On Monday, 1 March 2021 at 19:16:03 UTC, Peter Able wrote:
On 01/03/2021 11:43, GMM wrote:

the thermostat-controlled bypass

Can you explain this? A bypass of what?

PA
Yes! The cylinder should be controlling a valve. Bypass that I am familiar with have no electrical connection being simple mechanical devices that you set separate on the bypass.