MrShades

I've got one of those damn heavy "Portable Air Conditioner" things in the bedroom, that used to work well and get the temps down reasonably well. It's not working quite as it should and I could really use some help trying to fix it (made redundant a few months back so can't just go and buy another!)

When I turn it on it fires up normally (I've got the back off it so I can tell roughly what's happening).

Both exhaust and room fans fire up normally and I set the unit to max fan speed and "cool" - and as per normal after a few seconds the compressor kicks and fires up.

At this point the cooling rad starts to get cold (the pipes at the bottom of it and the rad itself at the bottom are pretty cold to the touch, and it obviously gets closer to ambient temp as I move my finger up the rad). The compression/exhaust rad gets hot to the touch, over much of it, though warmer towards the top, and the exhaust air blows hot.

It runs like this for a while... 30 mins / 45 mins I guess...

Then it stops cooling, and it appears that the compressor just stops. Not because it's hit the set temp (16c!), but just for the heck of it... The rads both start returning back to ambient temp and the exhaust air cools down to ambient also.

If I turn it off at the mains and leave it for 15 / 30 mins and then turn it back on again it runs OK again for a while, and then the same thing happens.

Fortunately there's a wiring / system diagram on the back of the thing (below).

The two M's (fans for cool air and exhaust air) are running fine... it's the C that's playing up. It obviously works (some of the time) rather than just being knackered itself - so my question is, what is the 25uF capacitor doing in here?

Is there a chance that it's the capacitor that's failing/failed, and could it do so like this, after a while (as it 'heats up').

Any idea what tests I could do with a DMM if I could get to the cap / compressor (working on getting all of the plastic covers off the damn thing now!)

Any other hints and tips, given the diagram below, on what the problem could be - it looks like a pretty simple setup and it does appear - literally - to be the compressor stopping that's causing the problem.

Any help REALLY appreciated.

Shades

PaulC72

How long have you had it and can you not put a call in to the manufacturer and ask if they know of a common problem? it will only cost you a phone call to at least find something out.

MrShades

Had it at least 4 years or so, little used but very useful!

Manuf / importers website still exists so may try that... but I've also just registered on some AirCon forum (sad, I know - but needs must!) and one guy there said instantly that I should take it outside and hose down the 'coils' (or what I called rads).

I guess there's a thermal cutout in the compressor that is killing it, as the exhaust / compression coil isn't disipating the heat sufficiently (there was A LOT of dust/fluff build-up on it when I removed the rear cover).

At least that's my thought...

Will get my hose pipe out tomorrow unless I get any other good responses anywhere.

Shades

AndyC_772

iTrader: (2)

Sounds like a plan to me, just don't get water in the electrics!

If it runs at all then the caps should be fine - there's not a whole lot to go wrong with them tbh. At a guess I'd say the compressor is overheating and there's a thermal cutout switch built into it, so it starts running again once it's cooled down.

Give it a good clean, and if you can get at the compressor without spraying refrigerant everywhere, try oiling it.

MrShades

Well... I can confirm that it's DAMN heavy!

Just half carried half dragged it down two flights of stairs and outside for a good watering...

In the cool light of a Swindon evening I could clearly see the crap (technical term) on the 'hot' rad (that I now know is called a 'coil' in aircon engineering speak!) and with Hozelock "Metal 9-in-1" spray nozzle or whatever it's called set to stun I attacked it...

Conscious of the fact that the electrics are near the top of the unit, and "plumbing" is near the bottom - I kept the spraying and water near the bottom - but it all seemed to get pretty wet from spray (ever tried spraying water on radiator fins?). Didn't damage any fins though, other than the ones that were already hoved in (during assembly I guess)...

So - right now the sodden beast is sat in my conservatory, on a towel, drip drying. The heat in there tomorrow moring will properly dry it in a few hours and I'll see what happens around lunchtime.

Cheers all for help and comments... will report back on the final result. Hopefully it's this easy - though it still seems quite odd taking a hosepipe to an electrical air conditioner!

Shades

IWatkins

If it is of any help, I think I have the same unit but mine doesn't have the wiring diagram.

Mine also does this on very hot/humid days. But I simply unplug from mains, plug it back in and the compressor fires straight back up again.

I find the compressor drops out if the exhaust hose gets a bit too hot, so always assumed this was some kind of thermal protection.

Cheers

Ian

MikeCardiff

iTrader: (2)

I was going to suggest that - it sounds like the compressor isnt getting enough air flow around it to cool it, and is tripping the sensor. As well as cleaning any fluff out from the fins, see if there are any internal filters that can be washed out as these could be blocking the airflow.

Also, dont site the unit too close to a wall as this could stop the air moving freely around the back.

The capacitor shouldnt be an issue as they generally either work or dont.

MrShades

Get the back covers off it, take it outside and hose the 'coils' down - my lower one, the "hot" one was filthy under the covers and I managed to remove a layer of lint from the surface and then spray hosed it to get the dust out from between the fins/pipes...

Outcome is that it now seems to work properly again!

Previously the exhaust was getting pretty hot and so was the coil - but now, the exhaust air / pipe is noticeably cooler and the cold air is noticeably colder.

It appears that a regular proper clean of the rads/coils on thse (or any I guess) aircon units is required to keep the things not just working properly but working at all!

If yours is roughly the same Ian, and you're having that problem then I'd seriously recommend you doing the same as I have - it's chalk 'n' cheese...

Shades

MrShades

Added to say that whilst you can half roll / half leverage these damn things DOWN two flights of stairs, the only real way to get them back up is to pick them up and carry them. You can't use the handles as they're too high, and you can't lift it high enough to clear the next step... so one arm under the bottom and one arm to steady on top - and me and 36kgs of plastic stumbled up the stairs again.

Jeez... it's heavy and a tricky size to lift, but got there (OK, fell up the last two steps as the cat got in the way, but made a safe landing at the top with a bruise or two)

Back in situ in the bedroom and cooling it down nicely as I type!

Thanks for all help and comments again, this is one to remember...

Shades