Air Source Heat Pumps

richardc1983

An update:

UPDATE:

The unit had a leak, at 2 of the flare nuts from the originally installed units from 2yrs ago.

The system was running with about 460g of refrigerant when it should have had in 2330g but was working fine in cooling!!

The guy who came out was great, did everything the right way.

Im so annoyed with the guy who fitted the 3rd unit, whilst his pipework was neat and no leaks from that his poor skills and refusing to weigh out the refrigerant properly by removing it all then weighing back in has meant that yes he added 640g to the measly 460g that it had left in it but did not detect the leaks etc and kept saying the system was performing well when clearly to anyone in the know who has any sense about them I knew it was not!

Unit now ramping up nicely and running at nice air offs and achieving nice hot temperatures... At least!

and I shall now breath and can relax knowing that I have found someone decent to service my units and who deserves more business due to doing things the right way.

He added in 2330g as per LGs intruction on the phone. Not sure how you guys are working out the 2180???

Charged me £130 to sort out that was all work in and he was here from about 10am only just left at 2.

thechippy

Glad it's sorted,

I had a hunch it was all down to the refrigerant charge.
I keep getting 2 different base charge figures from the lg site. One shows 2000g and one shows 2150. I should have said to you earlier that it could probably be varified by looking at the outdoor unit data plate.

Nipping out now, so spk later....;)

richardc1983

ive just edited my reply, not sure how ur getting the 2180 when it should be 2330 based on 2000kg.

thechippy

richardc1983 wrote: »

ive just edited my reply, not sure how ur getting the 2180 when it should be 2330 based on 2000kg.

Ok,

To put it as simply as I can.

Your base charge allows for the first 7.5m of combined pipework. Your total run is 39m, so the trim charge is based on 31.5m.
20g per m minus the correction factor of 450 = 180g

I got conflicting base charge spec from LG. One data sheet said 2000g and one said 2150g.

We simply need to confirm which one it is, which should be written on the data plate on the outdoor unit.

If it is in fact 2000g then your total charge should be 2180, but if it's 2150, then the total charge will be 2330.

If it turns out that the base charge is 2000g and your guy has put in 2330, what's probably happened is he's claculated the trim charge on the 39m rather than 31.5m.

39 x 20 = 780. Minus correction factor of 450 = 330.
2000 + 330 = 2330.

Are you with me?

Worst case is you may have an overcharge of 150g. This is not an issue, the system can cope with that ok.....;)

Tried to buzz you, but no answer, so will pm home number. Don't call me between 8 and 8.30 pm though, as I'll be watching Eastenders like the sad git I am.......:rotfl:

richardc1983

Well to conclude today, ive realised how important it is to have a yearly service as this picks up things such as leaks etc which could lead to compressor failure and such problems as undercharge.

I have had so much trouble with engineers who told me they were doing it that way despite it being wrong and me telling them at today has cost me £140 when it should have been picked up from the start.

To anyone with these systems, whilst its possible to clean ur own coils and the fans and filters etc, you need proffesional equipment and scales etc to detect leaks and pressures etc.

Hope some others can benefit from my advice.

Andy_WSM

Glad you go this sorted Richard. I nearly went the multi-split route myself when I was looking at various options. How is the system working in this cold, wet miserable spell of weather?

richardc1983

Hello Andy, system is working fine now plenty of heat and reaching set points easily. Multiple split is good if u are going to be running all indoors a once. This is more efficient as you only have one compressor running.

eugeneg

I have an 11KW NIBE ASHP installed in a 3 bed detached house. The NIBE rep came around and suggested that I insulate underneath the suspended wooden ground floor before the new carpets go down. Is this OTT ?
A possible insulator to push up between the joists may be [FONT=&quot]wickes.co.uk/Easy-Fit-Insulation-Board/invt/210020 [/FONT]

Cardew

richardc1983 wrote: »

Hello Andy, system is working fine now plenty of heat and reaching set points easily. Multiple split is good if u are going to be running all indoors a once. This is more efficient as you only have one compressor running.

Much as the discussion on problems with your ASHP is interesting, and indeed helpful, I fear it may put many people off ASHPs.

The majority of people want a 'switch on and forget' CH system and it appears that to get the ASHP system operating efficiently, you need a lot more than a layman's knowledge!!

richardc1983

No but if you was going down that route the installers would give you that info!