Trane Modular Air Handler MCC 524 ZB

After completion of leak check, evacuate the system

Attach appropriate hoses from manifold gauge to gas and liquid line pressure taps

Note: Unnecessary switching of hoses can be avoided and complete evacuation of all lines leading to sealed system can be accomplished with manifold center hose and connecting branch hose to a cylinder of R-22 and vacuum pump

Attach center hose of manifold gauges to vacuum pump

Evacuate the system to hold a 350 micron vacuum

Close off valve to vacuum pump and observe the micron gauge

If gauge pressure rises above 500 microns in one (1) minute, then evacuation is incomplete or the system has a leak

If vacuum gauge does not rise above 500 microns in one (1) minute, the evacuation should be complete

After the connection operation of refrigerant lines to both the outdoor and indoor unit is completed, the field brazed connections must be checked for leaks

Pressurize the system through the service valve with dry nitrogen to 250 psi

Use soap bubbles or other leak-checking methods to ensure that all field joints are leak free

If not, release pressure, repair and repeat leak test

Sign off on the air handler leak test

Charge the refrigerant until pressure at gauge is up to 120-150 psi

Once the charge enters the system, backseat (open) the liquid line service valve and disconnect the charging line and replace the cap on the gauge port

Gaseous Charging: This procedure is accomplished with the unit operating. Electrical connections must be complete. Do not proceed until the system is ready to operate.

Connect R-22 drum with gauge manifold to the Schrader valves (pressure taps) on the compressor discharge and suction lines

Turn on power to the unit. Allow the system to run for five to ten minutes to stabilize operating conditions

Once proper airflow is established, observe the suction and head pressure gauges on the gauge manifold. Pressure reading should fall approximately at the normal points. Add or remove refrigerant (gas only) as required to obtain correct head and suction pressures

Check suction line superheat and condenser sub-cooling to ensure the unit is operating properly

Disconnect all power to the unit

Remove the charging system from the unit and close the opening in the bottom of the control box with the pivotal cover before attempting to replace access panel