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Mitsubishi Ecodan 14kW ASHP costing £450-£550 per month to run

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Air Source Heat Pumps (ASHPs)

Last Post by Derek M 4 years ago

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marknhudson

(@marknhudson)

Eminent Member Member

Joined: 4 years ago

Posts: 15

Topic starter 28/12/2021 10:19 am

I'm new to this forum (and any online forum for that matter). I'm at my wits end with an ASHP that's costing over £450 pcm in a new build home (Oct & Nov). December is on course for £550 for the month according to the smart meter. Despite assurances from Mitsubishi and independent experts that I'm set up correctly I can't believe that's true.

I have a Mitsubishi Ecodan 14kw ASHP

Underfloor heating downstairs

Rads on 2nd and 3rd floor in a 5 bed house approx 3000 square foot home.

House build in late 2018.

Please could you point me in the right direction for some advice?

Thank you

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prjohn

(@prjohn)

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Joined: 5 years ago

Posts: 125

28/12/2021 11:39 am

Hi, Welcome to the forum. Just a couple of questions to get started.

Was the HP installed when the house was built or was it an add-on after the house was built?

What is the energy requirement as per EPC?

Do you know your heat loss calculation?

What temperature are you heating the house to?

Are the temperatures of the top floor radiators hot?

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Derek M

(@derek-m)

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Joined: 5 years ago

Posts: 4427

28/12/2021 11:57 am

Posted by: @marknhudson

I'm new to this forum (and any online forum for that matter). I'm at my wits end with an ASHP that's costing over £450 pcm in a new build home (Oct & Nov). December is on course for £550 for the month according to the smart meter. Despite assurances from Mitsubishi and independent experts that I'm set up correctly I can't believe that's true.

I have a Mitsubishi Ecodan 14kw ASHP

Underfloor heating downstairs

Rads on 2nd and 3rd floor in a 5 bed house approx 3000 square foot home.

House build in late 2018.

Please could you point me in the right direction for some advice?

Thank you

Hi Mark,

Do you know how your system is being controlled? Do you have thermostats and TRV's? Is the FTC controller set for weather compensation control? If you are not certain then post a photo of the controller screen.

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marknhudson

(@marknhudson)

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Joined: 4 years ago

Posts: 15

Topic starter 28/12/2021 12:32 pm

@derek-m Thanks for coming back so swiftly.

Do these pictures help? We have 6 underfloor heating zone controls on the ground floor as pictured and then a control on the first floor for the rads plus the main control hub in a closet as pictured.

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marknhudson

(@marknhudson)

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Posts: 15

Topic starter 28/12/2021 12:36 pm

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marknhudson

(@marknhudson)

Eminent Member Member

Joined: 4 years ago

Posts: 15

Topic starter 28/12/2021 12:36 pm

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marknhudson

(@marknhudson)

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Joined: 4 years ago

Posts: 15

Topic starter 28/12/2021 12:36 pm

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Derek M

(@derek-m)

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Joined: 5 years ago

Posts: 4427

28/12/2021 12:56 pm

Hi @marknhudson

Please press the F1 button and let me know what the displayed temperatures are reading.

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marknhudson

(@marknhudson)

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Joined: 4 years ago

Posts: 15

Topic starter 28/12/2021 1:14 pm

@derek-m Hi Derek, I've pressed the first of 4 buttons but the display doesn't change much. Just showing this...

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Derek M

(@derek-m)

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Posts: 4427

28/12/2021 1:32 pm

Hi @marknhudson

Do you know how to check and/or adjust the weather compensation parameters?

Do the radiators get warm to the touch?

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marknhudson

(@marknhudson)

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Joined: 4 years ago

Posts: 15

Topic starter 28/12/2021 1:44 pm

@derek-m Not sure but I can have a play around with it. Is there some setting that it should be set to?

Rads get warm but never hot

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Derek M

(@derek-m)

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Posts: 4427

28/12/2021 3:42 pm

Hi @marknhudson

Warm is okay, cool is much better for improved efficiency.

It would appear that the 'Information' screen is not available if you have 2 zones set.

Press and hold the 'Menu' key for 5 seconds and then select Heating/Cooling. Press 'F4' key and select 'Zone 1', then press 'F2' or 'F3' to view the actual parameter settings. Since I don't know the heat loss for your home you could try adjusting to the following:-

Set the water flow temperature to 45C at an outside air temperature of -10C, and a water flow temperature of 25C at an outside air temperature of 18C. Confirm the settings, then check the values for Zone 2 and adjust if necessary.

👍

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