Grant 13kW Aerona3 - issues getting zones to temp

Crimson · 2024-01-16T07:17:28Z

Hi all, New here and looking for some advise. I have a 220sqm property with a Grant 13kW (I need to check if it’s 13 or 17) Aerona 3 ASHP installed as part of a full renovation/extension heating and plumbing redesign. We moved in on 1st December and have never quite had the heating be up to scratch. There are 4 zones each with Heatmiser panels (mainly floor space measures listed not total room sizes) 1 underfloor heating open plan kitchen/dining area approx 44sqm 1 utility with underfloor approx 8sqm Ground floor heated by radiators (Eskimo) - consists of 2x 28sqm living rooms, 1 hall at 16.5sqm, 1 downstairs wc 2 sqm - approx 74.5sqm First floor heated by radiators (Stelrad/towel rads in bathrooms) - consists of 2x 20sqm bedrooms, 1x 18.5 sqm bedroom, 1x 16sqm bedroom, 1x 9.5 sqm bathroom, 1x 3.8 sqm ensuite, 1 Wc 2 sqm, 1 storage cupboard 1sqm - approx 93sqm The downstairs area seems to never hit the desired temp of 21c. I have set it at 21c on and 19.5c off on the heatmiser oanel. Every morning it’s not even sitting at 19.5c. Of note the hall and landing essentially same space so I always wonder if that is an issue as it’s serviced by just 2 radiators between them. All rads were sized according to heat calcs performed by the plumbers. The Grant is running with weather compensation. The plumber/installer came other day and set: 2101: 50c (not sure why set this as that’s the fixed point but keeps referring to the weather curve) 2102: 50c 2103: 35c 2104: -4c And on the panel set to 40c. This improved zones by I reckon 1c but I still never see the downstairs zone hit its desired temperatures. Of note in mornings the rads downstairs never feel as warm to touch as later in the day so I wonder if the system is struggling at coldest points of the day? All radiators have TRVs opened to max. hot water has been an issue too but panel for that has lost power. Seemingly the second time with a power cut. Am awaiting electrician to come and get that back on and check what settings that has. im concerned as can see the electricity meter is flying up and we’ve not got a system working as it should. Can provide more info if needed and photos etc. be good to have some advice as I’m at the mercy of the plumbers who so far on this project have made some blunders so don't quite trust their setup. To clarify this is a Aerona 3 13kW.

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Crimson

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Topic starter 29/10/2025 4:24 pm

And just when I think great they’re coming next week to give this buffer tank install a go. They smash my confidence yet again.

Got a call from one of the installers asking if I could check some measurements of a buffer tank unit against the plant room (they measured on their last site visit so no idea why). He’d provisionally ordered an 80L buffer tank. No way it would fit. So gave him some measurements.

Then proceeds to say ah might need a cylindrical one, will get back to you but YOU may not like the size. Ironic as I’d rather one isn’t installed as the current LLH isn’t doing me any favours…

Next document he sends has a load of options. So I send him some measurements from the plant room and tell him to confirm what one is picked himself as Ive no idea about pipes and placement etc.

How is this industry not properly regulated with these blooming grants from the government incentivising this nonsense.

Truly despair at this now.

Wish never got a Grant unit too, panel is garbage for adjustments, totally not suitable for consumers

The specialist has offered to come back when all said and done to convert a buffer tank to a 2 port volumiser on return, pull out the pump room pump and install the latest panel that works with an app. Obviously that will cost me down the line but now not even sure these guys can get a tank in anyway…

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