Air Source Heat Pump, Fault Finding.

[Andy™]

If we done a link up it may be possible to get it to Andy's for you,

Might take a couple of years though,        ,,,,,,,,  

half way probably isnt much use to him

 

[ProDave]

The block is only 5 years old and all of the flats had the same model installed.

The other owners we spoke to said they were told that model is long out of date and the company who istalled them has folded. The impression was it had being usual developers cheap lash up.

The owner of the one I looked at said his electric bill since he had been there was very small. He did also say there has never being enough decent hot water to fill a bath.

I feel it is ashame not to replace it with a better model, but a lack of trained inStallers makes it difficult. I can understand that after a week of no hot water he just wants rid of it.

That says a lot about the problems.

You need to understand what a heat pump does, how it works, and then design a system to use it properly.

The first thing is to understand that a single stage heat pump (which this almost certainly is) will not heat water sensibly to much above 45 degrees. So on it's own, a heat pump is unlikely to provide a satisfactory source of domestic hot water.

They work great for heating the low temperature water for under floor heating, and for pre heating domestic hot water, but need to be used in conjunction with something else to heat the domestic hot water to final temperature.

One workable solution that a lot of low energy house builders are using is simply to use a 10KW modulating instant water heater to boost the DHW to final temperature. That can work well and be surprisingly efficient.

I suspect this unit (and the others in the block) have failed is because it was being asked to perform well outside it's design spec.  Far too many builders think you can simply swap a boiler for a heat pump without changing anything else.

 

[Tony S]

Its a story of you get what you pay for with heat pumps and a lot of heating manufacturers have jumped on the band wagon making them, most being rubbish.

ASHP’s have been around since the 1930’s. Admittedly they were mainly American. Someone in the UK must have got it right by now.

I looked in to installing a GSHP in the 80’s, the wife snarling at me put paid to that idea.

 

[Tony S]

As I say I’m trying to dissuade the guy as I can see things going badly wrong and I’ll get dragged in to it.

The GSHP I was looking at all those years ago was American but as I said, the wife snarled at me so the idea was ditched.

I went for combined gas/electric with the help of the then NWEB. That didn’t cheer her up either as the floors had to come up once again.

 

[pewter]

This one goes to 55C,   though when looking at it there was a thermostatic mixer between cold in and hot out of the tank feeding the flats hot taps. I wonder if it was set correctly. The element in the tank could be set to come on to make the tank a bit warmer.

The Tank is stainless with the the central heating water that flows from the heat pump acts as a jacket to the hot water i think.