air conditioning

[stansyerman]

My air conditioning wouldn’t come on when i started the bongo could it be frozen when i pressed the button on the heater control panel it didnt light up must have been -10 when i got in the bongo

[dom_e]

I don't think the AC works when it's too cold outside. Mine didn't this morning.

[rita]

I don't think the AC works when it's too cold outside. Mine didn't this morning.

DITTO

[missfixit70]

Why would you want the air con on at -10 ?
If you mean the fan didn't come on, it could be the motors got damp & frozen, or it's died, possibly causing problems with the control/resistor pack, this may help - http://www.igmaynard.co.uk/bongo/forum/ ... 43&t=28727

[nfn]

On other cars I've had, the AC is useful in cold weather to help quickly de-fog the windows (it sucks moisture out of the interior). The bongo's AC compressor doesn't seem to come on for long enough (or at all) in cold weather to aid de-fogging (mine has manual AC).

[mikexgough]

I raised this last winter..I asked the question as my Rad Fans didn't kick in when I pressed the button....... Dandywarhol said that his A/C won't kick in at 1C or below.....Mine needed a regas but if yours had been running it could be frozen and reluctant fans(seems unlikely) or the ambient temperature........ Mine works to -2C but not tried it any lower....I have a manual air con...and use to demist but since clearing the dreaded drain hole....I don't seem to need to run the A/C so much...but I always do the weekly run to make sure all is well....

[dave_aber]

If there is moisture in the A/C lines, then ice can form which shuts the A/C down.

[stansyerman]

Why would you want the air con on at -10 ?
If you mean the fan didn't come on, it could be the motors got damp & frozen, or it's died, possibly causing problems with the control/resistor pack, this may help - http://www.igmaynard.co.uk/bongo/forum/ ... 43&t=28727

the AC is useful in cold weather to help quickly de-fog the windows and i run mine all the time

[mikeonb4c]

I'm no expert in this but does there come a point where de-fogging become academic as the outside air is below freezing, so carries v. little water vapour, therefore will not need drying out and/or the aircon can make no useful contribution. Taking that along with dave_abers point about increased risk of freeze-blocking might give a clue as to why the system seems to do nothing (nor does it need to) in v.cold temps

[stansyerman]

rise in temp air con working again

[helen&tony]

Hi
I use aircon to defrost...never a problem...BUT the gas used in the Bongo is quite O.K. to around minus 20 or so, and is the same gas as is used in all modern domestic air conditioning systems. Last year, we had a problem with the air-con in the house, so this is how we know...we use it to heat the bedroom at night, and it wouldn't work....fearing that it was B******D, to use a technical word, we eventually got advice...leave the system on all the time, but reduce the setting to 15 or 18 during the day...we have had no problems since.
How does this equate to the Bongo?...well, you can't run the system all day, and it will freeze up ...usually below minus 15 on the car, but it won't damage the system, and you can only run on the heater alone, but as soon as the temperature rises again, give the air con a blast to keep it in working order, and keeping the seals lubricated...
Cheers
Helen

[mikeonb4c]

This page:

http://www.antarcticconnection.com/anta ... /faq.shtml

contains this item:

5. Why is the air so dry in Antarctica?

Cold air holds less moisture than temperate air. This is because the molecules of air are packed so tightly that it's as if the moisture has been squeezed out of it. This means that the air in Antarctica is very dry. Relative humidities in the interior average less one tenth of one percent! Most visitors to Antarctica pack a few extra bottles of moisturizer before setting foot on the continent!

This page (from a dehumidifier maker) was also useful:

http://www.meaco.com/guide.html#What%20 ... ing?%C2%A0

My understanding of physics, let alone my ability to put it across, is not good enough to make the case for the theory of things, but these pieces suggest (in reverse order) that (1) dehumidifying doesn't work below freezing and (2) the kind of air that is around in subzero temps after snow is already dehumidified so it doesn't matter much that dehumidifiers don't work. We needn't discuss needing aircon to cool the car - ha ha! The best thing for keeping a fog free screen will be warming the air before it blows on the screen as that will drop the relative humidity massively due to hot air being able to hold a lot more water vapour.

...at least I think so

[helen&tony]

Hi Mike

air con. in the car plus heater..demists nicely...and I use it to keep the seals good every now and then
In the house we use an air con to heat in winter
moisture in the air...well it is relating to the movement of molecules in differing stages of water...as you say, just simple physics...I'll bore you if you like
Cheers
Helen

[mikeonb4c]

Hi Mike

air con. in the car plus heater..demists nicely...and I use it to keep the seals good every now and then
In the house we use an air con to heat in winter
moisture in the air...well it is relating to the movement of molecules in differing stages of water...as you say, just simple physics...I'll bore you if you like
Cheers
Helen

Yes, if the air is warmed, or the dehumidifying principle is able to do its work, which it seems it can't below freezing. And yes, you can use adiabatic expansion and compression of aircon gas to either generate heat or cooling - no reason why one device can't do both as far as I can see.

I dont know the finer points concerning what controls the dew point or the triple point etc. but I do know that the warmer the air, the more moisture it can hold. So if you draw in cold dry air of the sort that will be about in sub zero temps and then you heat it, that air will have considerably raised ability to evaporate moisture that is fogging up a cold surface should you blow it over one. Because raising the temp. lowers the relative humidity, it is effectively demoisturised just by warming.

If that warm air - having picked up moisture from e.g. a fogged surface - is recirculated through the aircon/dehumidifier then water can be condensed out of it when it is cooled by the aircon because we are now at temps where dehumidying works.

I thinks thats how it goes but correct me if I'm wrong

[francophile1947]

It's true that you don't need the aircon in sub-zero conditions except you're forgetting one thing Mike - you breathe Breathing pumps loads of moisture into the air in your Bongo - this condenses on the cold windows (or it does in mine ).