Dash Air How Much Does an R-12 System Holds

[2dogs]

Does anyone know how much r-12 the system holds?
thanx, Brian




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[encantotom]

mine was converted to r134a and has a label on how much it holds. i am enroute home from singapore and when i get home i will read the label and post it.

tom

[fulltiming]

Mine was converted to R134a also. The label shows 4 pounds of refrigerant and I believe 10 oz of lubricant but the lubricant amount is extremely hard to read and may not be correct.

[2dogs]

Michael, When converting to 134 did you have to change your hoses? or just the o-rings and fittings?

[fulltiming]

The conversion was done by the previous owner. They only changed the o-rings and fittings. However, I will say they did a lousy job and the system will not hold a charge for more than a couple of weeks now. Newell asked if I wanted it fixed but at this time, with the volume of air that the dash blowers put out, I decided to stay with running the genset and using the basement airs to keep the entire coach cool for the wife and dog.

[tuga]

Mike,

I never could keep my dash AC cooling in my '87 and '93 Newells. I had freon added numerous times, compressor changed, and it still would only work a short period of time and then start blowing hot air again. I finally gave up!

My '99 Newell has a different dash AC which is housed in the generator blower bay (1st bay on passenger side) and it will freeze you out! It can keep the entire front part of the coach very comfortable during 80 degrees outside. We don't even have to run the generator for the basement ACs.

Brian,

I don't know what vintage your Newell is, but when I replaced the dash AC compressor on my '99 last summer Newell told me that it took exactly 4 pounds. We put in exactly 4 pounds and it worked perfectly ever since.

[encantotom]

i got home last nite after midnite after getting delayed in chicago....i just checked and mine says 5 pounds of r134a and 8 oz of oil.

last summer before a big trip i put freon in mine until it worked good at the dash and it took alot of freon. it lasted the two week trip then died off, and doesnt put out a ton of air, just like the others mentioned above.

i will top it off before my trip coming up, but only expect it to last the first few weeks of the trip.

tom

[chockwald]

I just had the compressor and dryer replaced on my dash A/C. Apparently the compressor on mine was a Chrysler A/C compressor. While the air volume is not great it does the job, and am I ever glad I had it this week, as the entire western U.S. is under a high pressure ridge, and temps pretty much every where are at, or exceeding 100. Was in Zion two days ago and it was 106. Am just south of Salt Lake City and it is finally dropped to 94! Hope with the new dryer and compressor that mine will hold a charge more than 2 weeks!! I'll let you know.

One recurring problem I have is sometimes when I turn the fan off, then the engine, the fan will not come back on when I restart the engine. Typically, once I turn on the ignition I will hear the dryer fan come on. If it doesn't come on, neither will the A/C fan. I have to tap the relay under the dash board so it will reset. Now, since the last time it happened, I have turned the ignition, and engine off first, then turned off the fan, and so far it has come back on every time. Mine A/C fan runs with the ignition off, and the engine off...is this normal?

At any rate, if anyone else has experience this issue, or has some trouble shooting suggestions, let me know.

[fulltiming]

Clarke, I do not think that the dash A/C fan running with the ignition off is normal. Mine is connected through the ignition switch and will ONLY come on if the ignition is in the on position.

[encantotom]

i had my ac serviced today. when they got enough freon in it (mine was converted to 134a), the compressor knocked and the temp only got down to 60 degrees.

so i am having a new compressor and complete system serviced and flushed etc. new dryer and expansion valve.

they assured me it would be cold again. so i will see tomorrow.

tom

[encantotom]

picked up the coach today after getting a complete new AC compressor, clutch, expansion valve and dryer. they flushed out the system, pressurized it with nitrogen and found a leak, repaired it and filled her up. blows 38 degree air now. like the rest of you, it is not a huge air flow, but enough to chill it down some up front. i drove it home when it was 112 degrees today with only the dash air and i didnt pass out...

what my compressor was doing was that when you put enough freon in it, the compressor worked hard enough it started making a knocking noise. ended up it was the bearings. the mechanic showed the old compressor and sure enough the bearings were bad.

so, we will see.

later

tom

[Richard and Rhonda]

If you poke around the site, you will see an earlier post by me, where I talked about my own experiences with the Dash A/C.

As part of subsequent follow ups, I ended up evacuating my system again to check the expansion valve. As some of you have found out obtaining accurate charge information and lubricant capacity is a ambiguous journey. Gas charge is easy enough to check with your gauges, but how the heck do you know how much lubricant is the right amount. Evans Tempcon and STS Frigette recommend that you charge the system, run the AC for a while, then empty the system, and check the amount of residual lubricant in the compressor. Right. Who is going to do that? Well, because I took the system down again, I did. I am glad I did. Even though I put 8 oz of lubricant in when I first installed the new compressor, I DID not have the recommended amount left in the compressor when I went through the process above. Sanden recommends that you have about 3to 4 oz residual in the compressor. Until I started reading these recent posts I didn't connect the dots. Hmmmmmmm, my compressor bearings failed, at least two other reports of compressors knocking. My guess is that in general we don't have enough lubricant in our AC systems. A lot of the lubricant is hung up in the long hose runs to the front.

So.......the moral of the story is this. Next time your system leaks down, take the compressor off and check the lubricant level before you gas it up again.

The seond thing to keep an eye on is the belts that drive the compressor. I had to tighten mine twice after new ones were installed. They do stretch a little.

