable testers, it would take probably less than 15mins to verify if power is present..

if the thermostat is switching,

and if the cables are connected the correct way round..

Its generally best not to try guessing which wires are, Live, Switched live and Neutral..

when using devices that switch 230v

Is your picture the ONLY way you have tried connecting the thermostat?

Or did you try it another way first that blew the fuse?

If you did blow the fuse by wiring it incorrectly and putting a dead short across the thermostat terminals..

you could possibly have damaged the thermostat..

My first steps would be to disconnect the wires..

Then:-

[1] Verify that the thermostat contacts are still switching when you adjust the dial temperature up/down..

[2] Verify the supply polarity across the Brown/Black & grey wires..

[3] Verify that the boiler fires up with a temporary connection between the Live & Switched Live..

My only other thoughts would be...

Why were you removing the Nest thermostat in the first place.. 

And did it still work the boiler before you disconnected it?

OR.. Is there actually a boiler fault that you thought was the Nest..?

The photo you uploaded is only really useful if you also have an original photo as well to compare with.

Guinness  

 

[Adam Stanley]

This problem can either be due to a faulty wiring or a damaged component on your thermostat. And possibly you have damaged the thermostat by blow the fuse by wiring it incorrectly. In all 2 cases, you need to be access the inner components, so get ready to open your thermostat and call to a trained engineer.

 

[SPECIAL LOCATION]

 so get ready to open your thermostat and call to a trained engineer.

Doubt you will be able to find many "trained engineer's" who look at domestic heating controls...

:C