CH/DHW Systems

Spearmint · Jul 4, 2014

I've been wiring a few S/Y Plans recently and there's one thing I can't for the life in me figure out. What is (or was?) the CH OFF terminal used for on some programmers? I know the DHW OFF terminal is used in a Y Plan setup but haven't seen any other methods that require the CH OFF terminal.

Richard Burns · Jul 7, 2014

I think there are some systems that have valves that are driven open and driven closed (rather than spring return) and then the CH off would be driving the CH valve closed. Might be G plan?
However this is not something I am certain about so do not quote as gospel.

Spearmint · Jul 14, 2014

Richard Burns said:
I think there are some systems that have valves that are driven open and driven closed (rather than spring return) and then the CH off would be driving the CH valve closed. Might be G plan?
However this is not something I am certain about so do not quote as gospel.

Makes sense, I've only come across the driven open ones (not that I'd done 100s).

I really need to login more often...