Reznor MAPS - A,B,C Users Manual Bedienungsanleitung PDF herunterladen (Seite 33)

Form O-MAPSIII&IV Cabinets A/B/C, P/N 257004R8, Page 33

H. High discharge

pressure.

1. Refrigerant overcharge 1. Check subcooling. (Paragraph 3.5) Adjust refrigerant charge.

2. Thermal expansion valve setting 2. Check superheat and adjust valve as needed.

2. Air inlet to condenser dirty or obstructed. 3. Check for proper clearances and possible air recirculating.

4. Condenser fan motor defective. 4. Check condenser fan motor(s).

I. Suction

pressure is too

low.

1. Refrigerant undercharge. 1. Check subcooling. (Paragraph 3.5) Add refrigerant as needed.

2. Thermal expansion valve setting 2. Check superheat and adjust valve as needed.

3. Blower running backward. 3. Interchange any two wires from 3 phase disconnect.

4. Loose blower, pulley, or belts. 4. Check drive pulley alignment and belt tension.

5. Dirty lter. 5. Check lter and evaporator coil.

6. Too little air ow or low entering air temperature. 6. Check airow and entering air wet bulb conditions.

7. Restriction in suction or liquid line. 7. Check refrigerant circuit for restriction.

J. Head pressure

too low.

1. Insufcient refrigerant charge. 1. Check subcooling (Paragraph 3.5). Check for leak. Repair and add refrigerant.

2. Defective or improperly adjusted expansion valve. 2. Check superheat (Paragraph 3.5) and adjust thermal expansion valve.

3. Low suction pressure. 3. See “I. Suction pressure too low” above.

4. Defective compressor. 4. See "G. High suction pressure” above.

K. Compressor

short cycles.

1. Improper refrigerant charge. 1. Check subcooling and superheat. (Paragraph 3.5)

2. Defective high or low pressure control. 2. Check high or low pressure switch.

3. Liquid oodback. 3. Possible tight bearings, see above.

4. Defective expansion valve. 4. Check superheat and thermal expansion valve.

5. Poor air distribution. 5. Check ductwork for recirculating.

6. High discharge pressure. 6. See “H. High discharge pressure” above.

7. Leaking discharge valves in compressor. 7. See “G. High suction pressure” above.

L. Running cycle

is too long or

unit operates

continuously.

1. Refrigeration undercharged. 1. Check subcooling (Paragraph 3.5) and add refrigerant.

2. Dirty lter or evaporator coil. 2. Check lter, coil, and airow. Clean and/or replace.

3. Dirty or clogged condenser coil. 3. Check coil and airow. Clean.

4. Air or other non-condensables in system. 4. Check equalized high side pressure with equivalent outdoor temperature.

5. Defective compressor. 5. See “G. High suction pressure” above.

6. Restriction in suction and liquid line. 6. Check for restrictions in refrigerant circuit.

7. Control contacts stuck. 7. Check wiring.

M. Supply air

temperature is

too high.

1. Refrigerant undercharge or leak in system. 1. Check subcooling (Paragraph 3.5). Check for leak. Repair and add refrigerant.

2. Evaporator plugged with dirt or ice. 2. Check evaporator, airow, and lter. Clean.

3. Improperly adjusted or defective expansion valve. 3. Check superheat (Paragraph 3.5) and adjust thermal expansion valve. Check

expansion valve bulb placement and insulation.

4. Defective compressor. 4. Check compressor for proper operation.

5. High discharge pressure. 5. See “H. High discharge pressure” above.

6. Airow is too high. 6. Check external static pressure.

N. Supply air

temperature is

too low.

1. Airow is too low. 1. Check evaporator coil; check lters; check for closed dampers or grills; check

drive for loose parts, belts, or misalignment; and check external static pressure.

2. Return air temperature too low. 2. Check entering air wet bulb conditions.

O. Liquid line is

too hot.

1. Refrigerant undercharge. 1. Check subcooling.

2. High discharge pressure. 2. See H. above.

Compressor Digital Controller LED’s

LED State

Indicates Additional Information

Color CODE

Green Solid Power (24VAC present at

power terminals)

Modulating capacity compressor starts only when

demand signal input is above 1.45 VDC and no

ALERTS (red LED ashes) are active.

Green. Flashing Anti-short cycle timer is

active

Yellow Solid Unloader (Solenoid valve

is energized; compressor

capacity is 0.)

Modulating capacity compressor always unloads for 0.1

second at startup.

Red Not lit No abnormal operation

alerts

Red 2 Flashes High Discharge

Temperature Alert

(thermistor temperature

above 268°F or

thermistor is short

circuited)

Modulating capacity compressor will be allowed to

restart after a 30-minute delay and after the thermistor

temperature is below 250°F. Compressor will lockout

after 5 alerts within 4 hours and can only be reset by

cycling the 24VAC power off and on.

7.2 Compressor

Digital

Controller

Troubleshooting

- all MAPS

Models

General - The digital controller is located in the electrical compartment and acts as the

interface between the digital compressor and the unit controller. If the unit interface dis-

play indicates critical Alarm Code 17, Modulating Capacity Compressor Failure, check

the LED lights on the digital controller.

The alert code (red LED ashes) on the digital controller remains active and the com-

pressor de-energized until the reset conditions have been met or the 24VAC power

is cycled off and on. All Codes except 6 result in compressor (contactor and unloader

valve) being de-energized.

(continued)

NOTE: To identify MAPS

Models, see Paragraph 1.0.

1 2 ... 28 29 30 31 32 33 34 35 36 37 38 39 40

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