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Grant aerona 3 Weather compensation parameters

Air Source Heat Pumps (ASHPs)

Last Post by bretix 3 years ago

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Sprincey

(@sprincey)

Active Member Member

Joined: 3 years ago

Posts: 3

Topic starter 10/12/2022 3:46 pm

I and in UK and have a Grant aerona 3 and just trying to get the most warmth out of the system as we are now entering the winter months.

I am just wondering if anyone has advice on the most suitable Weather compensation parameters to set or I should set the system to a Fixed Set Point?

Any advice is much appreciated.

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Derek M

(@derek-m)

Illustrious Member Member

Joined: 5 years ago

Posts: 4427

10/12/2022 4:00 pm

Please provide more details about your system.

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Sprincey

(@sprincey)

Active Member Member

Joined: 3 years ago

Posts: 3

Topic starter 10/12/2022 4:15 pm

@derek-m Hi the Grant aerona 3 is used to heat the house and supply hot water. Nest thermostat placed in the living room is used to control everything.

serviced two weeks ago and temperature has just dipped and water in the radiators is tepid at best.

Hope this helps.

Best, S

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Derek M

(@derek-m)

Illustrious Member Member

Joined: 5 years ago

Posts: 4427

10/12/2022 6:26 pm

Posted by: @sprincey

↑

@derek-m Hi the Grant aerona 3 is used to heat the house and supply hot water. Nest thermostat placed in the living room is used to control everything.

serviced two weeks ago and temperature has just dipped and water in the radiators is tepid at best.

Hope this helps.

Best, S

What is the model number of your heat pump? Do you have user and installer manuals? What is the size and heat loss of your home? Do you have just radiators or also Under Floor Heating (UFH)? What are the desired temperatures in your home? Are you achieving the desired temperatures? How much electricity are you using?

If your radiators are only tepid then I suspect that your system is operating in Weather Compensation (WC) mode, which should be the most efficient. If your rooms are not achieving the desired temperatures then your system would appear to require some adjustments.

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HughF

(@hughf)

Noble Member Member

Joined: 4 years ago

Posts: 489

10/12/2022 6:27 pm

You need to set your weather compensation to something reasonable. I’d go for 47@-3 and 37@15

Turn the nest up to something high like 30 and leave it there, having an external thermostat isn’t doing you any favours at all and it needs to be removed from the system ideally.

Can you let us have your heat loss calculations, these should be available from your installer.

Off grid on the isle of purbeck
2.4kW solar, 15kWh Seplos Mason, Outback power systems 3kW inverter/charger, solid fuel heating with air/air for shoulder months, 10 acres of heathland/woods.

My wife’s house: 1946 3 bed end of terrace in Somerset, ASHP with rads + UFH, triple glazed, retrofit IWI in troublesome rooms, small rear extension.

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Sprincey

(@sprincey)

Active Member Member

Joined: 3 years ago

Posts: 3

Topic starter 11/12/2022 4:07 pm

@hughf Added the settings you recommended and seems to be a lot better, I will look into what to do with the thermostat as well.

All a learning curve for me and thanks all for your help. Much appreciated.

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HughF

(@hughf)

Noble Member Member

Joined: 4 years ago

Posts: 489

11/12/2022 6:21 pm

Chofu-Operating-Installation-Manual.pdf

Attached is the Chofu user manual for your heat pump. It might be helpful.

Off grid on the isle of purbeck
2.4kW solar, 15kWh Seplos Mason, Outback power systems 3kW inverter/charger, solid fuel heating with air/air for shoulder months, 10 acres of heathland/woods.

My wife’s house: 1946 3 bed end of terrace in Somerset, ASHP with rads + UFH, triple glazed, retrofit IWI in troublesome rooms, small rear extension.

👍

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bretix

(@bretix)

Estimable Member Member

Joined: 3 years ago

Posts: 85

12/01/2023 10:49 am

@hughf

This is feally useful info and wondered if can you help to improve any of my settings?

I've switched on the WC and left it at that so assuming it's set at default mode at 19c using a nest and set at the control remote too and not getting cycling spikes like I had before.

Heat loss calculations are (or rather were)

31025 for heat

3172 for water

They calculated I would spend £1759 per year on total renewable heating/water 🤣 at a flow temp of 50c albeit 15p/kw when they did it.

I can't accurately work out cop and heat pump use so using a third party app can see I'm using in total between 1.5 to 2kw per hour during the from 7 until MN.

What could I need to tweak to potentially make any savings while keeping comfortable?

ie is it the water going out temp at min and max I need to adjust?

I've tweaked the hot water to overnight cheaper tariff with legionella protection set 65c for 2 hours, and for 1 hour set at 55c to take advantage of PV between 1145 and 1245.

2 10kw Grant Aerona3
Heat loss calc 16.5 kw @ -2.8 degrees
4.32 PV

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