Hagen Brothers farms,Goodrich ND | redgreenandrust - 7/22/2012 15:32
Not really sure what happened other than the guy showed me a can of what he put in before switching over to 134a. He must have put the conversion fittings on after putting in the glider gas. It was not cooling and showed a low charge so I put in a couple cans in through the manifold gauges. Pressures were coming up and I picked up the can by the fitting on the top to feel how much was left in it when I heard the loudest bang i ever heard in my life. The bottom of the can blew out and put a hole in the bumper cover, the valve on the can tap tore open the palm of my hand just behind the first knuckle and chipped a piece of bone off and then tore upward in a spin and put a dent in a sheet of roofing steel in my shop. I assume there was some air in the system and it somehow combusted with the propane or else it was somehow a rapid chemical reaction, but nothing is for sure. After bandaging my hand I got a new pair of shorts and took the rest of the day off. I also refused to work on that vehicle again. Ever.
Trying to imagine what was going on to backfeed high pressure into the little 12oz can. Did the guy install the 134a conversion fittings on the wrong R12 port so the big low side R134a adapter was on the high side R12 port of the compressor ? Could the high side valve on the gauge set have been cracked open or leaking, to put high pressure refrigerant back into the can ?
The can tapper valve is supposed to have a check valve to prevent backflow into the can, but they don't always work.
Back in the day when R12 was still common, I tried adding refrigerant into an unfamiliar system. I got things running and cracked the low side gauge set valve open to let refrigerant (R12) into the system. I was just lucky that I still had the little can in my hand, as the instant I opened the low side valve, the can started to get warm !! I thought " what is going on here" and closed the low side gauge valve . I looked over the hose connections, then realized that I had the hoses connected backwards on the identical R12 low / high fittings!!!!.
When i cracked the low side valve open, I was feeding high pressure refrigerant back to the can !!!
I was really lucky that I noticed the temp increase of the can and closed the valve before high side pressure exploded the can in my hand / face.
The check valve in the can tapper valve should have closed and prevented any refrigerant flow back into the can, but it did not, so I had no protection from my own wrong connection screw up.
I will never forget that one (20 years ago), just really glad I got away without doing a lot of damage to myself. |
R134A phase out
