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Grant Aerona 3 Help please - ECO4 grant

 
Air Source Heat Pumps (ASHPs)
Last Post by Powysperson 12 months ago
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 Powysperson
(@powysperson)
Eminent Member Member
Joined: 1 year ago
Posts: 11
Topic starter 19/02/2025 8:52 pm  

Hello all, newbie here.

I've had the ECO4 grant through the council here in Powys who have a scheme called Warm Wales, the benefits of which we got solar Pv and a battery but the downside we had to have installers of their choice. The installers have gone awol, I presume gone bust, and they still owe me money for finishing the job which is nice. It's a bit of a disaster.

Powys - stone house C1850

Heat loss - I don't know but have attached a screenshot of the heat loss for each room - is this it?

Area M2 Pretty large 4 bed + bathroom upstairs, 3 reception rooms + kitchen downstairs

ASHP - Grant Aerona 3 13kw

Internal Wall Insulation

Solar - Total Installed Capacity (kW): 4.35

Estimated Annual Generation (kWh): 3704.00

Set to:

7am-8am 17°

8am-10pm 18°

10pm-7am 15°

 

The pump itself (Bastion) foir a few weeks has been making a loud intermittent high pitched wailing noise like it's straining against something.

I got an engineer off the Grant website to come out, he serviced it, didn't do anything about the noise as he forgot, then came back to install freeze valves and bypass to try and fix the noise. It didn't work and has got £700 so far.

He changed the flow temp etc so the house is now noticeably cooler but the energy usage higher than ever. We used 60kw of electricity on Monday! Thats £16 a day, I could cry.

We have radbots everywhere but I can't for the life of me work out how to remove them as no other valves seem to fit? Would this sort my woes?

Advice gratefully received please!!

Thank you for reading.

 


This topic was modified 1 year ago by Mars

   
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 AllyFish
(@allyfish)
Noble Member Contributor
Joined: 3 years ago
Posts: 518
21/02/2025 12:17 pm  

Hi @powysperson, first, if you have solar + battery and an SMES2 smart electricity meter + ASHP then get yourself signed up to a variable rate import tariff product. Most of the larger utility providers offer them, such as Cosy Octopus. Set your battery to charge up whenever there is a low rate period, Octopus has 8hrs a day: 4am-7am, 1pm-4pm and 10pm-12am. Shift as much electricity consumption as possible to low rate periods. Become a 'load shifter'. The battery will probably not have capacity to last fully between charge-ups with a 13kW ASHP, and may be limited to 3kW maximum output, but that doesn't matter, you'll save hundreds of pounds each year in the winter heating season. It's a no-brainer. If you don't have a smart meter, enquire about getting one, there may be a wait for installation, if you're very unlucky, your area might not have a good enough signal coverage for the smart meter to reliably work.

Radbots are a new product for me, but they are cheapish electronic TEVs by the look of it. The problem with TEVs (thermostatic or manual) is they restrict flow, and many heat pumps, including Grant Aerona 3, have fixed flow rate. Forget controlling room temperature with TEVs and room thermostats - that's old school and bad. Crack TEVs open to at least 1 number higher than you want the room, so that they purely stop a room overheating. Set the main room thermostat temperature way higher than you ever want the room, 30degC is fine - it should be constantly calling for heating, else it is cycling the ASHP on and off - which is very bad. Control room temperature with weather compensation, which is automatic adjustment of heating circuit supply temperature relative to outdoor air temperature - that's good, very good. The ASHP should just be left to run for long periods with weather compensation enabled to fully warm the fabric of the house and to do it's thing. If you switch the heating off a lot, the house gets cold, and the ASHP has to run more or less flat out to play catch up. It'll consume electricity like crazy doing that.

That high pitched whine? It may well be a bypass valve near the HW cylinder, which will open if the TRVs all close down and restrict the flow too much. Anything that restricts the flow creates noise, turbulence and is inefficient. Sound energy is just wasted electrical energy at the end of the day.



   
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 AllyFish
(@allyfish)
Noble Member Contributor
Joined: 3 years ago
Posts: 518
21/02/2025 12:25 pm  

Video on how to check basic user info on Grant standard controller:

https://www.facebook.com/share/v/1EMrgaHBK6/?



   
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 AllyFish
(@allyfish)
Noble Member Contributor
Joined: 3 years ago
Posts: 518
21/02/2025 12:26 pm  

And one for checking Grant Aerona weather compensation settings. (You may need to join the FB group):

https://www.facebook.com/share/v/1AQBhbLZQu/?



   
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 Powysperson
(@powysperson)
Eminent Member Member
Joined: 1 year ago
Posts: 11
Topic starter 23/02/2025 5:26 pm  

Thank you @allyfish! Sorry for my late reply, I've been working out of the house for the last few days.

It does feel like the ASHP is cycling on and off throughout the day. The radiators feel warm and cold on and off all day, I'm guessing this is bad??!

I've taken off most of the hateful radbots and just left them with nothing on, hurrah!! It does feel a bit warmer and I haven't heard the noise (although I haven't bee here much!) I've had to leave some on so the bedrooms don't get too warm at night. The valve itself doesn't fit a normal valve top sadly so I'll have to source some kind of adaptors.

I just have one normal room thermostat it's set to 18 but you mean I should crank it up to 30 and control the actual temp through Weather Compensation? How do I do that please?

Sadly I'm not on Facebook so can't access those videos.

Thank you so much!



   
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 Powysperson
(@powysperson)
Eminent Member Member
Joined: 1 year ago
Posts: 11
Topic starter 23/02/2025 5:29 pm  

I do have a smart meter and am on Intelligent Octopus Go which is kind of similar?

05:30 - 23:30 26.27p/kWh
23:30 - 05:30 7p/kWh

I set the battery to charge 23.30-5.30 (on the Fox ESS 2.20 app) but have no idea how you can tell when it's discharging.



   
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Toodles
 Toodles
(@toodles)
Illustrious Member Contributor
Joined: 3 years ago
Posts: 2576
23/02/2025 5:40 pm  

@powysperson You should certainly turn that thermostat up above the desired comfort level - perhaps 2 degrees above your preferred temperature. The heat pump controls ought to be set to Weather Compensation mode as this is almost always the most efficient arrangement for a consistent temperature range inside with varying Outside Air Temperatures. You should have a manual explaining how to set the controller for WC and it should provide details or at least a guide on setting the WC ‘curve’.

An open system runs more efficiently than almost any other and that means having all radiator thermostats fully open and using the Lock Shield valves to balance (ie. regulate) the radiator outputs to provide the comfort levels in each room. If this is all new to you, please see my article on balancing radiators:

https://renewableheatinghub.co.uk/how-to-balance-radiators-the-role-of-the-lockshield-valve

Apologies if I am telling you how to suck eggs though!😉 Regards, Toodles.


Toodles, heats his home with cold draughts and cooks food with magnets.


   
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Toodles
 Toodles
(@toodles)
Illustrious Member Contributor
Joined: 3 years ago
Posts: 2576
23/02/2025 5:44 pm  

You will also find many presentations on YouTube (which is a lot less busy or cluttered than FaceBook might be!) for most makes of heat pump, these might well assist you to set up your weather compensation parameters. Regards, Toodles.


Toodles, heats his home with cold draughts and cooks food with magnets.


   
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 Powysperson
(@powysperson)
Eminent Member Member
Joined: 1 year ago
Posts: 11
Topic starter 23/02/2025 5:56 pm  

No, this is awesome help, thank you so much! I've read a fair amount on balancing radiators but this is the only thing that makes sense.



   
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