Room stat for heat pump

[Norcon]

It doesn't matter what control strategy you deploy. You still have to put the energy in to heat the building and heat pumps eat electricity doing that.

Unless you install them in the kind of homes a candle would heat which lets face it, is the very home the salesmen would like to see heat pumps installed in so they can massage their figures for ROI.

 

[ALEC1]

thats true! to a point! but heat pumps more than any other heat source benefit from compensation controls! as they cannot produce the intense heat needed at the beginning of a heating cycle...

 

[Sultry1]

dcawkwell
I've rechecked all the stat settings and can't find anything wrong. The underfloor system does have a separate pump and blend valve and althogether it works really well - but the stat is non-TPI!

ALEC etc
I suppose to distill it down, the simple question whether TPI control is appropriate in installations which respond slowly, up or down. My own view is that they are not unless there is some aspect of the 'learning' that enables long time constants.

While I have the Daikin controller, it is used only for the heat pump specific controls, for example flow temp set back, weather compensation, etc. it seems to do fine in general.

As I mention previously, I'm aware that the general guidance is to run HPs continuously, but in reality this leads to high energy costs even if you use TRVs. And don't get me started on the marketing blurb that says that HPs are drop in replacements for gas/oil boilers!

 

[richardc1983]

and what do Daikin say about that?

They Daikin engineer who comes to it says it is right.
So why is it 22 degrees in the office and it is set a 19? It seems to have a 5 degree range as default which is far two large. I am not responsible for the installation.

There seems to be no way of controlling it other than getting up
all the time and switching it from heating to cooling.
Set it to self adjusting and we either freeze or are boiled.

The solution is to set the return air temperature so it is sensed at the probe in the controller rather than the actual air con unit.

I had the same problem with my system (non Daikin) When it senses the temperature from the actual unit either mounted on the ceiling or the wall in heating mode it will heat to above 3/4C to allow for heat rising which can give false readings.

If you set it so it senses the temperature from the controller then you will get a 1C differential. EG 19C set it will heat until 20C is achieved and kick back in when the temp drops 1C below the set temp so 18C in your case.