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My ASHP Installation: Mitsubishi Ecodan 14kW

Kev M · 2021-03-19T18:06:36Z

Our ASHP is being installed 5th April I thought it might be of interest to others to hear how it progresses. It's all become real because we have the confirmed installation date and the ASHP is being delivered direct to my house on Monday 22nd. Some details. We live in a 1990 165 m2 4 bed bungalow. Insulation is quite good and we are also getting new windows and doors in the next few months. Heating now is 8 storage heaters, one wood burner, one SF stove, 2 electric towel rails, one electric UFH system in an ensuite and a couple of portable electric heaters for occasional use. HW is E7 immersion and electric showers. As you would expect, electricity bills are high. We haven't lived here a whole year yet but I reckon £1800 a year and it's only that low because there are only two of us (and of course we've had no visitors!). We will use less wood and coal too as the stoves change from necessities to nice to haves. We are using a company called JL Phillips, based in Newark. They are doing the whole installation including the ASHP, cylinder and 12 radiators split into 2 zones. They have done an initial quote (with the price) and a full survey. I'll get the results of that, including the heat loss calculations and radiator specs, next week. We are having a Mitsubishi Ecodan 14kW ASHP and a 250L Heatrea Sadia Mega flow cylinder. Our requirement was calculated at 11kW so we could have gone for a smaller ASHP but they recommended the bigger one. In preparation I've been removing storage heaters (most of the rads are going in the same locations) and I've just laid a concrete slab outside for the ASHP. We have plenty space and our nearest neighbours are 30-40m away. It's going outside the kitchen and well away from bedrooms and living room. Although we live in a conservation area, our ASHP falls within permitted development so no planning permission is needed. The RHI was a big incentive for us. It will cover about 70% of the cost and I hope savings will cover most of the rest. I doubt we would be getting an ASHP without it so it has done its intended job. That's about all for now. I'll update this thread as things progress. Next event should be the ASHP arrival on Monday. Which reminds me, I need to clear a space in the garage!

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Saz

(@saz)

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25/10/2021 7:09 pm

I had the electrician back out today to look at the immersion, as I had reported it coming on alongside the heat pump during regular heating of the hot water and underfloor/rads. He took one look at the meter, which shows a low reading in his eyes (well yes because it's been off more than because of various repairs, plus I only turned the heating on a few weeks ago!) and refused to do anything else. I have videos of the immersion coming on (lights flashing on the meter) alongside the heat pump when heating hot water and UF/rads but he refused to look at them or entertain the idea that Vaillant posited of putting the immersion on it's own spur. The Arotherm plus is more than capable of doing the legionella cycle on it's own due to the refrigerant used, as all there advertising says, but instead I am being forced to use the immersion and not have any control over it, or at the other times it is coming on too. It is so mild outside too. He did not look at any settings on the controller either.

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MikeFitz

(@mikefitz)

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Posts: 29

25/10/2021 9:59 pm

@saz I am also concerned that my recent installation is using the immersion top heat up the water. My non ASHP electrical use has rocketed but I am only using 2 Kwh per day to heat a 250 litre tank.

I have turned off the immersion at the fuse box so I can see if its been eating up the electricity

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Saz

(@saz)

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Joined: 4 years ago

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25/10/2021 10:22 pm

@mikefitz Hi, and these systems shouldn't need to even use the immersion at this time of year I think? It's a good idea to do comparisons, that's what I intend to do. I'm so annoyed with the electrician and his attitude, extremely unhelpful to say the least. Total waste of time.

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Kev M

(@kev-m)

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Topic starter 26/10/2021 12:16 pm

@saz, @mikefitz, I believe that some ASHPs have a setting that determines when the immersion heater kicks in. On another forum I read, someone said theirs was set to use the immersion whenever the flow temp exceeded 40 degrees. I've no idea if that's possible with your systems but it would be worth a look at the settings/manual.

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Mars

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27/10/2021 4:28 pm

"Standard" low temperature heat pumps are designed to be efficient up 45C. The immersion is there to get the temperature north of that, and to help with legionella cycles. Our HW is set to 44C. For most people that water feels very, very hot on the skin. Anything hotter than that will be start to feel uncomfortable so you'll turn the cold water on to offset this. As far as I know, most systems are set up for the immersion to kick in when the temperature requirement is over 45C (or maybe 50C). Up to that point, the heat pump should be heating it.

This post was modified 2 years ago by Mars

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Mars

(@editor)

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26/02/2024 9:59 am

I’ve just re-read your installation post @kev-m (over the first couple of pages) and I have to say it went really well, and it’s worth reading for anyone considering a heat pump installation. How involved were you in the process?

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