[Richard and Rhonda]

If you poke around the site, you will see an earlier post by me, where I talked about my own experiences with the Dash A/C.

As part of subsequent follow ups, I ended up evacuating my system again to check the expansion valve. As some of you have found out obtaining accurate charge information and lubricant capacity is an ambiguous journey. Gas charge is easy enough to check with your gauges, but how the heck do you know how much lubricant is the right amount. Evans Tempcon and STS Frigette recommend that you charge the system, run the AC for a while, then empty the system, and check the amount of residual lubricant in the compressor. Right. Who is going to do that? Well, because I took the system down again, I did. I am glad I did. Even though I put 8 oz of lubricant in when I first installed the new compressor, I did NOT have the recommended amount left in the compressor when I went through the process above. Sanden recommends that you have about 3to 4 oz residual in the compressor. Until I started reading these recent posts I didn't connect the dots. Hmmmmmmm, my compressor bearings failed, at least two other reports of compressors knocking. My guess is that in general we don't have enough lubricant in our AC systems. A lot of the lubricant is hung up in the long hose runs to the front.

So.......the moral of the story is this. Next time your system leaks down, take the compressor off and check the lubricant level before you gas it up again.

The seond thing to keep an eye on is the belts that drive the compressor. I had to tighten mine twice after new ones were installed. They do stretch a little.

[2dogs]

Richard, How did you check the expansion valve? on ours the high pressure side keeps dropping and the low side drops into a vacuum when running they blew through the system and there was little resistance confused.......Brian

[Richard and Rhonda]

Let me consult one of my AC books to see what they say is likely to cause what you are describing, which if I intepret correctly high side dropping with time, and also low side dropping with time. Do you have any idea what your starting pressures are, what they decay to, and how long that takes. Also what was the ambient temp when you took the readings.

What else is going on? Does it start out blowing cool air and then stop? If you put your hands on the expansion valve, does the outlet feel cold?

I am not sure what you are describing is an expansion valve problem. Here's why. If the valve were not restricting flow as it should then the low side would be higher than normal and the high side would be lower than normal. That is not what you are describing. In my way of thinking you are describing is a low charge. For example, it probably takes a good 4 or 5 minutes of running my AC for the low side pressure to drop to it's equilibrium point. It starts out around 40 lbs and gradually drops to 20 and stabilizes. In your case if the low side is in vacuum, then obviously there is nothing for the compressor to compress, so naturally the high side will not have a high pressure.

Does your system have a low pressure cut out switch? This switch is usually mounted on the low side just shy of the compressor inlet. It's purpose is to keep the compressor from running if the gas is too low. Running the compressor without gas burns it up. This switch will turn interrupt the power to the compressor clutch. Is your compressor actually turning when you see this? Obviously the pulley turns all the time the engine is turning, but is the center bolt turning? You have to look at that to see if the compressor is turning.

As far your specific question, I had higher than normal high side and lower than normal low side, so I figured the expansion valve could be partially occluded from fragments generated when my compressor cratered. So basically I was looking for physical evidence of a clot. Mine did have a little crud in it.

They are relatively cheap, it's the recharge and labor that gets you. You will find that one trip to an AC guy will pay for a decent set of gauges, a handbook, and a 30 lb tank of 134a at Sam's.

I'll PM you with my cell if I can.

[Richard and Rhonda]

Hey Brian,

Have you had a chance to look at your system? We would love to know what you have found.

[chockwald]

Well, two weeks later my dash A/C is still blowing icicles. We were so grateful to have the dash A/C running. We had to add in the roof A/C half way to Vegas (was like 110+ degrees in the desert), and finally shut it off in St. George, UT when it cooled into the 90's in the early evening. Didn't have to run the roof A/C again the rest of the trip.

Going to have my mechanice figure out why the panel A/C fans continue to run after the ignition is turned off. I must manually turn the switch to the "off" position, or they continue to run. Small issue, but irritating nonetheless.

[2dogs]

Sorry I haven't been able to get back to the AC issue, my wife has had me putting down laminate flooring in the coach in preparation for our winter down south, lots of time and work involved. Didn't take a before picture but the results are fantastic. Back to the AC... had 4 lbs R-12 put in, brought the pressure up so the high and low side almost equalized, started the coach and turned on the AC then the high side dropped and then the low side went into a vacuum, we turned off the AC and it stayed at a vacuum state. They said that the expansion valve may be clogged, but when you induce air from the low side at the evaporator there is slight resistance throughout the whole system, hence no blockage. If air passes through, why not freon? Must go south to find an AC specialist, no one in North Idaho really knows what air conditioning is, a heater is more important. Does anyone know of a good AC place between here and Yuma, we will be heading down in September.

Thanks a lot, Brian

[Richard and Rhonda]

Brian,

If the expansion valve is blocked, the high side will go even higher and the low side will go into vacuum.

When you shut it down, the pressures take a while to equalize again. That is normal. Maybe up to 30 minutes.

Just because you have pressure on both low and high gauges with the compressor off tells you NOTHING about how MUCH gas is in the system.

Was the system leak tested prior to putting gas in it? The 4 lbs of gas could have gone out as quickly as it went in. After all, the original R-12 went somewhere !!!! I wouldn't do anything else without a leak test first.

[2dogs]

well it seems i said it wrong. the high side does go up and the low goes into vacuum so i guess my question is where is the expansion valve and is it easy to change?
Brian