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Air source heat pump performance

 
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Air Source Heat Pumps (ASHPs)
Last Post by batalto 4 years ago
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 Sam
(@sam)
Trusted Member Member
Joined: 5 years ago
Posts: 24
29/03/2021 9:41 am  

Good morning all,

 

After months of problems and complaints, I finally have a formal report from LG categorically stating that our 9kw heat pump is undersized for our 2700 sqft home - which is why we cannot heat the rooms in weather with temperatures below 4° and why the pump is so horribly noisy in those conditions as it is under significant strain and working at full capacity 24/7 to try to do so.

This is fantastic progress, but what now? I'm about to approach the developer who built my new build property, but does anyone have any advice or knowledge of laws concerning sufficient heating systems? I need to make sure the builder and Omnie, who designed the underpowered system and have always maintained there's nothing wrong with it (although could never explain why my home wouldn't heat above 16.5° all winter) have no wriggle room and recognise their legal obligations.

Do I need to engage a solicitor? What should I do in the first instance?

Help!

Sam.

 



   
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 Kev M
(@kev-m)
Noble Member Member
Joined: 5 years ago
Posts: 1276
29/03/2021 10:40 am  

Sam,

do you know if RHI is being claimed by the developer (I assume it isn't by you)? If so they would have to have filled in an MCI calculation and submitted it to OFGEM. That should ensure the sizing is correct.  It'd be worth asking them for this or anything else they used to size the system.  

Kev



   
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 George
(@george)
Estimable Member Contributor
Joined: 5 years ago
Posts: 85
29/03/2021 12:09 pm  

Have LG confirmed what size ASHP is suitable?

 

Do you have access to the system data showing flow rates/temps etc? It would be interesting to see the flow temp when the ambient temp is sub 4 degrees to see when every zone is calling for heat what it is actually flowing at.

 

If I switch on every single zone/radiator on our system it will only flow at 37-40 max. Is your property all radiators or a mix of UFH and radiators?


Mitsubishi Ecodan 14kw ASHP + 500l Cylinder


   
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Mars
 Mars
(@editor)
Illustrious Member Admin
Joined: 5 years ago
Posts: 4550
Topic starter 29/03/2021 12:17 pm  

@kev-m, do you know if there's a way of searching the MCS database?


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 Derek M
(@derek-m)
Illustrious Member Member
Joined: 5 years ago
Posts: 4425
29/03/2021 12:49 pm  

Hi Sam,

As suggested previously, have you been in touch with trading standards or consumer protection? They would probably be able to point you in the correct direction.

You should also get in touch with MCS, their helpline number is 0333 103 8130.

Personally I would not go down the route of getting a solicitor just yet, keep that as a last resort.

Your local MP may also be of assistance, since the government want us all go 'green'.

Hope this helps.

Regards,

Derek.

 

 



   
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Mars
 Mars
(@editor)
Illustrious Member Admin
Joined: 5 years ago
Posts: 4550
Topic starter 29/03/2021 1:12 pm  

@derek-m, I completely agree with you. The first point of attack would be MCS, but the only thing I'm unsure of (which I think Sam informed me of) is that the installers weren't MCS accredited. If they're not, there's not much recourse there. Sam can correct me if I've remembered this incorrectly. A phone call should clarify this. Also, if they were MCS accredited, there'll be insurance in play which Sam can use to get the matter resolved. Our MCS certificate states that we're insured by HEIS, and they'll put right any problems.

Trading standards and consumer protection is also a good course of action to pursue as a next step.

The solicitors play is a last resort in most cases, because of the money involved, but negligence and incompetence shouldn't be that difficult to prove, given that LG have now issued a formal report stating the incorrect size heat pump was installed.


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 Kev M
(@kev-m)
Noble Member Member
Joined: 5 years ago
Posts: 1276
29/03/2021 1:22 pm  

A quick looks suggests the MCS data is available but you need to ask for a login

https://certificate.microgenerationcertification.org/



   
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 Sam
(@sam)
Trusted Member Member
Joined: 5 years ago
Posts: 24
29/03/2021 1:44 pm  

Hi,

Mars, unfortunately you are correct. We do not have an MCS certificate. I've been advised to contact the builder with the report quoting the 2015 consumer rights act.

 

I suppose my main concern is that Omnie will simply write a report stating it is big enough.

Sam



   
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 Sam
(@sam)
Trusted Member Member
Joined: 5 years ago
Posts: 24
29/03/2021 1:53 pm  

I don't know about the flow data, although the technician has attached a data report that will hopefully mean something to the right people.

It's all underfloor heating and he's recommended a UN3 CHASSIS 12-16KW 1Ph.

He has calculated a heat loss of 8.61kw based on 0.035kw/m2 , leaving only a heating capacity of .39kw 



   
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 Sam
(@sam)
Trusted Member Member
Joined: 5 years ago
Posts: 24
29/03/2021 1:56 pm  

@kev-m

Hi, no RHI isn't being claimed by the builder as there's no MCS certificate.

 



   
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Mars
 Mars
(@editor)
Illustrious Member Admin
Joined: 5 years ago
Posts: 4550
Topic starter 29/03/2021 1:58 pm  

@sam, I would demand the heat loss and emitter calculation from Omnie. If they say that the heat pump is the correct size, they must provide the evidence to back that up, and the only way to do that is to share the aforementioned calculations. 

I can't remember if you told me this, but have you called MCS and verified from them that there isn't a MCS certificate for your property?


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Mars
 Mars
(@editor)
Illustrious Member Admin
Joined: 5 years ago
Posts: 4550
Topic starter 29/03/2021 2:00 pm  
Posted by: @sam

I don't know about the flow data, although the technician has attached a data report that will hopefully mean something to the right people.

It's all underfloor heating and he's recommended a UN3 CHASSIS 12-16KW 1Ph.

He has calculated a heat loss of 8.61kw based on 0.035kw/m2 , leaving only a heating capacity of .39kw 

I missed this earlier comment. Is the calculation from the LG technician, not Omnie?


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