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15 year old Daikin ASHP System

 
Air Source Heat Pumps (ASHPs)
Last Post by BGF 4 weeks ago
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 BGF
(@bgf)
New Member Member
42 kWhs
Joined: 1 month ago
Posts: 3
Topic starter 20/10/2024 2:38 pm  

Back in 2003 we installed a Dimplex GSHP at our house in Cumbria. Which was a disaster. Firstly there was an igneous layer at 95m that blunted the bore hole drills. Secondly the tailings from the bore holes flooded the road beside the house and finally the Dimplex unit never truly worked. It was ultimately replaced with a Kensa.

So when we moved to restore an adjoining old farmhouse we would have needed 4 bore holes and as there were several properties downhill that would have been engulfed with tailings we switched to ASHP.

We had the ASHP system installed in Nov 2008 when we renovated the 250m2 stone build listed farmhouse. It has single glazed Georgian windows and >> 10 cm of insulation in the loft. The walls are all ca. 1m thick stone.

System comprised two 3 phase Daikin 16kw heap pumps running two indoor wall units and a 700l thermal store. This was for two zone underfloor heating downstairs and radiators in the rest of the house. There is also a back boiler on the log burner that adds several kw into the thermal store. There are two 200l DHW tanks in the loft.  One Heat pump is Heating and one combined heating and DHW.

Last year we fitted Tado controlled radiator valves and a Tado wall thermostat for the Under floor heating in lounge.

After 15 years of paying Daikin to look after them under Maintenance contract the Maintenance expired last Friday and they will not renew it. On Saturday we noticed that the DHW heap pump was not functioning. The local engineer has tried a £600 replacement communication board without success.

I am reluctant to spend several k on a 15 year old heat pump. In the past we have had all the boards in the other unit replaced under warranty and it was several k. 

NB one of the pumps sprung a leak in the coil in Y1, The boards in Y5, flow sensors in Y8 and diaphragms in both in Y10 etc.

I spent yesterday making house measurements and using the NRG online heat loss calc and it says house has heat loss of 27,489 W and total heat loss of 135 W/m2. ( The original calculations in 2008 had assumed an extension that was never built).

I have been looking at the current long list of suppliers ( There are over 20 now cf 2008). My selection will be based on quality, price and length of warranty. 

Daikin had us pay 350 per year per unit for maintenance - so a single unit would be slightly preferable for a low warranty system

However, there are few domestic systems above 16 kw.

Master Therm have a 22 kw but calcs suggest it is not enough.

There are several small factory units or we use two units.

Also if we use a mono bloc we may have to dig up 2m of patio to lay new pipes into the house from heat pump.

We did not get a grant for the 2008 installation but as we are not replacing fossil fuel we don't plan to apply for a  current grant.

As building is listed and we replaced roof 12 years ago we cannot install solar - also ,buckle big hill between us and the sun.

Current heating DHW with the immersion heater so will have to do something soon...

I have asked MasterThem for a quote and was considering asking Aira.

Any other recommendations or suggestions ? 

 

 


   
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 Judith
(@judith)
Reputable Member Member
1731 kWhs
Joined: 1 year ago
Posts: 187
22/10/2024 8:08 am  

I have no connection with them whatsoever but why not ask Brendon at https://heacol.co.uk for advice & replacement? You’re in Cumbria and he’s well respected in the industry.

I’m glad to read your system has run for 15years since that was the age of our gas boiler when we replaced it. On going parts replaced in life us normal.

2kW + Growatt & 4kW +Sunnyboy PV on south-facing roof 9.5kWh Givenergy battery with AC3. MVHR. Vaillant 7kW ASHP (new & still learning it)


   
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 BGF
(@bgf)
New Member Member
42 kWhs
Joined: 1 month ago
Posts: 3
Topic starter 23/10/2024 9:12 am  

Thank you Judith. I have contacted them.


   
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Mars
 Mars
(@editor)
Illustrious Member Admin
22695 kWhs
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23/10/2024 10:24 am  

@bgf @heacol is an active member on our forums too.

Buy Bodge Buster – Homeowner Air Source Heat Pump Installation Guide: https://amzn.to/3NVndlU
From Zero to Heat Pump Hero: https://amzn.to/4bWkPFb

Subscribe and follow our Homeowners’ Q&A heat pump podcast


   
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 Brendon Uys
(@heacol)
Noble Member Contributor
2227 kWhs
Expert
Joined: 3 years ago
Posts: 358
23/10/2024 4:18 pm  

Thank you @editor and @judith \we have made contact.

Technical Director Ultimate Renewables Director at Heacol & Head of Domestic Heat Pump Design Net Zero British Gas


   
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Mars
 Mars
(@editor)
Illustrious Member Admin
22695 kWhs
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Joined: 4 years ago
Posts: 2722
24/10/2024 8:54 am  

Posted by: @bgf
↑

Thank you Judith. I have contacted them.

You’re in safe hands with @heacol.

 

Buy Bodge Buster – Homeowner Air Source Heat Pump Installation Guide: https://amzn.to/3NVndlU
From Zero to Heat Pump Hero: https://amzn.to/4bWkPFb

Subscribe and follow our Homeowners’ Q&A heat pump podcast


   
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 BGF
(@bgf)
New Member Member
42 kWhs
Joined: 1 month ago
Posts: 3
Topic starter 06/11/2024 2:55 pm  

Thank you to all who made suggestion.

An update - we are heating with one working 16kW heat pump and DHW from an immersion heater.

 

Heat Loss

I had initially used the NRG calculator and it suggested 27kW heat loss.

I downloaded and used the Freedom calc from this forum and it was 20 kW

I paid for an external heat loss calculation at its was just under 20 kW.

Brendon at Heacol ran calculations and it was  just under 20kW

Aira said it was 20 kW but was just based on a total floor area.

Mastertherm said it was 16 kW

N.B. we are in Cumbria and at 150m elevation.

 

We had Aira visit. 

They put the house floor area into their tablet and said we needed a 20 kW system. 

Aira heat pumps do not work in cascade and max single unit is 12 kW.

They could only offer  2 x 10kW Vaillant Heat pumps.

They then offered to replace all 14 radiators in the house with ones that they specify so that they could offer a 5 year comfort warranty.  The  inclusive price was 27k. Hence I was paying for  two heat pumps and for replacing all the radiators so that they could offer a 5 year comfort warranty.

The Vaillant warranty was 2 years but they would extend to 5. They initially did not think that they could make the back boiler work but called back next day to arrange a call with an engineer. I concluded that there was No further Action.

 

I have spoken with my local Daikin Engineer and they can offer two 10 kW systems but they would be splits and as underground pipework is 15 year old likely have to repalce and dig a new channel to house. (Will have to do this for a monobloc anyway).  Then have the internal unit noise as well as maintenance costs on two units.  

 

I asked Mastertherm in Wales to see if they could specify anything They offer Master Therm Czech made Units. They said they could supply a monobloc 7-22 kW system but I would need a local installer. Installer checked and says it is 22 kw at warmer temperatures and  for houses with heat loss up to 16kW.

 

Brendon from Heacol has visited and we are finalising the details on a monobloc system that can be installed in January.

 


   
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