It’s a class thing I guess..the worst aspect of the U.K, A heating engineer is always to blame for failures of what is world class technology, your heat pump!
Well, rumour has it, that a sales rep from a reputable global company has installed a heat pump with evohome and in his first year of operation only got a CoP of 2.4..with on-off controls
I know people are frustrated but the rot on the heating industry goes much deeper than the class bashed tradesman.
Regulations defined what you get offered, not good engineering.
keep it simple people one controller from your heat pump manufacturer, or their zonal control kit..
For those who don’t get it at the heart of the issue is a dichotomy in policy. Heat pumps, because they are kw restricted, have to deliver a stable state heating system, ie be available to deliver heat to stop things getting too cold. This is fine because houses have regular usage patterns.
U.K. policy works on the assumption that a heat generator is best off as it consumes no energy. An oversized boiler recovered the heat quickly because boiler fuel is energy intense.
On off controls shut down the heat generator.
Compensation controls wind up and down the heat generator changing flow temperature to satisfy demanded room temperature
Compensation controls deliver savings on gas boilers too, about 10-15% higher the warmer outside!
Weather compensation has been mandatory in Germany since 1985, and since 2001 in Holland Compensation controls have been mandatory, as far as I know Compensation control of heating appliances are used in Switzerland, Denmark, Scandinavian countries, and North Italy.
Your hapless installer has paid his dues for training and gets guided by policy and manufacturers. He too expects things to work. But between what the consumer wants (Nest,Hive, Heatmiser) and what is correct he defers to the customers..as you would too!
So installers are never to blame. Suited and salaried civil servants are who allow on-off controls on heat pumps are the baddies here.
Good morning Alec. My Ecodan system installed not long before xmas 2021 has Heatmiser on/off control. I have the stat set permanently at 24C and the control set at weather curve. The house is a lovely even 21/22C 24/7. The installer was apparently unable to source the Mitsubishi wifi receiver and room controller. I have now after some time sourced and am in possession of those two items. Awaiting the installer returning to swap them over for me. Once done I hope to have 'proper' weather compensation control.
Retrofitted 11.2kw Mitsubishi Ecodan to new radiators commissioned November 2021.
14 x 500w Monocrystalline solar panels.
Good morning Alec. My Ecodan system installed not long before xmas 2021 has Heatmiser on/off control. I have the stat set permanently at 24C and the control set at weather curve. The house is a lovely even 21/22C 24/7. The installer was apparently unable to source the Mitsubishi wifi receiver and room controller. I have now after some time sourced and am in possession of those two items. Awaiting the installer returning to swap them over for me. Once done I hope to have 'proper' weather compensation control.
Hi Morgan,
You actually already have weather compensation control, by installing the additional equipment you will actually achieve auto adaptation control.
Indeed. But I will soon have ‘proper’ & full control with Mitsubishi components as opposed to third party. I won’t have to to set an artificially high temperature to achieve the aim.
Retrofitted 11.2kw Mitsubishi Ecodan to new radiators commissioned November 2021.
14 x 500w Monocrystalline solar panels.
For those who don’t get it at the heart of the issue is a dichotomy in policy. Heat pumps, because they are kw restricted, have to deliver a stable state heating system, ie be available to deliver heat to stop things getting too cold. This is fine because houses have regular usage patterns.
U.K. policy works on the assumption that a heat generator is best off as it consumes no energy. An oversized boiler recovered the heat quickly because boiler fuel is energy intense.
On off controls shut down the heat generator.
Compensation controls wind up and down the heat generator changing flow temperature to satisfy demanded room temperature
Compensation controls deliver savings on gas boilers too, about 10-15% higher the warmer outside!
Weather compensation has been mandatory in Germany since 1985, and since 2001 in Holland Compensation controls have been mandatory, as far as I know Compensation control of heating appliances are used in Switzerland, Denmark, Scandinavian countries, and North Italy.
Your hapless installer has paid his dues for training and gets guided by policy and manufacturers. He too expects things to work. But between what the consumer wants (Nest,Hive, Heatmiser) and what is correct he defers to the customers..as you would too!
So installers are never to blame. Suited and salaried civil servants are who allow on-off controls on heat pumps are the baddies here.
I'm not so sure. Anyone installing heat pumps should know how they work. If they do, they will know an ASHP running at 50C with 3rd party thermostats is not the most efficient set up. If they don't know this then they shouldn't be installing heat pumps. But they also know that this set up will work and will be familiar to customers and that they (the supplier) won't be paying the electricity bills. Setting up weather compensation takes time and is likely to need more after sales service, which costs the supplier time and money.
I agree about the lack of regulation and training but installers, some of whom are national companies, need to take some responsibility.
I'm not so sure. Anyone installing heat pumps should know how they work. If they do, they will know an ASHP running at 50C with 3rd party thermostats is not the most efficient set up. If they don't know this then they shouldn't be installing heat pumps. But they also know that this set up will work and will be familiar to customers and that they (the supplier) won't be paying the electricity bills. Setting up weather compensation takes time and is likely to need more after sales service, which costs the supplier time and money.
I agree about the lack of regulation and training but installers, some of whom are national companies, need to take some responsibility.
Agree with this 100%. One of the major selling points of ASHP is their "environmental friendliness", so installers should be required to leave any system they install running in the greenest, most efficient way possible.
Our installer, who claim to be "The No 1 heat pump installer in the country" left our system running at a fixed flow of 50C controlled by thermostats. When I queried this and mentioned changing to weather compensation, their response was that they "would advise against using weather compensation as it can throttle back the delivery of heat from the pump considerably resulting in a lower than desirable flow temperature" - that is a direct quote from an email from them. Every bit of their "expert advice" tells me to use a fixed flow temp of 50C. I have, of course, ignored them!
It's completely nuts. This is the compressor speed of my Grant (aka Chofu) ASHP, using the Honeywell Lyric on/off controller the installer supplied. The Lyric is doing TPI, which attempts to learn the dynamics of the house and run the ASHP for a variable length in each time period to keep the house at a constant temperature. It's impossible to turn off TPI and, on the longest period, it's doing this every 20 minutes. As installed it was doing it every 10 minutes.
The frustrating thing is the Chofu has a perfectly good room controller integrated into it, but the Grant instructions deleted that part from the setup guide. That means my setup has the pumps and valves wired to the Honeywell, as per the Grant instructions.
When I get some time and a cold day I plan to see if I can enable the room controller and bypass the Honeywell...
It's completely nuts. This is the compressor speed of my Grant (aka Chofu) ASHP, using the Honeywell Lyric on/off controller the installer supplied. The Lyric is doing TPI, which attempts to learn the dynamics of the house and run the ASHP for a variable length in each time period to keep the house at a constant temperature. It's impossible to turn off TPI and, on the longest period, it's doing this every 20 minutes. As installed it was doing it every 10 minutes.
The frustrating thing is the Chofu has a perfectly good room controller integrated into it, but the Grant instructions deleted that part from the setup guide. That means my setup has the pumps and valves wired to the Honeywell, as per the Grant instructions.
When I get some time and a cold day I plan to see if I can enable the room controller and
The issue is that an ASHP and boiler is part of a system for which there is no training in the U.K. People buy ASHPs and boilers with out fully comprehending how components interact.
Thats why compensation controls need to be mandated. In the absence of that using the controllers supplied by the pumps is a smart move.
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