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Nov 23, 2022
1
0
1
Oxfordshire
Member Type
DIY or Homeowner
Hi,
I'm brand new to plumbing, heating systems, wiring etc and only started to read about it because I wanted to know why our CH would only work when HW was also on.

I think we have a Y system based on the Honeywell 3 position diverter valve above the boiler. We have a Potterton EP2002 programmer and I've attached photos of the wiring. This doesn't look like the wiring diagrams I've found on the Internet, can anyone make sense of it? I'm fairly sure there's no HW Off wire, could this be why CH only works with HW on?

I'm looking at getting a Nest Learning Thermostat, would it be compatible with current system do you think?

Thanks in advance for any help you can provide. I'm sure I'll end up getting a specialist in but I like to at least understand these things!
 

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