Bad ASHP Install on New Build - Legal Stand Point?

ComicGeek

Also thinking that the last Samsung project I did earlier this year, we had to include 50/60 litre buffer tanks within the hot water cylinder to meet their minimum water volume requirements. So things I would be checking would be:

Siting of external condenser - sufficient air flow, length of exposed pipework before it enters house.
Flow temp setting on heat pump.
Flow temp setting at UFH.
Flow temp setting for hot water generation - what is the pasteurisation cycle set at for the hot water? Should heat up once a week to 60 degrees, but lower temp the rest of the time.
Total water volume for the system - check if additional buffer tank has been included.
Backup heater - check if electric heater is installed any where on the system.

I would put money on the builders using their normal plumber for the project, and who has never installed a heat pump before. It could just be a simple error somewhere, don't spend any money until you can work out what the actual issue is.

Have you spoken with Samsung technical team, and asked them for advice? 
Are the installers registered under their EHS training scheme? Do you have the extended 7 year warranty for the unit?

Reed_Richards

You have my sincerest sympathies.  You thought you were buying a good energy-efficient house and it turned out to be anything but.  That said, heat pumps are highly eco-friendly but they won't save you a huge amount in heating bills compared to oil or gas because both these fuels are so much cheaper per kWh than electricity is.  For low bills you need both very good insulation and your heat pump working properly.  The other issue is that this is not the right section of the forum to post about what is essentially a legal issue.  You'll get plenty of suggestions here about how to make your heat pump work better but it was really the job of the house builders to make sure that was done properly in the first place.  

shinytop

I have a 14kW ASHP in a slightly smaller, well insulated but older bungalow. I think my real max heat loss is 8-9 kW.  As @ComicGeek says, your real heat loss is going to be more than 3-5 kW.  My SCOP isn't particularly good by modern standards but it's still well over 3 (measured by proper meters).   

Are you sure your COP is around 1?  The internal measurements on some ASHPs are very inaccurate. Even when it's freezing cold outside and the ASHP is defrosting 3 x per hour my COP is rarely less than 2. 

What is your electricity consumption in, say Feb or Nov 24 and how warm is your house?  Happy to share some numbers to compare.

 

farmerjj

shinytop said:

I have a 14kW ASHP in a slightly smaller, well insulated but older bungalow. I think my real max heat loss is 8-9 kW.  As @ComicGeek says, your real heat loss is going to be more than 3-5 kW.  My SCOP isn't particularly good by modern standards but it's still well over 3 (measured by proper meters).   

Are you sure your COP is around 1?  The internal measurements on some ASHPs are very inaccurate. Even when it's freezing cold outside and the ASHP is defrosting 3 x per hour my COP is rarely less than 2. 

What is your electricity consumption in, say Feb or Nov 24 and how warm is your house?  Happy to share some numbers to compare.

 

Thanks,

Here are pictures from the screen and also our electric meter (turned on end of June):

Reed_Richards

Oh dear, I see waht you mean about COP near 1!

ComicGeek

It shouldn't be possible for the ASHP to even get to COP near 1, regardless of conditions. The fuse rating of the heat pump would be too low, even at 65 degrees flow temp. 

I had another look at the Samsung unit, and the indoor unit MIM-E03CN can be installed with a 3 kW booster heater AND a 3 kW backup heater in series. The hot water cylinder immersion heater (used for legionnella protection once a week) is also controlled through the ASHP system. More likely that these supplementary heaters are running in the background and causing the high readings and bills. 

shinytop

Interesting.  My house is quite similar to yours and my ASHP consumed 688 kWh and delivered 2268 kWh in November.  Yours delivered just over 800 kWh.  Unless your house is extremely well insulated and your HW usage is low that seems too little. How warm is your house?  I agree with @ComicGeek that your ASHP COP can't be that low.  So it could either be using direct heat or the measurements are wrong - or a bit of both. 

Have you compared notes with any of your neighbours who have a similar set up?

farmerjj

shinytop said:

Interesting.  My house is quite similar to yours and my ASHP consumed 688 kWh and delivered 2268 kWh in November.  Yours delivered just over 800 kWh.  Unless your house is extremely well insulated and your HW usage is low that seems too little. How warm is your house?  I agree with @ComicGeek that your ASHP COP can't be that low.  So it could either be using direct heat or the measurements are wrong - or a bit of both. 

Have you compared notes with any of your neighbours who have a similar set up?

We try and keep the house at 19 degrees C.

The emersion heater is turned off on the DHW tank (and has been checked that it's not wired incorrectly.

We have a disinfectant cycle that runs once a week but we don't see usage on that day go even more through the roof.

Neighbours have smaller Samsung ASPH (even though our houses are near enough the same SQ FT, just theirs is on three levels, ours is a bungalow).

We have another ASHP expert coming round on Tuesday so at least I have 3 reports done to show the issues with the system.

It's costing us a fortune and we need it fixed one way or another.

farmerjj

ComicGeek said:

It shouldn't be possible for the ASHP to even get to COP near 1, regardless of conditions. The fuse rating of the heat pump would be too low, even at 65 degrees flow temp. 

I had another look at the Samsung unit, and the indoor unit MIM-E03CN can be installed with a 3 kW booster heater AND a 3 kW backup heater in series. The hot water cylinder immersion heater (used for legionnella protection once a week) is also controlled through the ASHP system. More likely that these supplementary heaters are running in the background and causing the high readings and bills. 

Booster heater function is: ON
Delay time: 60min

Overshoot: 0 degrees.

Water Law (weather comp)

Low: 15 High: -2.0
Low target: 25 High Target: 40

DHW Application:

Use (hysteresis Termo ON/OFF State).

Disinfection: ON Sunday 11pm.

Target Temp: 60

Duration: 60mins

Not sure if that means more to you than it does me?!

Magnitio

Have you any updates on this? Did you insulate all the pipework? This is quite easy to do, and given the description of how poorly it has been done and the impact of it getting wet, could make a reasonable difference.