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Using Propane in Volvo AC

casioqv said:
Dave- what are you using to draw the vacuum? I have one of those $15 harbor freight venturi pumps, but it doesn't seem to work very well.
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I have the same thing. It pulls 25 inches using my 6 hp compressor (6.4 cu ft @ 90). Anything over 10 or 15 inches should do ok. Just might need to pull longer if you can't get a lot of vacuum.

Also, when I first begin pulling vacuum, I shut down the high side and low alternately a couple times just to move any moisture there might be in the furthest recesses. Then I let it suck for 20 to 30 minutes.

BTW, still rainy here.
Dave
 
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vlvman said:
I use a Robinair 5 cfm vacuum pump. On an unfamiliar system, or on a system I have had open, I let it suck for at least 45 minutes
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So if you're going to get serious about DIY AC repair, it sounds like spending a few hundred $ on a powerful pump should be in the plans.
 
You are mainly using a vacuum to lower the pressure so water/moisture will turn to a vapor/gas and can be sucked out as it does so. This is for large amounts of water trapped in the dryer, hoses, coils and should be done for a fair amount of time, 30-60 mins or more. The warmer the ambient the better, the water basically boils out under a lower pressure more quickly just as it does sitting on a table, just quicker. Sucking out the existing gas/air/water vapor in the system is secondary as a quick purge will do this and should be done anyway. If you do not install a new dryer then you can heat it up a bit with a heat gun still in the system, do not melt the seals, during this process and remove some of the stored water from the desiccant as well. A new dryer and an oil change is the smarter choice for bringing it back to original condition. If the system was recently charged and has a new dryer and you are just changing out refrigerants it will not have much moisture in it anyway. An old system that is full of "goo" will require a flush if you are trying to clean it out.


Robinair is a good name and have been around for decades, vacuum pumps last forever if not abused, I have seen them thirty + years old and working fine with some maintenance, so a good used one is fine also, try Craigslist and save on shipping and see it first hand to check it with a gauge before you buy:


http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=200365157804&ssPageName=STRK:MEWAX:IT
 
Got mine new off fleabay for about $200, five years ago. I also tend to buy freon in 30# jugs, I have 30# of R22, part of a 30# R134a, and 12 oz. of R12. I have one set of Richie gauges I use with pag, poe oil systems, and another set I use for mineral oil based systems.
Winter is the best time to buy freon. I get it locally at the refrigeration and appliance parts supply.
 
"It's quite a dichotomy: Convert your car to run on Propane and you are lauded for being "green." Put in your a/c and you are told that you have a rolling bomb--what a f*cking joke. Last time I checked, there was no oxygen in a properly evacuated a/c system--and only 2/3 of a pound of refrigerant. Yea, I'd rather have 20 gallons of fuel in my trunk and choke on phosgene gas! Idiots."
 
Phosgene gas should not be an issue until at least 3 ppm so don't worry about.


CONCLUSION: Phosgene exposure is associated with significant morbidity and mortality. Physicians should be aware of the risk of phosgene exposure when heat is applied to Freon, commonly used in a variety of industries. Patients with a history of exposure should be admitted to the hospital for observation given the potential for delayed onset of respiratory failure and ARDS.


http://meeting.chestpubs.org/cgi/content/abstract/136/4/9S-c
 
Thanks. I wonder how much difference - if any - there is in a 134 system?

I swapped in an entire 93 airbox/AC system into my 88 245 so I have to figure out how much "stuff" to order. :-D
 
15A said:
Thanks. I wonder how much difference - if any - there is in a 134 system?

I swapped in an entire 93 airbox/AC system into my 88 245 so I have to figure out how much "stuff" to order. :-D
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I listed the capacities for 240s from '79 to '93 in the first post.
Dave
 
dbarton said:
Is there NO ONE in here who will admit they have (hypothetically) tried propane?
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*I* have. Product called Duracool. I've used it for years. I'm not going to bicker with people about the "oh noes" about it. I can say this. It works, it works very well. On the hottest days last year I would routinely get 34?f out the vents. I use around 18oz. of Duracool versus 30 or so ounces of R12. The system doesn't work as hard either. Propane has a higher flash point than r134 & is more environmentally friendly. It's safe for the existing seals & is completely compatible with my old R12 system.

I am the only one who services my A/C so I'm not worried about sniffers or anything. If I want to purge the system, I've connected a catch can & plumbed it inline to a vac source on my intake.

I'm nearly 100% confident using it. I've had zero issues & I'm really not worried about a rupture causing a fire as 18oz. really isn't that much, I doubt it'd blow up the car.
 
