Bizarre Retro-fixes by AAC

ASHP-BOBBA · 2025-10-09T19:45:24Z

For educational purposes only: We will share some of the retofixes we complete and explain how we worked it out, how we fixed it and hopefully later how it performed. We will also share if we failed but gave it our best shot or found in the rare case that it is unrepairable so we had to concede.

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Air Source Heat Pumps (ASHPs)

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ASHP-BOBBA

(@ashp-bobba)

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Topic starter 10/10/2025 8:05 am

@jamespa The client will be perusing and reporting, we will keep our usual stance and concentrate on resolving the mechanical issues, I have seen some real bad installs and I would be the chap you meet that says yer yer we seen it all and just when I think I have I am knocked off my feet again and again.

So we have now quoted the repairs this morning to correct this and sent it over, my colleague from the office has already called me as I am at home and said she feels so bad for that client can we not reduce the rate further or do this one for free. Its so wrong and so bad it even makes us feel bad for all the clients.

AAC Group Ltd covering the Kent Area for design, supply and installation of ASHP systems, service and maintenance, diagnostics and repairs.
Professional installer. Book a one-to-one consultation for pre- and post-installation advice, troubleshooting and system optimisation.

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JamesPa

(@jamespa)

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10/10/2025 8:19 am

@ashp-bobba

No reason you should feel bad. This case is particularly worrying because, so far as I can tell from your description, it's not heat pump specific and something very similar could have happened with a boiler based system. So far as I can tell the main horror is to do with plumbing of uvcs Vs vented, which surely every single plumber should either be completely familiar with or avoid completely.

This post was modified 2 months ago 2 times by JamesPa

4kW peak of solar PV since 2011; EV and a 1930s house which has been partially renovated to improve its efficiency. 7kW Vaillant heat pump.

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ASHP-BOBBA

(@ashp-bobba)

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Posts: 313

Topic starter 10/10/2025 8:23 am

So one of the best but simple mistakes I have ever seen by a big HP company was on a new housing estate where there were 4 ASHP side by side in a compound serving a cluster of 4 homes, nice install and good workmanship. These 4 homes all complained about wild swings in in temp and non responsive ASHP, low flow, low pressure and many other fault codes.

The installer attends resets all 4 systems, tells them all go full heating and they run like a dream. 1 days later all fails.

Returns attends, resets all 4 systems, tells them all go full heating and they run like a dream. 1/2 day later all fails.

All 4 systems get new controls and nothing changes, anyways visit after visit they cant resolve it, then they call us. We attend and ask a few simple questions and within 1hr of chatting and we all know I love a chat, I said so, the chance off all 4 systems having ghost issues is rare, the chance that all the units come from a bad batch is very rare and the chance that human error caused this issue as its been like this form day 1 commission is almost guaranteed. I bet you commissioned them by turning them all on at the same time and by telling them all to heat the water then heat the home yes? yes! so chances are you have piped or wired or both each unit to the wrong home cylinder. What causes this kind of error is the belief that ones self or colleague is such an expert that they could never make such a mistake and therefore it is never considered, everyone forgets they and we are all human.

So what happened was simple. Unit 1 was wired to 2, unit 2-3, unit 3-4 and unit 4-1, all the cables had shifted one unit across and the costs and investigation was amazing up until this point.

We charged our £100 for the chat and they were forever grateful. It is kind of nice being a boring contractor popping in a couple ASHP here and there and then on another day putting on our expert hat and seeing a different kind of respect from our colleagues in the industry.

Our leading industry award is happy customers not Installer Show stuff and I intend to keep it this way.