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ASHPs - makes and servicing requirements


newhome

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I’m going round the loop again looking at whether I should swap my electric boiler for an ASHP

 

I haven’t got any quotes as yet but one of the installers offers LG and Viessmann ASHPs. I haven’t heard of Viessmann before. Any opinions on them or the latest LG ones? 
 

The subject of annual servicing came up. I don’t have any annual servicing of my current system at present. The TS doesn’t need servicing and all I do with the boiler is empty the magnaclean occasionally. With an MCS installed ASHP an annual service is required to avoid voiding the warranty, and apparently one is needed for the RHI scheme too. The first installer I spoke to charges £150 plus VAT but other people seem to be paying up to £400. I’m ok with up to £200 a year but paying £400 seems crazy and makes me start to question the cost benefit of an ASHP

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You can't (or at least will de disappointed if you do) keep the thermal store so you should factor in replacing that with an UVC.  An UVC needs an annual service, more of a check that all the safety features are working rather than a service in the sense you would think of with say an oil boiler.  It just requires a plumber with the right ticket and takes no more than 2 hours.  So your challenge will be finding someone that does that at a fair rate.  I would regard £150 as the absolute max for that personally let alone any more.

 

An ASHP does not in theory need a service other than perhaps check the air intakes are not blocked with leaves etc.  I would love to be a fly on the wall and see what someone does when they come to "service" it.

 

I have an LG ASHP and you have probably read about the "issues" I had with it and the little help I got from the supplier, I really had to figure it out all for myself and devise work arounds as the root problem is still there.  But mine is an old model, so I would not like to say if you are likely to experience problems or not with their current offerings.

 

How long is the warranty of an ASHP with this annual service?  You surely only need to pay that until the warranty has expired then just get the UVC serviced after that.

 

 

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11 minutes ago, Declan52 said:

Why would you need to change from a thermal store to a uvc. If it works now using an electric boiler why would it not work with an ashp. Your only changing the method you use to heat the water. 

An ASHP will not heat DHW much above 50 degrees.

 

If you heat a UVC to 50 degrees, you can then draw hot water from it and you get 50 degree hot water up to the point the tank runs out.

 

If you heat a thermal store to 50 degrees, you will get 50 degree water out to start with.  But because you are not actually drawing the water off, you are merely extracting energy from it, by the time you have drawn say half the tank capacity from it, the water will be coming out a lot colder.

 

So it is generally accepted you need to store the water in a thernmal store a lot hotter than your desired water temperature.

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I was hoping to keep the TS but know that it might not be possible. That adds to the cost of course and ROI calculation. 
 

I’ve been reading on a heat pump group that apparently the service is about 2 hours and someone posted the link to the Ecodan servicing:

 

https://les.mitsubishielectric.co.uk/homeowners/heating-service-and-maintenance?fbclid=IwAR224i4dvlnDHoc7l9utg41kbknCgPKPrH5lx1JH2E8emVaNqF2lcusaBnA

 

On a different subject can you get the heat pump to just run at the times when the electricity rate is low if you are on a variable tariff? I’m on a flat rate at present but wanted to move to an agile tariff in the future. 
 

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I heat mine to 64 for my thermal store and it keeps long enough for my needs. If I would change to an ashp I understand that I would either have to adjust my use to suit that lower temperature. The only time you would notice it would be using the shower or bath but for ufh it would still be fine. For the cost of replacing the tank you could programme the immersion to come on to boost the temp higher to overcome this issue. Plus with excess pv I would only be paying for this boost 5 months of the year.

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15 minutes ago, Declan52 said:

For the cost of replacing the tank you could programme the immersion to come on to boost the temp higher to overcome this issue.


I think if claiming RHI you’re not allowed to do too much in the way of topping up the heating. As you say it’s not the UFH that will be an issue, it’s hot water for showers / baths. 

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3 minutes ago, newhome said:


I think if claiming RHI you’re not allowed to do too much in the way of topping up the heating. As you say it’s not the UFH that will be an issue, it’s hot water for showers / baths. 

Just don't tell anyone.  This message will self destruct in 5, 4, 3.......................

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7 minutes ago, newhome said:


I think if claiming RHI you’re not allowed to do too much in the way of topping up the heating. As you say it’s not the UFH that will be an issue, it’s hot water for showers / baths. 

Your allowed to use the immersion to top it up. How could they stop you. 

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57 minutes ago, newhome said:


I think if claiming RHI you’re not allowed to do too much in the way of topping up the heating. As you say it’s not the UFH that will be an issue, it’s hot water for showers / baths. 

You can claim RHI on an ASHP  for the space heating only. You don't have to use the ASHP for DHW at all to claim RHI

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31 minutes ago, newhome said:


How would you get hot water for DHW then? 

You can heat the DHW however you like, including from the ASHP. The point is RHI is for the space heating. If you have additional sources of space heating this will reduce the RHI, but the mix of sources you use for DHW is irrelevant to the claim. (AIUI. Making my claim in 2 months)

 

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