Those things hit the wall a few years ago when they stopped using copeland comp.
Well, the one i worked on yesterday had a techumseh. I don't think this was ever worked on it's entire life and to my dismay the suction stub on the compressor was kinked. Can't they do a better job piping. And the braze joints are just average. I expect pro welds!
just weigh in charge after vac ,pure liq. on discharge side and let it set for a few min.best is to precharge ur hoses br haveing a yellow jacket shutoff valve at end of hose then read scales till full weight is in, never failed me.
0.90 ounces is about 25 grams - so if you use a gram scale graduated to tenths it would seem easy to be accurate. It's not going to be all That critical anyway. You could charge it by SSH at stabilized conditions and it would be close enough. I guess it would pay to use shutoff valve hoses though. <g> The factory probably weighs the whole unit on a gram scale as they install the charge. No one could afford to have these serviced for what a new one costs anyway.
Have you ever looked at the refrigeration system in these bottled water coolers? Don't worry about charging them. You will never have to do it. Unless there is a bad switch or thermostat, any other problems you throw them out.
Didn't you come up with some elaborate scheme to weigh in charges this small before?
Buy a medical grade diaper scale, or steal one from your local NICU. That's what drug dealers seem to use. Their measurements are a lot more critical than ours.
Take a ball valve hose connected directly to the refrigerant tank, ball valve end towards unit. Purge hose, charge unit by weight, close ball valve and you're done. Tare the scale when the hose is purged and full, of course.
If it costs the customer less for you to repair that thing than it does to replace it, you need to increase your labor rate
But have been successful with putting a stubby hose with ball valve on the condenser, purging to the ball valve with vapor, then opening the ball valve to control charge. That way there is little to know compensation for hoses. Use a mechanical scale (Shipping type scale) if you require extreme accuracy. I had a "Coffee Creamer Cooler" at a C-Store that had .34 lbs R-134a. Wasn't easy. Then found out They just replace them... cost more to repair than buy. Looking at the water cooler you are working on, can't be more than a couple hundred bucks. Buy the time you fix it, you'd have more in it than a new one would cost.
I'd like to find these.....
There's no such thing as normal...
Just different kinds of crazy...
Wholesalers here sell a tiny scale, designed for the 1lb R600a etc cans. It has its own hose which is the very thin plastic pressure switch style with a bore of a few mm. Lots of domestic stuff here runs R600a or R290 and only has a few grams in.