Heating Wiring Problem - cylinder thermostat not working

[dfreitag]

Hi there,

I've had 4 plumbers & 1 electrician look at my problem (seemingly without dedicating too much time unfortunately), spending more than £1000 already , but none of them has found the issue to my problem - that's why I'm reaching out to you!


I have the below set up

• 1x gas system boiler (Vaillant ecoTEC plus 624 R1) New Pump and New PCB installed rather recently
• 1x UNICYL HE indirect unvented 150L Cylinder
• 1x Cylinder Thermostat (ESI ESCTDEB ESCTDEB Electronic dual cylinder thermostat - https://www.esicontrols.co.uk/esctdeb.html)
• 1x Nest Thermostat (the "learning" type)
• traditional radiators

The Nest controls (or tries to) both heating & hot water.


At the moment the cylinder thermostat is not working - it just doesn't switch on anymore... (it used to only switch on when setting the Nest to boost hot water)

Thinking it was faulty I ordered an identical replacement, and replaced it myself.

By doing so I found the wiring to be rather odd - I have no prior experience at all with these things, so could obviously be wrong..


I am suspecting that someone messed up the wiring at one point.. Can you please have a look?


Many thanks!!


Central Wiring

Cylinder Stat Wiring

Cylinder Stat Wiring Instructions

 

[SparkyChick]

Can you be more specific about where you are in the UK? A local member may be able to help.

 

[SparkyChick]

On reading the thermostat installation instructions, it states quite clearly it requires a permanent power supply. As best as I can tell, yours is only being powered when the Nest is requesting hot water. Given the thermostat has some automation (the weekly legionella killing cycle for example), it could be the constant power cycling is affecting it's operation.

 

[dfreitag]

On reading the thermostat installation instructions, it states quite clearly it requires a permanent power supply. As best as I can tell, yours is only being powered when the Nest is requesting hot water. Given the thermostat has some automation (the weekly legionella killing cycle for example), it could be the constant power cycling is affecting it's operation.

Hi, and thanks for the input!

I thought this was the case..

Is it at all possible to show me how to wire the cylinder stat correctly so that it has permanent power supply, or is this too complicated?
I can't afford to spend even more money on this, so I'd love to avoid a call-out fee for switching just a couple of wires around..

Many thanks!

 

[dfreitag]

Also, to clarify - the way it's wired rightnow the cylinder stat NEVER goes on - not even when the Nest tells it to..

 

[SparkyChick]

Also, to clarify - the way it's wired rightnow the cylinder stat NEVER goes on - not even when the Nest tells it to..

So that suggests the wiring in the Nest is also bad. A photo of the Nest connections may help.

 

[brianmoooore]

Is the black from the 'stat taped off at the wiring box? If so, the 'stat isn't getting a neutral.
There are a few things that need addressing with this installation - not least that the cable clamps for the wiring box haven't been broken off from their resting place and used to actually secure the cables.

 

[SparkyChick]

Is the black from the 'stat taped off at the wiring box? If so, the 'stat isn't getting a neutral.
There are a few things that need addressing with this installation - not least that the cable clamps for the wiring box haven't been broken off from their resting place and used to actually secure the cables.

Good spot... missed that

 

[dfreitag]

Is the black from the 'stat taped off at the wiring box? If so, the 'stat isn't getting a neutral.
There are a few things that need addressing with this installation - not least that the cable clamps for the wiring box haven't been broken off from their resting place and used to actually secure the cables.

Many thanks for the feedback

Exactly!! The black one is connected to the stat and it goes nowhere in the wiring box..!

Excuse my ignorance, but which cable clamps do you mean - and how can I correct this?

Also, sending a photo of the wiring at the Nest

 

[dfreitag]

Can you be more specific about where you are in the UK? A local member may be able to help.

sure, London E5