Master-Bilt Master Controller 2.0 User Manual

Master Controller Reverse Cycle Defrost Startup Guide

Installation Requirements:

• Reverse Cycle Defrost (RCD) requires liquid line one size larger than standard, insulated

• RCD requires two pairs low voltage wire evaporator to condensing unit

• Coil Outlet Probe mounts 6” from evaporator on suction line, well insulated

• Refrigerant charge must be measured, charge to superheat readout (SH) only

• Break vacuum with drum on scale

Charging Procedure:

• ½ - 1½ HP: Initial Charge: 1lb., Additional Incremental Charge(s): 8 oz.

• 2 – 4 HP: Initial Charge: 2lb., Additional Incremental Charge(s): 8 oz.

• 5 HP and Larger: Initial Charge: 3lb., Additional Incremental Charge(s): 1 lb.

• Allow (5) minutes between Initial Charge and subsequent Incremental Charge(s) to observe

reduction and stabilization of Superheat (SUPH)

• When Superheat reaches 20-24° stop charging for (30) minutes, then observe (SH) at

reduced space temperature

• If Superheat (SUPH) is 8-12°F no additional Incremental Charge is required

• Target Superheat readout at (SUPH) is 10°F, same as (SHSP) setpoint

NOTE: For locations with extreme low ambient temperatures it may be advisable to increase

the final refrigerant charge amount, determined by the above method, by 20%

Record the final charge amount on the evaporator coil end panel behind the controller and

conspicuously on the condensing unit. A permanent marker or printed strip label (Dymo, PTouch)

is best.

Final Checks:

• Check all factory default set points per list on Page 30 of Condensing Unit Installation and Operations Manual

• Adjust Room Temperature Cut Out at (RMSP) if required, defaults +35 cooler, -10 freezer

• Adjust Temperature Differential to Cut In at (ADIF) if required, defaults 3° cooler, 5° freezer

• Adjust condensing unit Low Pressure Control to (2lb.) cut-out and (25lb.) cut-in by gauge

908 Highway 15 North • New Albany, Mississippi 38652

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E-mail: [e-mail] • Website: www.master-bilt.com