Recovery Cylinders

Hey guys. I'm doing an automotive course at the moment. We have touched on safely filling and not overfilling recovery cylinders when pulling refridgerant out of vehicles.

Here's what was taught: Each cylinder is stamped with a tare weight in KG, and a WC (water capacity) in litres. 1 litre of water = 1kg (roughly, depending on temperature of course).

The cylinder should be filled to maximum 80% liquid level to maintain the 20% vapour safety margin.

So 80% of WC + TW = maximum cylinder weight. Eg. If WC is 22, and TW is 13: (0.8x22)+13 = 30.6kg max weight.

To me that all sounds good and well if you were filling it with water, but am I right in saying liquid refridgerant weighs less than water (in our case R134A), so therefor to put 22L of R134A in would fill the liquid level to 100%, although it would weigh less than 22kg.

So you could continue filling the example cylinder, thinking more will fit until you reach 30.6kg. But you would end up having it 100% full before you got to 30.6kg.

This seems wrong to me but everyone insists it is right. It's even in the documents we have been given.

Does the WC already include a 20% margin? Is there something else I'm not understanding?

Thanks

submitted by /u/pman92
[link] [comments]