Specifications

5.0 CHARGING

5.1 Voltage Phase Check

5.1.1 Evaporator

Prior to charging, the correct voltage phasing should be checked on the indoor evaporator. It

is easiest to check the blower direction on the evaporator with standard poly-phase motors by

momentarily moving the blower manual bypass switch located in the DAP-III control module to the ON

position, then back to the OFF position (there is a Power ON/OFF switch above the blower bypass

switch that must in the ON position before running the blower). Reverse any two of the three line

voltage wires at the line voltage ﬁ eld connection point to change the blower rotation.

Although scroll compressors are phase dependent, units shipped from the factory are run tested,

ensuring the compressor rotation is consistent with the evaporator fan motor. However, a ﬁ eld

change-out of a compressor may require checking proper phase. An out-of-phase compressor will

draw relatively low amps and both suction and discharge pressures will remain nearly equal.

5.1.2 Secondary Heat Exchanger

The secondary heat exchanger may be ordered as three phase but the individual fan motors are

single phase and will only run in one direction. Check operation by placing a momentary jumper

across low voltage ﬁ eld terminals # 30 and # 40. (Disconnect pumps on glycol systems unless already

ﬁ lled with water/glycol solution.) This will energize the control circuit. Fans may not turn because

either the thermostat setpoint is above the current ambient temperature or the # 1 fan (on air cooled

condensers with fan speed control) has not reacted to the head pressure. On systems with R-410A

the fan will not operate until the head pressure is beyond 300 PSIG. Units with R-407C the head

pressure must reach 200 PSIG.

5.2 Important Refrigeration Components

5.2.1 Expansion Valve

Each refrigerant circuit has an adjustable thermo-expansion valve (TXV). These are factory

adjusted to their nominal rating. Any ﬁ eld adjustment should be to ﬁ ne tune a system that has

stabilized and already has acceptable operating parameters. Adjusting a TXV to produce large

swings in superheat is not recommended.

5.2.2 High Pressure Cutout Switch

Each refrigerant circuit is protected by a high head pressure cutout switch with manual reset

button. The switch is typically located in the evaporator near the compressors.

The pressure rating for R-410A is 610 PSIG. The pressure rating for R-407C is 400 PSIG.

5.2.3 Low Pressure Cutout Switch

Each refrigerant circuit has a low pressure cutout switch with automatic reset. The switch is

located near the compressors.

The pressure rating for R-410A is 50 PSIG. The pressure rating for R-407C is 28 PSIG.