Do we have any A/C experts here?

[Komatsu 150]

I think a lot of the propaganda on the against side might be dupont not wanting to let market share go on their patented gas.
I havent found it bad on anything as it runs at a lower pressure (only have to use a third of the amount compared to R134a ) and as far as being dangerous well no one seems to worry about the fuel tank or lpg tank under their car too much..
Anyhow Ill bugger off now and let people get back to the topic at hand. Cheers.

Oh I agree with you, I think the safety issue was way overblown. Really Freon and a flame makes a poison gas and nobody worried about that much. The commercially prepared propane blends would be better than just straight propane, I think they add a few percent of butane and other bits.

 

[OldandWorn]

Yep, NH3 Ammonia is a very good refrigerant, still used in many applications like ice making companies, it's just not very "user friendly". If you ever get a whiff of NH3, it will take your breath away. Just take care working around old refrigerators and don't knock a hole in the system, that stuff will cause immediate evacuation of the house or area.

Reminds me of when I was just out of high school working as a motorcycle mechanic. I wanted a compressor and busted an old fridge open behind the shop which happened to be sitting directly under the large building fan to keep the shop cool. I didn't know about the ammonia thing back then and it sure emptied the building out in a hurry.

 

[willie59]

Reminds me of when I was just out of high school working as a motorcycle mechanic. I wanted a compressor and busted an old fridge open behind the shop which happened to be sitting directly under the large building fan to keep the shop cool. I didn't know about the ammonia thing back then and it sure emptied the building out in a hurry.

LMAO! I bet ur eyes popped out like a stomped on bullfrog. :lmao

 

[PROBIKE101]

didyou fix it?

 

[willie59]

didyou fix it?

Supposed to get a new receiver/drier tomorrow morn so I can continue on with repairs. But I didn't order the $540 unit from Bobcat, local parts store getting a replacement for about 20 bucks.

 

[PROBIKE101]

does original bobcat reciever have a sight glass?

 

[willie59]

Yep, sight glass and binary pressure switch

 

[PROBIKE101]

binary? is that brand name?

 

[willie59]

A two pole pressure switch, sorry.

 

[PROBIKE101]

bouble pole single throw?

 

[FSERVICE]

willie is the sticker still there that has the total charge amount in #s or kg? if so get a set of electronic scales and weigh the charge. more accurate than the sight glass. and some systems are that sensitive!

 

[nextdoor]

willie is the sticker still there that has the total charge amount in #s or kg? if so get a set of electronic scales and weigh the charge. more accurate than the sight glass. and some systems are that sensitive!

It annoys me how they use stickers on gear that they should know gets pressure washed ect. Why cant they engrave or stamp it or at least use a decal that wont come off. Makes it hard when you have to work out for yourself how much gas should go in.

 

[willie59]

willie is the sticker still there that has the total charge amount in #s or kg? if so get a set of electronic scales and weigh the charge. more accurate than the sight glass. and some systems are that sensitive!

Hmm, didn't know that. But then, there's a heckuva lot I don't know about A/C.

Nope, no sticker on it to indicate required charge. I did get started on it today, then had to leave to work on a rental unit. I fitted a new receiver/drier, did a 2 hr evac, fired it up and gave it a charge until the sight glass was clear. High pressure was around 250 when I had to leave. Unit was blowing slightly cooler than it was previously.

I did check the line at expansion valve, line was warm prior to expansion valve, got cold after passing through valve. I did weigh my tank before starting to know how much it used, but day was over before I could get back to it, hope to finish up tomorrow.

 

[OldandWorn]

Nope, no sticker on it to indicate required charge.

The service manual is another place that should tell you the charge weight. It really is the most accurate way to do it. In some systems you can still get bubbles in the glass even with a full charge.

 

[rare ss]

Hmm, didn't know that. But then, there's a heckuva lot I don't know about A/C.

Nope, no sticker on it to indicate required charge. I did get started on it today, then had to leave to work on a rental unit. I fitted a new receiver/drier, did a 2 hr evac, fired it up and gave it a charge until the sight glass was clear. High pressure was around 250 when I had to leave. Unit was blowing slightly cooler than it was previously.

I did check the line at expansion valve, line was warm prior to expansion valve, got cold after passing through valve. I did weigh my tank before starting to know how much it used, but day was over before I could get back to it, hope to finish up tomorrow.

I'd be thinking there isnt enough gas in there, remember when the bubbles arent visable (on a traditional system) the receiver dryer isnt full of liquid, you need to get enough gas in there to ensure the unit is 2/3rds full in operation doing it only by measuring the gas on the way in isnt to best way to get the most out of your a/con with high ambient temps

as for LPG in a/con systems it should be banned IMO there has been afew incidents over the years with people being burnt from using this in a/con systems, most of the drive into this type of gas is from the companies selling it, afew states of Australia have banned its use in automotive a/con systems

 

[willie59]

Yep, I charged it until there were no bubbles, used 20 oz. Then after reading these posts, I called Bobcat, service man said it took 2.2 lbs, which means I needed to add an additional 12 oz.

 

[FSERVICE]

so when you added the extra did it make it work?

 

[inthedirt]

Had a machine that wouldn't cool. Had low pressure on high side and HOT! discharge line. Changed compressor and sure enough found gray sludge in system. Flushed out lines and condensor. Tried to flush evap core, but couldn't get flush to go in. I am assuming the expansion valve was closed and wouldn't let it through. Added some oil and dye after vacuuming for 1.5 hours. When I started, the high side was low (100) and low side was high (80) with only one can in it and compressor turning. After awhile all of a sudden high side went up and low side went down and I finished charging (three cans). Cooled great. After running for an hour the high side kept creeping up (ended up at 450) so I took some out and it seemed ok. Sent to customer and after a day of running high side had spiked again. let more freon out and it worked again. My question is, why is it when you start it up in the A.M. and the pressures are almost too low, but it does cool, but as the machine heats up the pressures go up and it took such little amount of freon? This is on a 140 size excavator.

 

[PROBIKE101]

ambient temperature caused head to go up, sounds like exspantin valve is stuck in 1 spot you are adjusting charge to it
not it adjusting to your charge

 

[OldandWorn]

Had a machine that wouldn't cool. Had low pressure on high side and HOT! discharge line. Changed compressor and sure enough found gray sludge in system. Flushed out lines and condensor. Tried to flush evap core, but couldn't get flush to go in. I am assuming the expansion valve was closed and wouldn't let it through. Added some oil and dye after vacuuming for 1.5 hours. When I started, the high side was low (100) and low side was high (80) with only one can in it and compressor turning. After awhile all of a sudden high side went up and low side went down and I finished charging (three cans). Cooled great. After running for an hour the high side kept creeping up (ended up at 450) so I took some out and it seemed ok. Sent to customer and after a day of running high side had spiked again. let more freon out and it worked again. My question is, why is it when you start it up in the A.M. and the pressures are almost too low, but it does cool, but as the machine heats up the pressures go up and it took such little amount of freon? This is on a 140 size excavator.

Lots of oil and more of the gray sludge was most likely in the evaporator as the evaporator is a major collection point. The only way to properly flush a system is at the component level, but yes, it can be a pain in the arse. If the gray sludge is from a bad compressor your new one might take a dump also. You missed a good opportunity for troubleshooting by not weighing in the charge.