Aircon

[Geoffs]

My aircon packed up about 2 years ago. Compressor won't run. I've been struggling to find someone to look at it. It's about 10 years old, made in Florida, and the makers have gone out of business.

Anyway I've found an excellent chap who knows these systems inside out. He's disgnosed a failed, open circuit, pressure switch. This is just in series with 230volt supply to the compressor, so it won't run. He bridged out the switch to see if compressor will run, and it does. Not good to leave it like that, so need a new pressure switch.

Trouble is, apparently, most modern systems are 'digital', which means pressure switches are only rated with low voltage contacts, not suitable for 230v. My engineer has tried all his sources and is having trouble locating a suitable switch.

Eventually located one in USA, delivery was promised yesterday.. It didn't arrive ! It's now promised for next week, but........

So, question, anyone know of air con spares supplier who can supply a refrigerant (R22) pressure switch rated for 230v . A long shot, I guess, but worth a try.

If worst comes to worse, can rig up a circuit with a relay, but not ideal.

 

[jrudge]

Just put a relay in the mix that will take the current. Probable cost £5 off eBay.

 

[Geoffs]

Just put a relay in the mix that will take the current. Probable cost £5 off eBay.

Yes, thanks, that's what I'll do if pressure switch doesn't turn up. It's just that it's another component in the system that can, potentially, go wrong.

 

[Adethefridge]

There are several HP switches available in the refrigeration indusrty from cheep fixed pressure button type, I would suggest an adjustable pressure switch either manual or auto reset Ranco have a wide range and are available from any refrigeration wholesaler you will require a fixing plate and pressure coupler to install it, from memory they are rated @ 20amps hope this helps

 

[superheat6k]

We have in stock a Johnson manual reset P100 range rated at 26 Bar for the discharge line (hot pipe), and might have an auto reset 2.5 bar for the suction line (cold pipe).

PM me for details if you want these, but they would be chargeable through my business.

As safety cut outs for an R22 system these will be just fine.

The switch details are here - for R22 read R22, but IMHO 4 bar is too high for LP on an R22 system and will cause nuisance trips, so the R134a 2.5 bar would be more suitable.

http://www.johnsoncontrols.co.uk/co...tion_components/pressure_controls/en/P100.pdf

When fitting the switch undo the old and do up the new rapidly to avoid loss of gas, as you cannot legally recharge R22. The fitting should have a schraeder valve. The standing pressure at 15oC is about 6 bar, or 90 psi, so make sure the gas stops hissing before you completely unscrew it from the thread - getting the fitting back on with 90 psi streaming out is not at all easy.

If the gas does leak out uncontrolled get out of the space quickly - not toxic, but it is an asphyxiant. If it comes out in liquid form avoid getting it on your skin as it can easily cause a cold burn. Venting gas knowingly is an illegal act, but changing a pressure switch on a live system with a schraeder is perfectly ok if a small puff releases. If in doubt find a Fridgy to fit the switch for you.

 

[Geoffs]

Thanks Superheat, I passed on your info to my aircon engineer.

What I didn't make clear in my original post, is that the unit is a high pressure switch, don't know if that makes any difference to your comments.

Thank also for your safety tips, but I wouldn't dream of tackling a high pressure fridge circuit myself, leave into the professionals.

Thanks again for your help

 

[superheat6k]

Thanks Superheat, I passed on your info to my aircon engineer.

What I didn't make clear in my original post, is that the unit is a high pressure switch, don't know if that makes any difference to your comments.

Thank also for your safety tips, but I wouldn't dream of tackling a high pressure fridge circuit myself, leave into the professionals.

Thanks again for your help

The HP switch is the one I mentioned rated for 26 Bar.