@derek-m I will give you all the model numbers tomorrow, when I get a moment. We're based just out of Thirsk, & I will definitely give you as much info as possible to enable us to optimise the curve for my specific house. We have already been advised by a friend who got Solar & Heat Pumps a few months ago to look at the myenergi eddi diverters, so they are definitely also on my todo list

@justinsb No problem, just send the data at your convenience.

@justinsb 

One thing that I forgot to mention, if you find that your home is too hot or too cold you can move the upper and lower points of the weather compensation curve from the main controller screen.

After setting weather compensation the screen should be showing a large '0' (zero). If your indoor temperature has settled at 19C, but you require 21C, then use the '+' key to change the 0 to +2, obviously if your home is too warm then lower the setting.

When the curve is correctly adjusted then you should be able to revert the setting to 0.

@derek-m I'll let the system settle for a couple of days & see how it pans out - & if it needs tweaking. My screen is now showing the big Zero, as expected, which is always promising. Once we have done all of this, we should have enough to be able to cook up a How To guide that we can upload here & point anyone else to who needs to do the same thing.

@derek-m here's our current kit list. I'll add the Solar stuff when it all gets installed.

PUZ-HWM140VHA 14kW – R32 Mitsubishi Zubadan Model
PAC-IF073B-E Mitsubishi 300l cylinder

Honeywell T3R remote thermostat sat out in a relatively sensible place on the landing

We've got 4 bedrooms, 2 additional offices, dining room, sitting room (K3), a bathroom, en-suite & a sun room (K3)
Stelrad K2's everywhere, with a couple of K3's in the bigger rooms.
Basic TRV's on almost all the radiators. All left on max except for a couple of bedrooms, which have been set a bit lower.

@justinsb 

Justin,

Where is the controller (where you made the changes to the weather compensation) located.

Thermostats and ASHP's don't work together particularly well, for reasons I have explain in numerous other posts on the forum. Also TRV's can limit the flow of water around the system, which can have an effect on system performance.

Don't panic. As the weather compensation lowers the water flow temperature the TRV's will open up to allow more flow through the radiators. Leave the thermostat at its present setting overnight and then during the day raise the setting by 1C. When the weather compensation is fully in control, the indoor temperature should not increase if you raise the thermostat setting. If the temperature does increase then the weather compensation requires further optimisation.

Do you know the heat loss and floor area of your home?

Naturally, they put the controller in the hot cupboard! I'll find the floor area & heat loss calcs in the morning (hopefully). I will raise the temp by 1C tomorrow & report back

@justinsb 

That's a shame, but not to worry. If you look at section 7 'Main remote controller operation' of the controller manual, you will see mentioned 'Energy monitor'.

I have not been physically intimate with a Mitsubishi controller, so I am not 100% certain about the button pressing sequence, but it would appear that if you press F4 and then F4 again, from the main screen, it should display 'Consumed electrical energy' and 'Delivered energy'. Delivered energy divided by Consumed electrical energy provides the Coefficient of Performance (COP), not to be confused with COP26. This is a measure of how efficiently the ASHP is performing. You may wish to record these values for posterity.

@justinsb exactly where mine is - directly above the solar inverter which gets very very warm. I'm kicking myself for not getting them to punch it through the wall into the main living room. I fear its a job I might need to do, however I dont know how far it will run and dont want it randomly in the middle of the wall.

Posted by: @batalto

@justinsb exactly where mine is - directly above the solar inverter which gets very very warm. I'm kicking myself for not getting them to punch it through the wall into the main living room. I fear its a job I might need to do, however I dont know how far it will run and dont want it randomly in the middle of the wall.

Another team of 'experts' who pretend to know what they are doing.

@derek-m to be fair they did ask me where I wanted it. As I was using a thermostat I just said put it there (and pointed to the place). I think I do have enough to move it. So I could fairly easily pop it through the wall myself. Just need to get the bosses approval and then I'd need to work out how to "de zone" the house (as we have upstairs and downstairs).

@batalto, we also asked for ours to remain in the utility room cupboard (where it’s always roasting) to replace the old controller. What irks me though is that instead of taking the easy option, the installers should should have advised us to place the controller outside the cupboard, or quite easily on the other side of the way in the main living area which would have given us more options going forward. They’re all small things that have an impact on the efficiency of the system.