HOW TO ADD
MAKE IT A PRACTICE TO WEIGH THE SERVICE CYLINDER BEFORE AND AFTER ADDING REFRIGERANT. THIS
IS THE ONLY WAY TO TELL HOW MUCH REFRIGERANT HAS BEEN ADDED. Inasmuch as the original loss of
refrigerant may have resulted in a loss of oil at the same time, check up on the compressor oil supply after several hours.
Be sure the lowside suction valve is turned all the way to the left to close the guage port. Install a tee connection. Put the
compound gauge on one end, and connect the far end of this tubing to pound the refrigerant cyclinder. Before tightening
the connection finally, crack the service valve to purge the air in the regular way. Attach the pressure gauge to the
Warm the refrigerant service cylinder by putting it into a pail of warm water, or by using hot cloths. DO NOT USE A
BLOW TORCH. Place the cylinder in an upright position with the valve at the top to admit refrigerant vapor, and not liquid
to the compressor crankcase.
Now turn the lowside valve inward, so that the compressor crankcase is opened to the compound gauge and to the tubing
which leads to the cylinder for fresh refrigerant. Start the compressor; watch the compound gauge, then open the valve
on the service cylinder.
Whenever the compound gauge drops below 28 lbs. open the cylinder valve, whenever this gauge reads about 29 lbs.
close the cylinder valve. AIM to keep the compound gauge steady at approximately 28-29 lbs. Don't admit too much
refrigerant or admit it rapidly enough to permit the compressor to knock.
Continue to admit the refrigerant vapor in this matter until the compound gauge reads constant between 28-29 lbs., and
the pressure gauge shows a reading that corresponds to the room temperature.
Next, close the valve on the service cylinder; let the unit operate long enough to take in the remaining gas from the tube
into the compressor; turn the lowside service valve all the way to the left, stop the compressor and remove the service
cylinder. Run the machine about 15 minutes and watch the pressure on the highside. If the pressure is too high,
indicating that too much refrigerant has been added, crack the connection at pressure gauge and release enough to get
correct reading. Then remove the pressure gauge and look over every connection for possible leaks. (For correct head
pressure, see name plate. If the room temperature is slightly higher, the pressure will increase slightly and vise versa).