I have a unit chilled by a danfoss compressor. Had a service company out yesterday who said capacitor probably failed but that not worth trying to replace that as likely to fail again quickly – rather whole compressor required – cost £670.

Am I been spun a line? V hard to get data on this from the web but surely STW can answer?

I work in catering and one of my cold counter unit broke down recently. It needs refilling. The cost was 450 plus vat as it has to be pressure tested.
So 670 for a new compressor is not too bad.

start capacitor I assume? On a single phase unit.

Yes – mind you he did not check anything with a multi meter – judged on the basis of a 30 sec “fizzing” noise (presume from the capacitor) which failed to start the compressor.

Model is danfoss FR8.5G

Totally different application but when the capacitor went on my compressor, I had it replaced for around £50 IIRC. Local compressor specialist rather than an HVAC Co.

I think that’s what I am looking for – a compressor specialist – not in Buckinghamshire by any chance?

always change capacitor and relay 1st otherwise your just burning money

ask the question on refrigeration engineer uk group on facebook,ive got 26yrs experience in fridge/ac but i’m in south wales

if your remotely electrically competent you could go to a climate centre part of the wolsley group, and ask for a replacement electrics pack for a danfoss fr8.5g which would be a like for like swap

thanks DB – I did call them but they said the cap and relay were both special orders. I am sort of electrically competent and will defo try the facebook group. Looks like I should be able to get both these for <£100.

just take wires off capacitor with gloves/pliers or discharge it by shorting it before changing it with mains power off obviously,can give you a bit of a nip otherwise.

Thanks DB – Slough climate centre have the parts – will pick them up Monday and give it a go – cost ca £50 so could work out well. Disappointed the original engineer did not even bother to test them…

prices for compressor work have gone up as the system needs to be emptied and ten re-filled without loosing gas to atmosphere. This takes time and uses more gas , all to do with partial pressures and legislation.

You might get away with a start up capacitor. Relays can gum up with carbon deposits . Isolate then push on the test point a few times with an insulated screwdriver , ifa load of carbon soot comes out that might be an issue.

You might be lucky with just the cap though.

Unfortunately not lucky with the capacitor and relay change – swapped them both out this morning – unless there is some sort of special priming process?
Otherwise have engineer coming tomorrow morning to change the whole compressor.

Checked the circuit? Start at the stat (check made) then the terminals, then thermal overload/klixon. If the klixon isn’t made it’s likely bad news for the compressor.

That is where my limited technical knowledge gets exposed. Not sure where thermal over load or klixon is. Have changed cap and relay – compressor tries to start (slight buzzing noise) but then clicks off. Will wait for engineer tomorrow.
Thanks for all advice