Posted by: @derek-m

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Who is the manufacturer?

Mitsubishi

I observe that under Mitsubishi auto adaption that set back to 15C at night causes the HP to cease heating and runs in freeze stat until the next set point at 0600. When it was seriously cold recently, in the minus 10C area over night, it was waking up around 0500 hours to commence its days work regardless that the wireless room stat was not calling for heat.

Unfortunately MCS does not always mean a good installation.

Posted by: @abernyte

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Posted by: @derek-m

↑

Who is the manufacturer?

Mitsubishi

I observe that under Mitsubishi auto adaption that set back to 15C at night causes the HP to cease heating and runs in freeze stat until the next set point at 0600. When it was seriously cold recently, in the minus 10C area over night, it was waking up around 0500 hours to commence its days work regardless that the wireless room stat was not calling for heat.

It would appear that auto adaptation was actually 'adapting' to the adverse weather condition. 😎 Well done Mitsubishi. 😀 

Would you care to name your installer?

I would readily but the guy is seriously ill at present, hence the manufacturer service contract.

In reality, without monitoring equipment installed, it is very difficult to determine the actual, accurate performance of any heating system regardless of technology. Here is a link to a Linked in post, of a heating consultant finding out that his gas boiler is only 67% efficient after putting monitoring equipment on.

https://www.linkedin.com/feed/update/urn:li:activity:7019635213781585920?updateEntityUrn=urn%3Ali%3Afs_feedUpdate%3A%28V2%2Curn%3Ali%3Aactivity%3A7019635213781585920%29

As a rule of thumb, if the heat pump system has a buffer tank, system separation, if you can see more than 1 pump, and there are third party thermostats, there is little chance that there will be any level of reasonable performance and there is a good possibility that the bills will be very high.

@editor they can but if you go ahead and purchase based on the information supplied then it must be accurate and honest otherwise you probably have a claim

@sapper117, I guess it comes down to people and their ‘experience’. We purchased our property from people that were used to buying and selling properties that they fixed up and sold, and they were less than truthful in their signed documents and forms.

When we raised this with our solicitor post purchase (having discovered the issues after moving in), the legal fees and claims process was very costly and not worth the financial effort.

I suspect it might be the same with a bodged heat pump. If you have the capital, it might be cheaper to fix and replace then to seek legal routes to get financial compensation. 

@editor I suspect you are right in England - up north we have to sign docs with legal answers and each sale has a week to check elec gas boilers etc which if the buyer is well briefed and carried out their due diligence then they will have an engineer in on day one. As a retired property manager I would organise this for clients buying a new property ( new to them) and never had a problem here.

If I were buying a place with tech I wasn't familiar with, I'd probably look for an expert to do an inspection.  Surveyors are common for structural issues, electricians for electrical checks, boiler people for gas heating and I don't think heatpumps are much different. So I might pay somebody to visit and inspect - if I didn't know anyone, likely finding somebody who is certified by the manufacturer of this particular model to check it's installed correctly.

In this instance I probably wouldn't trust a 'gas safety certificate' or its heatpump equivalent (proof that it's been serviced recently) since we don't know if the person who recently serviced it knew what they were doing, unlike gas safety certs which are well understood.  Evidence of servicing is good, like GasSafe or HETAS paperwork is - although heatpumps don't really need a lot of servicing so it wouldn't be a showstopper if it didn't exist.

If I were being picky I might also ask my inspector to do heatloss calcs and confirm the unit is correctly sized.  It might be too large if additional insulation was added after it was installed.

Although I might be tempted to make sure there's some slack in the budget just in case it did need to be replaced - which should be cheaper than a full install since it's mainly the outdoor unit that would be changed.

@prunus the odds are the heat pump unit would be ok its the installation and heat calcs you would need checked as it seems that most of the problems emulate from failing here - and costs to make good could be larger than a new pump