Figures fluctuated slightly, heating is currently on

Posted by: @jgtukpd

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0= 31

1 = 60

2 = 52

3 = 5100

4 = 600

5 = -4

6 = 2 

7 = 4400

8 = -3

9 = 41

Okay, you have displayed the following information

 And it tells me you are using 5kw (#03) at this time. With a flow temp of 41°c (#09) and a return of 31°c (#00)

That's very high, but before anyone makes changes, there are a couple of questions to ask

1/ is the house comfortable, too hot, too cold?

2/ do you just have the one thermostat controlling the system and where it it located ?

3/ do you turn down any rad / ufh when its on ?

The house is slightly chilly for most people, could be warmer.

One thermostat for upstairs and another for downstairs both set to 18 degrees

Only have rads, some turned down (TRV) in smaller rooms but larger rooms feel colder

Thank you for that, I would have expected the system to be running a lot less than that and does imply there may be a problem.

Sorry to ask, but it will help. You say its a Stone house, 5 bed. Are these solid walls, no air gap, and/or little insulation ?

Do you know your house heat loss ?

As the HP has a high flow temp and you had rads changed they should be warm to the touch (ie they are not too hot like gas boiler, but not cold to the touch) ?

I would say they put a buffer in with 4 ports. One side connects to the HP, the other to the CH ? If so, can you feel the two top pipes. I suspect the HP side will be warmer than the CH side (if possible test will thermostat and register the temp)

It's a large 5 bed. Stone and some brick, all external walls were insulated from the inside. Good loft and ceiling insulation.

I don't know the heat loss.

Rads are warm to hot, not as hot as our old oil fired system.

Is this the buffer?

@jgtukpd yes that looks like it. The size indicates a low loss header.

The left goes to the HP, the right to the CH (?). If correct, then there is the one pump for the CH and two pipes ( right side bottom), come back from the two zones you have.

Feel the two pipes at the top.

Note. Forgot to say, on the controller press the Return key till bleep and the display will go back to normal.

Heat energy being thrown away.

Pipe insulation needs re-doing so that it seals around all open metalwork.

See this article.

With ch running, hp side (rh top) is reading hotter than ch side (lh top). 
Using a cheap led thermometer they’re reading a couple of degrees apart (37.2 degrees and 35.1 degrees)

Posted by: @jgtukpd

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With ch running, hp side (rh top) is reading hotter than ch side (lh top). 
Using a cheap led thermometer they’re reading a couple of degrees apart (37.2 degrees and 35.1 degrees)

Interesting, the pump on the right (of the photo) is normally inside the HP and another one is not needed inside the house. 

Also there is a big drop from the flow out of the HP (#09 @ 41c) to 37.2c, it could be the thermostat itself though.

Okay, from the information we have, though the reading don't quite match it up I suspect the following 

The HP and settings have been installed, as Grant send them out. The HP pump is set as high (#07 4400) and I suspect you are running just flow temp and not WC.

This means all your heated water is being sent back to the HP and not into your CH. It does means with some changes, you should see a reduction in cost etc.

As one of the changes is inside the HP unit I'm going to ask you to contact Grant themselves. You need to tell them that you suspect the HP flow pump is set to high and WC is not turned on. Also, if it was a Grant recommended installer, that you have been having problems with them to get it sorted (Spin a yarn etc).

The other point to discuss is @transparent notes about 3ph / single phase and how it may work.

A third thing to look at is insulation on the pipes, if they have done the same outside, these need fixing.

Another thing I would look at is checking all rads have been bleed, new systems / setup should be done more often till they settle down

If you get no joy from Grant let us know

Edit - just to check, the readings from the controller where taken when the HP was in CH mode and not doing DHW ?

Pipe insulation is inexpensive.
It's a very important part of your heat pump installation, and needs doing well.

Here's Class-O Nitrile-rubber pipe insulation from BES.

They offer Kaiflex. Armacell is similar.

You need a wall thickness of at least 13mm.
Use 19mm if space permits.

Lap over any gaps using the 3mm thick tape.

They offer large-diameter lengths of 42mm and 54mm which should work OK for valves.

Join splits and ends together using a standard contact adhesive.

For external pipe insulation, use the products with UV resistance, usually sold for solar thermal arrays.
Ensure that no rain can enter between the insulation and the pipe.
Seal the ends with a smear of waterproof acrylic mastic such as CT1, which you can apply to wet surfaces.

Post a photo here of where the pipework enters the house from the external unit.

This should be insulated right the way through the wall, and have an impact-resisting sleeve around that.

Brilliant. I have Grant coming to perform a service next month so will address those things then.

My electrician told me that although we have 3 phase, the HP is running on just one of the phases.

Most of the pipework is insulated, the worst is on that photo. All of the exterior is well insulated.

Rads are all bled and seem to have even heat.

I'll update as soon as i see the Grant engineer.

Many thanks for your time today, it's much appreciated.