Whilst Regs allow o...
 
Notifications
Clear all

Whilst Regs allow on-off simple thermostats (Nest, Hive, Heatmiser, Honeywell, etc) Installers should never be responsible for failing heat pumps!

23 Posts
7 Users
27 Likes
3,414 Views
(@alec-morrow)
Honorable Member Contributor
1306 kWhs
Joined: 2 years ago
Posts: 209
Topic starter  

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..

 

 

Professional installer


   
Quote
(@alec-morrow)
Honorable Member Contributor
1306 kWhs
Joined: 2 years ago
Posts: 209
Topic starter  

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.

 

 

 

Professional installer


   
ReplyQuote
Morgan
(@morgan)
Noble Member Member
3799 kWhs
Joined: 3 years ago
Posts: 521
 

@alec-morrow 

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.


   
Mars, Alec Morrow, Mars and 1 people reacted
ReplyQuote



(@derek-m)
Illustrious Member Moderator
13236 kWhs
Veteran Expert
Joined: 3 years ago
Posts: 4093
 
Posted by: @morgan

@alec-morrow 

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.


   
Morgan and Morgan reacted
ReplyQuote
Morgan
(@morgan)
Noble Member Member
3799 kWhs
Joined: 3 years ago
Posts: 521
 

@derek-m 

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.


   
ReplyQuote
(@kev-m)
Famed Member Moderator
5550 kWhs
Joined: 3 years ago
Posts: 1299
 
Posted by: @alec-morrow

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.  


   
witchcraft, Saz, heat-pump-newbie and 3 people reacted
ReplyQuote
(@peterr)
Estimable Member Member
551 kWhs
Joined: 2 years ago
Posts: 67
 
Posted by: @kev-m

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!


   
witchcraft, Saz, Bernard_S and 7 people reacted
ReplyQuote
(@prunus)
Estimable Member Member
166 kWhs
Joined: 3 years ago
Posts: 56
 

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.

image

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...


   
ReplyQuote
(@alec-morrow)
Honorable Member Contributor
1306 kWhs
Joined: 2 years ago
Posts: 209
Topic starter  
Posted by: @prunus

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.

image

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 

Professional installer


   
ReplyQuote



(@alec-morrow)
Honorable Member Contributor
1306 kWhs
Joined: 2 years ago
Posts: 209
Topic starter  

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.

 

 

 

Professional installer


   
ronin92 reacted
ReplyQuote
(@ianjrw)
Eminent Member Member
127 kWhs
Joined: 2 years ago
Posts: 18
 

Hi, new here and looking to get ASHP installed asap.

What should i be asking potential re on-off thermostats? Seems that those we've spoke to are looking to install Honeywell or equivalent...

Thanks in advance for any insight.


   
ReplyQuote
(@alec-morrow)
Honorable Member Contributor
1306 kWhs
Joined: 2 years ago
Posts: 209
Topic starter  

@ianjrw just ask for the heat pumps own controller. That’s it.

 

 

Professional installer


   
ReplyQuote
Page 1 / 2



Share:

Join Us!

Latest Posts

x  Powerful Protection for WordPress, from Shield Security
This Site Is Protected By
Shield Security