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Help me keep the faith with my air source heat pump installation

AdamK · 2025-03-29T13:05:20Z

i knew when setting out on this road it would be a challenge i just didnt know how much of one it would be. after having many quotes some i couldnt fathom why they were so high i thought id sorted an installer. problem is they are 72miles away so first issue was doing a remote heat loss which has been back and forth several times to get it more or less correct, but still have one room thats 2m2 smaller than what i measured. anyway the next issue was getting the 28mm primaries in before the new kitchen ceiling goes in. they sent a plumber that proceeded to bugger the job up as the wall sleeve kit hadnt been supplied to him. so sent him on his way. was promised the sleeve kit the next day and i said my plumber could fit it to save them sending an engineer. next day no kit. add to this all the mods im having to do to pipe work to maximise efficiency and im seeing why the take up is tiny in the UK. im not naming the company as they are a recommended one and have apparently done good work else where but maybe thats in there local area. i know living in Boston creates its own issues being miles from any proper trades so if someone asked me would i recommend getting a heat pump in my area id have to say no. theres just not enough skilled trades where i live.

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Air Source Heat Pumps (ASHPs)

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ASHP-BOBBA

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30/07/2025 11:10 am

@jamespa Hi James, I missed one essential thing with all that, I should of added the way round this is to alway fit a sub board already stocked with a RCD Type B and then cary all of the RCBO C type that are 16, 20, 32 amps all in the same make such as FuseBox for example only "not sponsored" that way the only thing you need to find on the shelf is the AAB old normal MCB thats a higher rating then the RCD in the new sub box to feed it or take the power straight from an existing splitter.

I agree with everything you say above fitting the correct fuse to the correct manufacturer, I just forgot to mention what I meant by stock the solution for all ASHP's is stock ready made sub boxes with the correct Type 2's already in.

Also thanks for the support on the balancing of views, you are correct that most people with good installs are just getting on in life 🙂

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AdamK

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Topic starter 30/07/2025 3:52 pm

@editor here's some pics.

One is a straight Flexi that has been bent twice and presses against the wall. The other is a straight with a built in hard 90 on the end.

This is my external CU.

This is one from the heat pump training centre where I work. Tom Baines at Vaillant who I'm dealing with has seen the these 2 pics and the college one is correct, mine is not.

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AdamK

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Topic starter 30/07/2025 3:54 pm

Another angle. The pipes are bending and the insulation is being crush on one of the wall brackets.

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AdamK

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Topic starter 30/07/2025 3:58 pm

@editor actually looking at the college pic and my pic unless the surge protector is in the RCD, they won't be able to fix my problem as it would need a 7 way board.

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JamesPa

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30/07/2025 4:13 pm

Posted by: @adamk

↑

@editor actually looking at the college pic and my pic unless the surge protector is in the RCD, they won't be able to fix my problem as it would need a 7 way board.

They could hang a secondary CU off the existing ASHP MCB and then put the RCD in that - as @ashp-bobba suggests above I believe.

They may argue that its wiring-regs compliant as it is (which I think is the case) albeit that its not compliant with Vaillant instructions.

As it happens I was quite happy for my electrician to do something similar for essentially the same reason (insufficient space in the CU for an RCD, no RCD and no RCBO available to fit). My CU will be replaced anyway within a few years when I change the gas hob to electric (which will be when I redo the worktops) and get a bidirectional EV charger, at which point I will run out of options to fit any more into the existing CU. However I concede its not best practice so Im neither advocating nor defending it; I just hate to use more materials than are needed if I know they will be thrown away before the end of their useful life.

This post was modified 6 hours ago 7 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

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