ADVICE SOUGHT: Aircon not taking full charge - why?

[mikeonb4c]

....So I took the Bongo to a local aircon specialist as the aircon seemed to have stopped working. It hadn't been re-gassed since I bought it and had been a bit feeble for a while. They seemed to know how much gas and what type the aircon should need (850g of R134 is it?). They would test the system first for leaks and if all OK would pull out any remaining gas and refill it. Turned out it was nearly empty but they called and said no leaks but they could only get about 500g into the system. I had wondered if the pump was turning before taking it in as I got no RPM drop when I put it on. I asked garage if they'd checked the pump belt was OK and they said it was. I called Adrian just to see if the problem could be linked to my recent (Bongo) head replacement - maybe a wire had been left disconnected or some-such. He advised on a wire to check so I went to the aircon place and lifted the engine cover. Wire was in place but no pump belt- it must have failed and left the building. Red faces from mechanics, took it to Adrian for new pump belt, aircon then worked amazingly well even with only 500g in the system (should have got it done sooner!). Aircon garage want it back and will attempt the refill again, but my question is would a disconnected/non-turning aircon compressor pump have prevented the system from accepting the full charge? I can imagine it might be a bit like any system: if the fluid (liquefied gas) isn't being moved about then trapped air might prevent a full refill. If so, should the system be charged with the aircon on, so the pump is engaged and moving fluid (liquefied gas) around?

I'd welcome any thoughts on the above before the specialists resume work!

[cmm303]

Has rear aircon been bypassed, either because it wasn't working or for a conversion? This would reduce capacity.

[mikeonb4c]

Has rear aircon been bypassed, either because it wasn't working or for a conversion? This would reduce capacity.

Good thought, but no it hasn't

[Simon Jones]

So the A/C place didn't spot the compressor was missing its belt? That's pretty fundamental stuff.

[JoeC]

The system will take approximately 950g (for dual system) or 700g (front system only).

[Gasy]

I woundnt let them touch it again
If they didn't spot a missing belt

[mikeonb4c]

So the A/C place didn't spot the compressor was missing its belt? That's pretty fundamental stuff.

Indeed it is

[mikeonb4c]

I woundnt let them touch it again
If they didn't spot a missing belt

Hopefully they're embarrassed enough to get it right next time. But I suppose the non-operating compressor might be the explanation - certainly hope so!

[nth]

The A/C system is refilled with the engine switched off (therefore the compressor not turning) so it should not matter that the belt was missing, it wouldn't stop it taking a full charge. I agree though, take it elsewhere, if the missed a missing belt after directly asking the question then have they done the rest of the job right ?

[mikeonb4c]

The A/C system is refilled with the engine switched off (therefore the compressor not turning) so it should not matter that the belt was missing, it wouldn't stop it taking a full charge. I agree though, take it elsewhere, if the missed a missing belt after directly asking the question then have they done the rest of the job right ?

They've already taken my money so think I'd prefer them to see the job through. Being fair to them, they are well established and come recommended. I think they just got caught out by the unexpected - we've all had that happen before especially when very busy. The aircon is certainly ice cold even with 500g in it! I'll see if there's a factsheet in the members area I can take along with me.

[nth]

I assume they have ruled out a problem with their machine ? Maybe the scales needing calibrated or the bottle not sitting on the scales correctly ? Maybe there was only 500g left in the bottle
What are the gas pressures on the low & high pressure sides ? How long did they vaccum the system for ? Should ideally be at least 30 minutes, vacuuming boils of any moisture in the system but also helps with refilling as it mean the new gas is 'sucked' in as the system is under negative pressure.

[rita]

Hi mikeonb4c,if the compressor drive belt went missing from the time you checked it until you got to the AC specialist I would keep an eye on the compressor as they have a habit of jamming/seizing/locking and breaking/throwing the belt.

Good Luck.

[mikeonb4c]

Hi mikeonb4c,if the compressor drive belt went missing from the time you checked it until you got to the AC specialist I would keep an eye on the compressor as they have a habit of jamming/seizing/locking and breaking/throwing the belt.

Good Luck.

Thanks Rita. Not sure when it threw the belt and I agree about possible causes. Will keep an eye on it. Presumably if it does have that problem it's non repairable and I'll need to source a replacement from a scrapper?