How to Convert From R-22 to R-410a

Make sure that all power to the air-conditioning system is off. Generally, it will have its own dual circuit in the box, but if the box isn't labeled, turn the system on and test with different switches to see which one controls it. Then turn that switch off.

Have a certified technician remove the R-22 refrigerant from your system. You must have EPA licensing (Section 608 Type II or Universal) to handle or remove the refrigerant.

Use a screwdriver to take off the screws connecting the ductwork to the blower unit. If you didn't already turn off power to the evaporator, do so now. Pull the evaporator out after you've gently slid it away from the ductwork.

Disconnect the liquid and suction lines running from the condenser and take out the mounting screws. Then, you can pick up the condenser and remove it.

Use the flush kit to clean out the copper line and then run nitrogen through the line to get all contaminants and old coolant out of the system. Then repeat this step (you'll need two kits) to ensure that the line will be just as clean as the new parts you are installing.

Set the R-410a-compatible condenser where the old condenser was and replace the mounting screws. Wipe off the liquid and suction ports with a cloth. Apply some flux to the ports and any new pipes. Use the silver solder to secure the fittings once the tubes are in the fittings. Then, connect the pipework to the evaporator. You may need to add different fittings or other pieces.

Put the R-410a-compatible coil inside the evaporator. Clean any ports and connect the coil to the system. Use the silver solder on all joints.

Hook the low-pressure gauge to the service valve for the suction line and the middle hose to the nitrogen valve. Then connect the high-pressure gauge to the service valve for the liquid line, out by the condenser fittings. Release the gauges to give the system about 100 psi, and let the system hold the pressure for half an hour.

Check the gauge. If it is still at 100, then you don't have a leak. If it dips, find the leak by putting a mixture of dish detergent and water on the joints. Open the gauge to release the nitrogen and wait until the pressure reaches zero.

Hook the condenser, blower, evaporator and thermostat up to the electrical supply and turn the power back on.

Run the vacuum pump for at least an hour. Look at the gauge and make sure the pressure stays above 29 inches. Then, turn the valve off and turn off the pump. Watch the gauge for 15 minutes and make sure it stays steady.