ASHP defrosting question

[Eileen]

FYI, if it’s a useful case study for anyone, it’s just gone into a ‘normal’ defrost right now at 12.48, outside temp 7-8C, now doing its thing trying to get the PHE temp back to where it was. When it’s in this mode it drops back before it ever reaches the required temp (we have set it to 45 since the original 36 made zero impact on the room temperature). If we’re lucky it will reach 35 before it defrosts again, on repeat, so makes no dent in the room temp. 

 

[SteamyTea]

@Eileen

Is it actually defrosting, is the unit actually showing ice on the coils?

 

does your system have a buffer cylinder?

[Eileen]

There was a just slim line of ice down one side a bit earlier. The PHE temp had already reached about 36 from about 26 before the defrost started, and the outside temp was good, so I thought we were all good to continue and get up to 45.  Yes, i think we have a buffer cylinder,  I remember we had an extra £1000 worth of plumbing a year ago in our attempts to get a solution,  which I believe was adding a buffer cylinder. That fixed an error code we were getting. I’m pretty sure it was defrosting because the little snowflake symbol was presenting on the main display of the ashp. It only last a few minutes so I don’t see it unless I’m standing there forever, but I was triggered to go and check because the house power consumption went down to about 1.44 instead of the 2.58 it was previously running at, yet all thermostats were still calling, so I knew none of rooms had reached temp and turned off any pumps. The refrigerant temp had dropped sharply to -7.6 from 36 by the time I got  to it, then the snowflake symbol went off and the refrig temp started rising again