Ursan said:
*I* have. Product called Duracool. I've used it for years. I'm not going to bicker with people about the "oh noes" about it. I can say this. It works, it works very well. On the hottest days last year I would routinely get 34?f out the vents. I use around 18oz. of Duracool versus 30 or so ounces of R12. The system doesn't work as hard either. Propane has a higher flash point than r134 & is more environmentally friendly. It's safe for the existing seals & is completely compatible with my old R12 system.

I am the only one who services my A/C so I'm not worried about sniffers or anything. If I want to purge the system, I've connected a catch can & plumbed it inline to a vac source on my intake.

I'm nearly 100% confident using it. I've had zero issues & I'm really not worried about a rupture causing a fire as 18oz. really isn't that much, I doubt it'd blow up the car.
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Is this a Volvo 240 you are talking about when you mentioned the charge size of Duracool-propane, good info to know?

The reason it will not blow up or kill you, although a very remote chance of minor burns, is the mixture of propane needs to be between 5-15% propane to air. Of the mixture only the gas very close to you will burn, 6" away from a 75,000 Btu barbecue burner and your skin is fine, so that amount of gas is even more ridiculous to kill you. There is a video done at a university that I have been looking for and the typical amount of propane gas in a refrigerant charge was ignited and nothing blew up, just a good poof.

Look at the bright side if we did not have Freon where would we get our home made nerve gas from?
 
moxy123 said:
Is this a Volvo 240 you are talking about when you mentioned the charge size of Duracool-propane, good info to know?

The reason it will not blow up or kill you, although a very remote chance of minor burns, is the mixture of propane needs to be between 5-15% propane to air. Of the mixture only the gas very close to you will burn, 6" away from a 75,000 Btu barbecue burner and your skin is fine, so that amount of gas is even more ridiculous to kill you. There is a video done at a university that I have been looking for and the typical amount of propane gas in a refrigerant charge was ignited and nothing blew up, just a good poof.

Look at the bright side if we did not have Freon where would we get our home made nerve gas from?
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When I used it in my 240 (1983) I used roughly 2/3 what the system called for. I'm currently using it in my 780. I'd originally been converted to run R134. My AC would run constantly & struggle at it.

I had the system purged, pulled a vac for 14 or 16 hours or something and loaded it with a little more than 3 cans worth. (20-22 ounces) total. I followed it up a can of Duracool SystemSeal and DuraDry.

No issues.
 
Propane update:
Finally a good warm day. Ambient between 87 and 92F mid-day. Tested for approx 1.5 hours on streets and freeway.

Short version: Ran great!

Prior to testing, I added some propane, 3 oz, bringing total charge up to about 8 oz.

Details: With 'recirculate' button in normal position and AC set at between 3 and 4 o'clock, vent temps were 47 to 42 degrees (colder on the freeway of course). Inside car temp was a steady 75 (this is a black car BTW).

With 'recirc' button depressed, AC setting not changed, vent temps were 38 to 35F (coldest on freeway). Inside car temp reduced to 72.

I think it would get pretty chilly in there if I tried a high AC setting. All in good time though. Hotter climate yet to come. I think this is going to work pretty well.
Dave
 
dbarton,

Keep posting the results when it gets hotter outside. I am curious to the performance in the 100 F range ambient, remember the humidity level too if you can. High and low side pressures would be nice too, just in theory of course. Is the evap frosting up as well?

As Ursan mentioned the quantity of Propane/Propane mix seems to be about 0.40 times the original Freon charge quantity that I have found.
 
Dave, thanks for the updates. I'm encouraged to see that the 240 system responds well to propane, and hopefully other HC deriviates.

I'll post up my results whey I get my system running. It's the car in my sig, converting from the old '78 on/off only AC to 80's style thermostat. It has the rotary compressor as well. Just replaced the blower, waiting on the receiver and expansion valve to put it together, then putting Enviro-Safe in. I already have ES in my Jeep and it's worked perfectly for the past two years.

BTW, does anyone know if the 81-up blower light tube (held in by the blower speed switch) will fit an -80 dash? Just wanted one that has 1-2-3-4 instead of 1-2-3, but I can live with it if it doesn't. Thanks.
 
moxy123 said:
dbarton,

Keep posting the results when it gets hotter outside. I am curious to the performance in the 100 F range ambient, remember the humidity level too if you can. High and low side pressures would be nice too, just in theory of course. Is the evap frosting up as well?

As Ursan mentioned the quantity of Propane/Propane mix seems to be about 0.40 times the original Freon charge quantity that I have found.
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I haven't been under the dash this week. I will assume things are the same as reported last week, slight frost accumulation on the expansion valve.

Today was about 85F. Humidity was about 46%. AC still running great, same vent temps.
 
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