adding an airsource heat pump, supply problems

[Richard Burns]

I would expect the quotation may well have said "subject to suitable supply available", however a good company would have assessed the likely demand for their equipment in the same way as any electrician installing say a new shower would check if the supply was up to it and included this cost /caveat in their quote.
It certainly should not be discovered after first fix, but there is the consideration that there was no supply available to assess.

 

[Engineer54]

The information you have given from Rob Baker only shows 64A, your house supply will not rise above 60A in all likelihood at any time.
The air source heat pump seems murderously inefficient if it is only managing to supply about 50% of the heat from the air source they should be at about 3-5 times the power input and have a supply requirement of say 16A at max this would then (assuming all the back ups and boosters were required to run at the same time) give about 40A total

Never come across any of these fancy heating pump systems actually save money, come across plenty that have increased heating costs though!!

 

[Rockingit]

Never come across any of these fancy heating pump systems actually save money, come across plenty that have increased heating costs though!!

I've done quite a few GSHP and ASHP systems in the last couple of years, and it does all seem to be smoke and mirrors when inside the box is basically just a series of 2 & 3kW immersion elements waiting to kick in on 'back up'.

As to the OP, well the worst ones of these that I've done was a 12kW GSHP to a large property with lots of outbuildings, the DNO TX was 16KVA, incoming fuse was 80A and the official max demand calculation after all diversities had been allowed for was about 220A if I remember right. It ran, it ran fine, and at no point did I ever see my clamp meter get over about 40A's in a dry test. Ironically, however, the DNO DID have to come and replace the TX to a 22KVA one as even under a no-load situation it was suffering from brown-out badly which was very noticeable with all the LED lighting. What I mean by that, btw, is that having disconnected every circuit at the primary board except for one solitary 13A plug-top - so we're in effect tails > 13A - and then using a 1200W power tool as a test load with an analogue meter across the voltage, when you gunned the tool the meter dropped way below 215V which clearly wasn't right!!

Subsequent to all of my installation, they had a 4KW PV system added last year to no ill effect either.

 

[JD6400]

I have been involved in between 25 - 30 ASHP - GSHP installs over the last 8 years or so , and I would not touch them with a barge pole personally .
I would say that GSHP is the best of a poor choice to be honest , but still seems to need what seems to be endless maintenance and replacement parts , from what I have seen of them after around 5 years of service .

I have also seen two new upgraded supplies being needed after they have been turned on , only to blow the main fuse after a short time !

One was on a job we were not involved with and the other one was as a result of the so called mechanical / electrical engineer rather rudely and some what condescendingly questioning my ability to basically add up , and then ignoring our concerns !
That one needed nearly two and a half miles of new cable being laid at a knock down cost of I think around £70k , and to boot they paid the ----er for his flawed advise as well !?

 

[Knobhead]

If you use the forum search there’s a good thread about this. I can’t remember the outcome but it did get messy with the heat pump guys and the DNO.

 

[Rockingit]

If you use the forum search there’s a good thread about this. I can’t remember the outcome but it did get messy with the heat pump guys and the DNO.

If that was my thread, it was Rockingit 1 - Others 0. Not that they ever came back and apologised for being wrong at every stage, clearly. Which reminds me....I never DID look into claiming against the M&E chaps Professional Indemnity Insurance for all my wasted time........

 

[Knobhead]

I thought it was someone I knew. If I recall right it was a split phase supply.

The OP was getting their hair off at some point.