38GXC(Q)/40GXC(Q) Service TrainingSizes 18 and 24K

.

NORMAL OPERATIONS

Red LED Yellow LED Green LEDCompressor Starts 1 Flash None

Defrost 2 Flashes H1Set Point Satisfied 8 Flashes None

Normal Communication Flash None

Outdoor Unit LED'sOperationIndoor Unit

Display

.

UNIT PROTECTION

Red LED Yellow LED Green LED

Freeze - 3 Flashes - E2Low refrigerant

charge or blocked indoor air flow

1

IPM - 4 Flashes - H5

Loss of cooling to heat sink, high

ambient temperature, low voltage, or bad

connection.

2

Over Current - 5 Flashes - E5

High ambient temperature,blocked outdoor coil, or

locked rotor current

3

Coil Temperature - 6 Flashes - E8High ambient or

loss of condenser air flow

4

Comp. Disch. Temp. - 7 Flashes - E4

Low refrigerant charge, blocked capillary tube, or

high ambient temperature

5

Comp. Temperature - 8 Flashes - H3

Low refrigerant charge,blocked

capillary, or compressor motor

failure

6

Low Voltage - - - PL - -High Volatge - - - PH - -

Possible Cause

Flow Chart #Protection Outdoor Unit LED's Indoor Unit

Display

.

COMPONENT FAILURES

Red LED Yellow LED Green LED

Outdoor Coil Sensor 5 Flashes - - F4Bad connection or

sensor failure 7

Outdoor Air Sensor 6 Flashes - - F3Bad connection or

sensor failure 7

Comp. Dish. Sensor 7 Flashes - - F5Bad connection or

sensor failure 7

Communication - - Off E6Wiring, indoor or

outdoor board failure

8

Return Air Sensor - - - F1Bad connection or

sensor failure 7

Indoor Coil Sensor - - - F2Bad connection or

sensor failure 7

Indoor Motor - - - H6Bad connection or

motor failure9

Failure Outdoor Unit LED's Indoor Unit Display

Possible Cause

Flow Chart #

.

COMPRESSOR FREQUENCY

Red LED Yellow LED Green LEDLimit frequency 1 Flash - - - Over current

Decrease frequency 1 Flash - - F8 Over current

Decrease frequency 2 Flashes - - F9High compressor

discharge temperature

Limit frequency 3 Flashes - - -Outdoor coil high

temperature

Decrease frequency 3 Flashes - - H0Outdoor coil high

temperatureDecrease frequency 4 Flashes - - - Freeze protection

Comp.Frequency Outdoor Unit LED's Indoor Unit Display

Possible Cause

.

18K HEAT PUMP WIRING DIAGRAM

.

24K HEAT PUMP WIRING DIAGRAM

.

18K COOLING ONLY WIRING DIAGRAM

.

24K COOLING ONLY WIRING DIAGRAM

.

Flow Chart 1 – Indoor Freeze Protection

No

Yes

Replace motor

Connect low side gauge atsuction service valves. Measure

discharge temp. OK?

No

Yes

Check for leaks.

Reclaim charge and fixleak.

Weigh in charge.

No

Clean indoor coil /filter of indoor unit with error message. Problem fixed?

Yes

No

Problem solved

Check indoor boardmotor/ thermistor output

Output ok?Replace indoor board.

Is system running within operating envelope?

System should not be operated

No

Yes

Yes

Check indoor thermistorsOK?

Replace thermistor

.

Flow Chart 2 – IPM Protection

Check heat sinks on back of board. OK?

Check if IPM module voltage between P

and N is around 300 V.

Check power supply to main board. OK?

No

Yes

No Clean and reattach. Ok?

Replace main board

Yes

Confirm there is voltage output and balance between any 2 phases of U,V, and W

Yes

Replace the compressor

Correct the powersupply connection

Problem solved

No

Yes

No

Yes

No

Flow Chart 3 – Compressor Over Current Protection

Is unit running in outdoorambient higher than 110 °F?

Beyond operating range

Outdoor coil clean? Clean coil.Problem persists? Problem solved

Check connections from OD board. Loose, corroded,or high resistance?

Check output onoutdoor board. Ok?

Connect low side gauge atsuction service valve. Measure discharge temp.*

Check amp draw to compressor? Values withinrange?

Replace outdoor board

Replace compressor

Clean/repair connection Problem persists?

Problem solved

Replace outdoor board

High head, high suction? High head, low suction?

Unit is overcharged. Reclaim charge and weigh in correct charge.

Yes

Yes

Yes

Yes

Yes

Yes

No

No

No

No No

No

No

Yes

Yes

No

No

Yes

Yes

Restriction in refrigeration circuit.

YesOutdoor motor ok?

No

Replace motor

*Measure discharge temperature at the sensor on the discharge tube.

