I just hear horror stories locally, enough training isn't here in NI . I would use heat geek if in England.

 

So what if I had the system designed buy someone who knows what they are at and my plumber install it. He is good as a plumber but hasn't the faith in heat pumps. It could change his outlook.

There really is nothing to the design of a heat pump plumbing.

 

Single zone (if you want zones you need a buffer). You need around 40 to 50L of water engaged at all times.

 

Let's say a 6 kW heat pump.

Flexible hose attached to heat pump, then 28mm pipe to a 3 way diverter valve (not a mid point). Normally open port to heating system, normally closed to cylinder heating coil.

 

If UFH either direct to manifold (from diverter) or via a mixer and pump (general it needed.

 

Common return pipe.

 

Heat pump cylinder (3m2 coil).

Here is an image from the Chofu manual

Chofu-Operating-Installation-Manual.pdfby

 

 

 

I largely agree but there are a couple of matters to consider

 

1.  Get the sizing right.  The industry seems, from what we hear (and what I have experienced) tend towards gross oversizing to the detriment of performance for the majority of the season.  

 

2. Decide on the design flow temperature and check the actual output of your candidate pumps at this and your design OAT.  The actual output can be quite different (up or down) to the sticker capacity.