I have recently replaced my old Honeywell ST699 for a ST799. My problem is that the CH works when I only use the CH slider. the hot water doesn't work when I use that slider. also the heating stops working when I use both. any advice would be most welcome.
No hot water.
Dec 19, 2017
4 Replies
Tell us a bit more about the system? i.e. What type of control valve(s) does it have?
Have a look at the following "plans" and see if you can identify yours:
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Have you double checked the wiring at the new controller? Wonder whether the hot water wiring has been done incorrectly?
You are a diicks and I claim my £50
Of course it has.
Nothing else could make that happen
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