I am sure this has been discussed before but can’t find it. Now that I am getting nearer completion my mind has come back to this question . As we all know the COP of an ASHP goes down if the unit defrosts, so as per Others I plan to limit the water temp to about 40 -42 degrees and top up with immersion’s. It occurs to me that the defrost is weather dependant and I was wondering if there is some way for the ASHP to keep raising the water temp till it gets near to defrosting, and then turn itself