Thread: Caravan aircon regas?

There is also a good chance it may not be low on gas,due to age,may just need a good dismantle and clean,or something else may be wrong,compresser may not be pumping properly or whatever.

The AC unit in your application is not 'automotive' as it is a fixed 240v appliance,not off engine drive.

Two completely different applications.

R22 is the best refrigerant as it was designed for it.

If it is low the leak will need to be repaired before it is recharged.

There is that much r22 around,you should be able to find someone local at a good price.

If not R407c is the next option,but an oil additive must be added as well,as the compressor, more than likely is operating on mineral oil.

How long does it take ?

Recover original charge (what's left), evacuate and try and pull sub 400 micron vacuum, charge with new refrigerant while checking superheat plus air off temps to get the new charge right, and put it all back together, yep, it can take that easily.

It can be faster, it can take longer too, so many variables including system size.
Eg. one of our young techs did two 16 hour days and then a little more trying to get a chiller back up and running last week after a solenoid valve cracked, but that system takes 180kg of R134a.
A smaller 80kw chiller took me several days too, but I left the vac pump on for two days as I was struggling to get a decent vacuum, couldn't get under 1200 microns.
Bloody vacstat sensor was contaminated with oil.

FWIW I found MO99/R438a a really good drop in for R22, it works nicely in heat pumps.

Originally Posted by Pedro_The_Swift

I really cant see an issue with flammability,,
with a gas stove we already have that inside the van,, and all vans are built to "drain" any gas out the step,, check your door for louvers,,
just watched a vid of some guying re-gassing a system using MO99 and it took him 2 and a half hours!
is that amount of time normal Rick?

That's what I said... Bang gas in a coolroom scares the **** out of me ( as it's a sealed, air tight room evap side). But a caravan is designed to vent any gas that is heavier than air.

Originally Posted by Pedro_The_Swift

Just found some more paperwork,, it seems mine is a "boosted" Wren,, 3.5kw's, designed by aircommand for trucks buses, road machinery etc, 12K btu's
Suck on that Ibis3!

Pedro me lad. Why didn't you post this before my brick came with Ibis 3 - which is marginal at best on a hot day for a 20 foot plus "insulated" caravan.

Hychill minus 40 is high purity propane. Nothing too flash.
Same calculations would work for 'ballpark' LPG- LPG is mostly propane, with some butane added.

The lower explosive limit (LEL) of propane is 2.2%, Upper explosive limit (UEL) is ~9.5% (in air). In this range, you get an explosion.
1M3 of propane (gas state) weighs in at 1.898kg.
It's density is 1.55 times heavier than air (1.898kg/m3 propane, vs 1.225kg/m3 for air, at 1bar, 15C).

Assuming a big caravan, say, 24m3 (2m x 2m x 6m- empty shell- disregarding any volume of furniture, cabinets, etc), you'd need approx 0.53m3 of propane to reach the Lower explosive limit. This relates to approx 900g propane to go bang.

Reduce the size of the caravan to something more modest, add furniture that displaces air, add sources of ignition, and things can go pear shaped. Doubly so if HVAC equipment and/or ignition sources are in a cabinet or other inclosed space.

Would a pressed metal vent in caravan door be sufficient to vent a suitable mass of propane before it diffuses around the space to reach the LEL? I don't know. But would I mitigate the risk if I have a choice? Heck yess.

Moving from a caravan to a vehicle- an engine bay with points ignition, hot surfaces and a lower M3 volume of available space would not require much of a propane leak to cause a problem.
As another example, your coolroom (lets assume a little 8m3 -2x2x2m- trailer mounted coolroom) would require as little as 330g propane to go bang.

Thanks Toxy,,
I'm wondering on the amounts of "sudden leaks" in vans,, mine has lasted 26 years,,
and it has to be a ^^ for an aircon to be a concern..
any slow leaks during the day time will be sussed pretty quick,, we had a leak from a bottle in the front and you can smell them easily if it happens,,
there aren't that many points of ignition in a van, even during the day! and during the day the door is opened regularly,,


all this pales into insignificance as we've had a underbonnet LPG hose split and we heard and smelt it at the same time, and abandoned ship REALLY quickly!!!

I'm extra cautious, as I had a car aircon degass itself catastrophically once. Funnily enough it was as I was pulling into a mechanic to get a quote for some other work.
Hot day, low 40's, a heat-soaked system, and a short drive as it was trying to cool was enough for the condensor to let go. TThere was that much smoke that I'd thought a radiator hose had let go, as smoke/steam was billowing out from the bonnet. The mechanic and I had a bit of a chuckle about how good the timing was, and we moved on with repair. It could have very well been a very different story if it was a flammable refrigerant.

Smoke?
aircon gas released=smoke

???