Flow Chart 4 – High Condensing Temperature

Is unit running in outdoorambient higher than 110 °F?

Beyond operating range

Outdoor coil clean? Clean coil.Problem persists? Problem solved

Check outdoor coiltemperature thermistor.Chart 4, ok?

Check motor for openor short. Ok?

Check output on outdoorboard. Ok?

Replace outdoor board

Replace thermistor. Problem persists

Problem solved

Replace outdoor motor

Yes

No

No

Yes

No No

No

Yes

No

Yes

Yes

Yes

No

Flow Chart 5 – High Compressor Discharge Temperature

Check compressor discharge line thermistor. Ok?

Suction and discharge pressures low?

Check for leaks.

Reclaim charge and fixleak.

Weigh in charge.

Check for blocked capillary tube or a restriction

in liquid line

Ok

No

No

Yes

No

Yes

*Measure discharge temperature at the sensor on the discharge tube.

Connect low side gauge atsuction service valve. Measure discharge temp.*

NoReplace thermistor

Yes

High head, low suction?

Restriction in refrigeration circuit.

Yes

Flow Chart 6 – High Compressor Temperature

Check compressor Temperature switch Ok?

Suction and discharge pressures low?

Check for leaks.

Reclaim charge and fixleak.

Weigh in charge.

Check for blocked capillary tube or a restrictionin liquid line

Ok

No

Yes

No

Yes

*Measure discharge temperature at the sensor on the discharge tube.

Connect low side gauge atsuction service valve. Measure discharge temp.*

NoReplace switch

Yes

High head, low suction?

Restriction in refrigeration circuit.

Yes

No

Reset main power and restart system using remote.

Problem persists?

Check sensor resistance.

Appendix A4

No further action is required

No

Yes

Flow Chart 7 – Temperature Sensor

Check input and outputon indoor or outdoor board.

Yes

Check sensor connector at ID or OD board Connection good?

NoFix connection

Yes

NoReplace board

NoReplace sensor

Double check connection,for corrosion or high resistance.

Yes

Reset main power and restart system using remote.

Problem persists?

.

No further action is required

No

Yes

Flow Chart 8 – Communication Error

Measure Volts DC onoutdoor TB between S & L2

(0-24VDC) Ok?**

Yes

Check the wires (type) and connections betweenIndoor and outdoor units*

No

Fix connection or replace wiring

No

Yes

Replace outdoor board.

* Thermostat wires cannot be used. Wires should be connected per connection diagrams. Failure to do that will result in a communication error. Polarity needs to be maintained between indoor and outdoor units.** There is 3 minutes to make the measurement before the diagnostic light comes back on.

Measure Volts DC onindoor TB between S & L2

(0-24VDC). Ok?**

No

Replace indoor board.

Recheck wiring and connections

Notes:

Before measuring the Volts DC on outdoor TB,disconnect the field wire on terminal S.

Before measuring the Volts DC on Indoor TB,disconnect the field wire on terminal S.

Have the red probe of the meter on terminal Sand the black probe on terminal N. Reconnect wiring when measurements are complete.

Reset circuit breaker. Is problem fixed?

Problem fixedYes

Yes

No

Reset main power and restart system using remote.

Problem persists?

Replace indoor fan motor

No further action is required

No

Yes

Flow Chart 9 – Indoor Fan

Check IFM output and and input on indoor

board. Values good?

Yes

Check motor connection. Connection good?

NoFix connection

Yes

NoReplace indoor board

TEMPERATURE/PRESSURE CHART

Cooling:

Compressor Suction Discharge Compressor Suction DischargeSpeed Pressure Temperature Speed Pressure Temperature(Hz) (PSI) (F) (Hz) (PSI) (F)

55 (Min) 18 154 78 18 165 7355 (Max) 78 93 144 88 98 14575 (Min) 18 178 93 18 185 8275 (Max) 78 103 164 88 108 16395 (Min) 18 190 106 18 206 10095 (Max) 78 118 185 88 125 177115 (Min) 18 210 124 18 226 112115 (Max) 78 130 207 78 137 194

Heating:

Compressor Suction Discharge Compressor Suction DischargeSpeed Pressure Temperature Speed Pressure Temperature(Hz) (PSI) (F) (Hz) (PSI) (F)

17/15 (Min) 18 77 62 18 76 5417/15 (Max) 77 58 133 92 56 11935/33 (Min) 18 104 94 18 108 7535/33 (Max) 77 83 180 92 83 16347/43 (Min) 18 130 96 18 132 8047/43 (Max) 77 100 202 92 101 190

62/57 (Min) 18 164 105 18 165 8762/57 (Max) 77 133 197 92 135 189

Indoor 75/-- F, Outdoor Ambient

(F)

18K 24K

Indoor 80/67 F, Outdoor Ambient

(F)

18K 24K