Do High Low Temperature Chamber need refrigerant?

Prepare a scale and weigh the refrigerant cylinder, recording the total weight and the net weight of the refrigerant.

Place the cylinder on the scale with the threaded end connected to the cylinder and the other end connected to the multi-purpose port of the compressor suction valve. Do not tighten the nut on the multi-purpose port initially. Open the cylinder valve slightly and then close it to expel the air from the connecting pipe, and then tighten the nut.

The refrigerant is charged in the form of a wet vapor, so when opening the cylinder valve, it should be done carefully to prevent liquid slugging in the compressor. At the same time, open the multi-purpose port of the compressor suction valve to start charging the refrigerant. If the refrigeration system of the high and low temperature test chamber is under vacuum, the refrigerant from the cylinder will automatically flow in until the pressure balances with the cylinder pressure, at which point the refrigerant will stop entering. If the system still needs more refrigerant, close the cylinder valve, the outlet valve of the receiver, the manual expansion valve, and the suction valve of the compressor. Start the cooling water pump of the condenser and then start the compressor. To prevent liquid slugging, slowly open the suction valve to draw all the refrigerant in the system into the receiver, creating a vacuum in the low-pressure part of the system again. Then open the cylinder valve to allow the refrigerant to automatically flow into the system.

Repeat this process until the required amount of refrigerant is added to the high and low temperature test chamber. Alternatively, after the system is evacuated again, open the outlet valve of the receiver and slightly open the expansion valve to let the system run normally. Then open the cylinder valve and gradually close the suction valve (i.e., open the multi-purpose port) to allow the refrigerant from the cylinder to flow into the system due to the pressure difference between the bottle and the suction pressure (be careful not to cause liquid slugging). When the required amount is reached, close the cylinder valve, let the residual refrigerant in the connecting pipe be drawn into the system as much as possible, then close the multi-purpose port, stop the compressor, and the refrigerant charging work is basically completed.