15 year old Daikin ASHP System
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 ?
I have no connection with them whatsoever but why not ask Brendon at
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 Solar thermal. 9.5kWh Givenergy battery with AC3. MVHR. Vaillant 7kW ASHP (very pleased with it) open system operating on WC
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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.
Before and after pictures. Old Daikin System ( 2 x 16 kw) split with 700l Buffer.
New Panasonic system 25 kw mono bloc with volumiser and thermo syphon system for log stove back boiler.
Really appreciate the lack of noise from the split units in the house. Two new radiators in the far side of the house
Brendon and Jordan from Heacol have done a great job designing and installing the system.
Upstairs now at 17 to 18 C and downstairs at 20 to 21C when outside at 0C. NB in all rooms unlike before.
Installed from mid January but commissioning delayed as storm Eowyn knocked out electricity to area.
Some tweaking heat curves to get to the ideal.
This was one of the first of the new large M series Panasonic units in the country and it is a beast of a unit.
s
Awesome!
Its good to read you’ve got the performance you want and sad that this wasn’t the case previously and it needed 2 new radiators to achieve that.
Please update us when you have enough data to compare the costs. But if you’re warmer than previously then it’s not a direct comparison.
Great to read it’s been successful!
2kW + Growatt & 4kW +Sunnyboy PV on south-facing roof Solar thermal. 9.5kWh Givenergy battery with AC3. MVHR. Vaillant 7kW ASHP (very pleased with it) open system operating on WC
Thank you Judith - COP on the heating is showing as 2.7 (slightly lower on DHW).
To take an example
Electricity usage is shown on ASHP for Sunday as 69.5 kWh for heating and 9.0 for DHW. Total 78.5 kWh.
Smart meter shows total energy usage on Sunday for the house was 101 kWh so calculation says we used 22 kWh for domestic purposes - Ofgem suggest it should be 11 for a modern house. Needs investigating...
Smart meter is dumb and resets in the early afternoon around 2 pm rather than at midnight.
Did not charge the car on Sunday and it rose to a sunny 5C outside.
Our new ASHP system was installed in mid January and for the first time in 16 years the house has been consistently warm - especially my home office where previously even mid summer required a pullover.
We have not had to use log burner in several weeks.
We have upsized two radiators, relocated one, added one for thermosyphon and found out that underfloor heating valves were not fully functioning.
Downstairs is a consistent 20 to 21 C and upstairs 17.5 to 18 C.
COP was 3.4 today.
The plant room has been returned to a utility room that means everyone is happy.
Brendon and Jordan from Heacol have been with us throughout and have consistently stepped up to improve the system and resolve any niggles.
This included replacing the Panasonic awkward in line filter with one in the plant room, adding open source accurate monitoring and also adding an interior thermometer so that the unit reacts to house inside temperature rather than flow temperature. A comms issue with the outside unit that required a temporary walk around was resolved quickly today.
The unit is accurately responding to outside temperature in both flow temperature and energy required.
In the Aquarea app screenshots the yellow is heating and orange is DHW. The black line is outside temperature.
Yes this is a big house with a big heat loss but we now have a system that works and we expect running costs to go down vs the 2 x 16 kw systems.
Thanks Judith for suggesting the intro and Mars for this interface.
Thanks Heacol for working continuously to design the system install it and make it work seamlessly.
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