Service Manual

Table Of Contents

2) Defrost Termination: DTh warms to 44°F (6.6°C). If not, conrm DTh status.

See "II.D. Thermistor Check." If DTh is in proper range, Comp icon turns on and

Comp, ConFM, and MH (PT2A and R_2A models) energize. 15-min. temperature

display timer starts. Once 15-min. temperature display timer terminates, "dEF" is

replaced by cabinet temperature on display.

(1) Comp energized: DTh warms to 44°F (6.6°C), conrm Comp icon turns on and

Comp and ConFM energize. If not, conrm cabinet temperature is warm enough

for Comp operation. Next, check for 115VAC at CM1 (C) (V) to neutral(W).

If115VAC is not present, check CTh status. See "II.D. Thermistor Check."

If CTh ohm reading is in proper range, Comp icon is on, and 115VAC is not

present at CM 1 (C) (V), replace CM. If 115VAC is present, check for 115VAC at

CUR (V). If 115VAC is present at CM1 (C) (V) to neutral (W) and not at CUR (V),

check HPS continuity. See "1.5)h) HPS Activation" above. If HPS is closed and

115VAC present, check for 115VAC at condensing unit power supply cord (BK) to

neutral (W).If 115VAC is not present at condensing unit power supply cord (BK),

replace condensing unit power supply cord. If 115VAC is present at condensing

unit power supply cord (BK) and ConFM is energized but Comp is not, check

for 115VAC at Comp external protector to neutral (W). If 115VAC is not present,

give time for external protector to cool and reset. If Comp external protector does

not reset, replace Comp external protector. If 115VAC is present on both Comp

external protector wires, check run capacitor, start capacitor, start relay, and

Comp motor windings. If ConFM is not energized, check ConFM fan blades for

binding and motor winding continuity. If Comp does not start, replace condensing

unit.

(2) 15-min. temperature display delay timer terminates: 15 min. after Comp

icon turns on and Comp and ConFM energize, "dEF" is replaced by cabinet

temperature on display. If not, replace CM.

Legend: BH–bottom heater; CL–cabinet light; CM–control module; Comp–compressor;

ConFM–condenser fan motor; CTh–cabinet thermistor; DCD–direct current driver;

DS–door switch; DTh–defrost thermistor; EvapFM–evaporator fan motors;

HPS–high-pressure switch; MH–mullion heater; TXV–thermostatic expansion

valve; TXVH–thermostatic expansion valve heater; CUR–condensing unit

receptacle