@derek-m Ah ok, yes my intention is to do as you describe. But I did think that feedback of the space temp to the controller would help it adjust flow temp but as you say get the compensation right and it shouldnt need it.

Ours using Grahams settings is keeping the temp in less than a 1 degree range going off/on throughout the day, but if we can save some electric with compensation then I'm all for it, especially now I know what our tariff is going up to in April. 

@grahamh Hi Graham, I have one question for you. Our Midea ASHP is set the DHW as a priority and should kick in anytime the temp drops 10 degrees below the set point (50), however sometimes this doesnt happen and I have seen it down to 29 degrees and still not kicking in. So I have either manually set it on or set a timer. Have you seen this with any other customers units?

Also do Midea release any firmware updates? 

Posted by: @mookyfoo

@derek-m Ah ok, yes my intention is to do as you describe. But I did think that feedback of the space temp to the controller would help it adjust flow temp but as you say get the compensation right and it shouldnt need it.

Ours using Grahams settings is keeping the temp in less than a 1 degree range going off/on throughout the day, but if we can save some electric with compensation then I'm all for it, especially now I know what our tariff is going up to in April. 

From an efficiency point of view the important thing is to get the weather compensation correct. A further refinement now incorporated in many heat pump controllers is 'auto adaptation' or 'modulation' control, which fine tunes the weather compensation to control the indoor air temperature more accurately, but to do so requires the controller to be correctly located, or a remote sensor to be installed.

@mookyfoo yes its really common, there are internal timers which limit how often the unit can go into hot water mode, usually set to about 90 mins. so if you finish a hot water cycle then have a bath the unit cant heat the water for another 90 mins. these are all adjustable in the settings. i prefer to time clock the cylinder so it only heats in cheap electricty periods but the installers leave it on 24 7 as its easier and you get les call backs. re firmware, no this is not something that any manufacturer does.

@grahamh It could be at 29 degrees for 6-7 hours and still not kick in, if it was only 90mins which I think its set to it wouldnt be an issue. Even a timer didnt work over night, in fact I think we have gone 2 before and then had to manually turn it on. Its been at 30 most of today so again I'm going to start it manually again.

Almost feel it needs a reset or something.

sounds like a setting or a timer has been set up, i would drag the installer back and ask them to make sure its set up right, i cant remember how to set timers on midea,  give freedom heat pumps a call and ask them how to do it and check the unit im sure they will help. 

@grahamh I am running the same test as Graham did. Let's see what happens with a new build, fixing the flow temp. So my house has UFH downstairs, rads upstairs. My previous weather comp. settings were 25c@+15 and 40@-10. Now fix flow @35c. I will put the results here after I run it like this for a while.

Posted by: @derek-m

I read your article with interest, and I am not surprised that you only achieved an energy reduction of 8% using weather compensation with water flow temperatures ranging from 37C to 55C.

I'm not sure because I didn't leave my unit off compensation long enough to find out, but even if it was only 8%, find me someone who pays the bills who would reject saving 8%!

I don't think it will be saved from the system development costs because there's little chance of it being removed from controllers already developed and they will have flow temperature control and indoor thermometers anyway, so a thermometer on the outdoor unit and programming to calculate target flow temperature from it is probably not much more. Maybe it would be saved from the installation cost but would enough be saved to pay for the whole lifetime and would that saving really be passed on to the customer anyway?

Posted by: @grahamh

re firmware, no this is not something that any manufacturer does.

Mitsubishi definitely release firmware updates. The November 2021 one did not go smoothly for some.

Posted by: @mjr

Posted by: @derek-m

I read your article with interest, and I am not surprised that you only achieved an energy reduction of 8% using weather compensation with water flow temperatures ranging from 37C to 55C.

I'm not sure because I didn't leave my unit off compensation long enough to find out, but even if it was only 8%, find me someone who pays the bills who would reject saving 8%!

I don't think it will be saved from the system development costs because there's little chance of it being removed from controllers already developed and they will have flow temperature control and indoor thermometers anyway, so a thermometer on the outdoor unit and programming to calculate target flow temperature from it is probably not much more. Maybe it would be saved from the installation cost but would enough be saved to pay for the whole lifetime and would that saving really be passed on to the customer anyway?

Posted by: @grahamh

re firmware, no this is not something that any manufacturer does.

Mitsubishi definitely release firmware updates. The November 2021 one did not go smoothly for some.

Hi mjr,

The point that I was making was that even if a system is set to weather compensation, it is equally important that it is correctly configured, which would produce a reduction in energy consumption in the order of 20%, rather than the achieved 8%.

Posted by: @derek-m

The point that I was making was that even if a system is set to weather compensation, it is equally important that it is correctly configured, which would produce a reduction in energy consumption in the order of 20%, rather than the achieved 8%.

Yes, understood, and my point was that even 8% would be worth saving these days. 20% definitely is.

@grahamh has another post which mentions why he used 37°c minimum: "people moaning the rads are cold"

But I'd prefer that and explaining the physics until they understand (or their eyes glaze over and they stop moaning to me 😉 ) to people moaning the heat pump spent all the money and having to explain I had an inefficient heating setup because I thought they were too stupid to understand...

if you want to make your midea really sing and dont mind weather comp contact evergreen energy or freedom heat pumps and ask to buy a homely. homely is a super intelligent learning thermostat which actually drills into the units and takes over the control. if you are on agile tarrifs it also controls to the tarrif as well. its amazing IF you dont mind the radiator temperature fluctuating, its about £100.

unlike all other stats because homely is driving the weather comp set temperature they can achieve some pretty impressive cops, ive seen data showing over 4s on radiators.

tell them i sent you 

Posted by: @grahamh

if you want to make your midea really sing and dont mind weather comp contact evergreen energy or freedom heat pumps and ask to buy a homely. homely is a super intelligent learning thermostat which actually drills into the units and takes over the control. if you are on agile tarrifs it also controls to the tarrif as well. its amazing IF you dont mind the radiator temperature fluctuating, its about £100.

unlike all other stats because homely is driving the weather comp set temperature they can achieve some pretty impressive cops, ive seen data showing over 4s on radiators.

 

tell them i sent you 

Hi Graham,

Which agile tariffs would you recommend?