Refrigerant recovery from a HVAC system has been mandatory since 1995 when the EPA enacted the Montreal Protocol and required 608 certification of all technicians. refrigerant must be recovered otherwise huge fines can be imposed.
The EPA does allow for de-minimis release, or basically refrigerant released when connecting hoses to and from a unit or tank.
What Will Be Needed
HVAC gauges to connect hoses between a HVAC system, recovery machine, and recovery tank.
Recovery tank, tanks with a yellow top are designated Recovery Tanks.
1…The gauges should be turned off and then connected to the high and low sides of the unit to be recovered from. Red goes to the high side, Blue goes to the low side.
2…The center yellow hose goes to the suction line of the recover machine marked IN, a dryer should be placed here to help keep contaminants out.
3…A single hose than goes OUT of the recovery machine to the recovery tank.
4…Set the recover tank on a scale to measure how much refrigerant is removed from the unit, and ovoid overfilling the recovery tank. By law a tank can only be filled to 80 percent capacity.
5…After everything is connected we need to purge the air from the hoses. This is done by opening all the valves from the unit to the tank, only the tank valve should be off, than at the tank letting the air push out of the hoses. This will only be done for a few seconds. At the tank unscrew the hose slightly until air is heard escaping, after a second or two re-tighten the connection to the tank. The refrigerant will be under pressure and push the air out of the lines.
Pressure at the recovery machine will show when all valves are open
Purging the lines
6…After the the lines are purged we are ready to turn on the recovery machine. The recovery tank valve along with all other valves should be open, than the recovery machine can be turned on.
7…At the HVAC gauges and recovery machine you should see the pressure begin to drop as the refrigerant goes into he recovery tank. Be sure to watch the scale as to not overfill the recovery tank, a tank should never be filled pass 80 percent of its capacity. The recovery machine should be working up to it reaches 0 psi on the low side of the recovery machine. Don’t go below 0 psi as if there is a leak you will be sucking air. Most new recovery machines will turn themselves off automatically when they reach 0 psi.
8…After the recovery machine has reached zero psi and shut off the recover machine needs to be purged. To do this turn the low side blue valve to purge and the high red side to purge on the revery machine. Then watch the gauges on the recovery machine. The low side will go from high to low and the recovery machine should shut down when its done.
9…Close all the valves, especially the recovery tank, and you are done.
There is more that can be done to speed up the precess of recovery such as turning on the blower motor so the liquid doesn’t freeze, getting quicker recovery times.
Refrigerants should never be mixed R-22,R134, R-410 should all be kept separate. Old refrigerant shouldn’t be mixed if the refrigerant is going back into the system it was removed from.