Carrier 48/50PG C03-14 manual Humidi−MiZert Troubleshooting, Humidi-MiZerService Analysis

Humidi−MiZert Troubleshooting

Use the unit Scrolling Marquee display or a CCN device to view the cooling status display and the cooling diagnostic display (see Appendix A) for information on the cooling operation and the related Humidi-MiZeroperation. Check the current alarms and alarm history for any cooling alarm codes and correct any causes. (See Table 12.) Verify any unique control configurations per installed site requirements or accessories.

If alarm conditions are corrected and cleared, operation of the compressors, fans, and Humidi-MiZer valves may be verified by using the Service Test mode. (See Table 4.) In addition to general cooling service analysis (See Table 14), see Table 15 for general Humidi-MiZer service analysis.

NOTE: Wiring, operation, and charge are different on a Humidi-MiZer unit compared to a standard unit.

Table 15 – Humidi-MiZer Service Analysis

48/50PG and PM

PROBLEM

Subcooling Reheat Mode

Will Not Activate.

Hot Gas Reheat Mode

Will Not Activate.

No Dehumidification Demand.

CRC Relay Operation.

CV or RH1 Valve Operation. (NOTE: Normally Open When De‐energized)

RH2 Valve Operation.

(NOTE: Normally Closed

When De‐energized)

Low Latent Capacity in Subcooling or Hot Gas Reheat Modes.

Low Sensible Capacity in Normal Cool or Subcooling Reheat Modes.

Low Suction Pressure and High Superheat During Normal Cool Mode.

Low Suction Pressure

and High Discharge Pressure.

RH2 Valve Cycling On/Off.

Circuit B or C Will Not Operate With Circuit A Off.

LEGEND

CRC - Cooling/Reheat Control

CV - Cooling Valve

RH - Relative Humidity

CAUSE

General cooling mode problem.

No dehumidification demand.

CRC relay operation.

Circuit RH1 valve is not open.

Circuit CV valve is not closed.

General cooling mode problem.

No dehumidification demand.

CRC relay operation.

Circuit RH1 valve is not open.

Circuit CV valve is not closed.

Circuit RH2 valve is not open.

Outdoor temperature too low.

Relative humidity setpoint is too low — Humidistat

Relative humidity setpoint is too low — RH sensor.

Software configuration error for accessory humidistat.

Software configuration error for accessory humidity sensor.

No humidity signal.

No 24V signal to input terminals.

No power to output terminals.

Relay outputs do not change state.

No 24V signal to input terminals.

Solenoid coil burnout.

Stuck valve.

No 24V signal to input terminals.

Solenoid coil burnout.

Stuck valve.

CV valve open or leaking.

RH2 valve open or leaking.

General cooling mode problem.

RH2 valve open or leaking.

General cooling mode problem.

Both RH1 and CV valves closed.

Hot Gas Reheat mode low suction pressure limit.

Normal operation. Motormaster outdoor fan con­ trol requires operation of circuit A.

REMEDY

See Cooling Service Analysis (Table 14).

See No Dehumidification Demand, below.

See CRC Relay Operation, below.

See RH1 Valve Operation, below.

See CV Valve Operation, below.

See Cooling Service Analysis (Table 14).

See No Dehumidification Demand, below.

See CRC Relay Operation, below.

See RH1 Valve Operation, below.

See CV Valve Operation, below.

See RH2 Valve Operation, below.

Check Reheat2 Circuit Limit Temperatures (Configuration→HMZR→RA.LO and RB.LO) using ComfortLink Scrolling Marquee.

Check/reduce setting on accessory humidistat.

Check Space RH Setpoints (Setpoints→RH.SP and RH.UN) and occupancy using ComfortLink Scrolling Marquee.

Check Space Humidity Switch (Configuration→ UNIT→RH.SW) using ComfortLink Scrolling Marquee.

Check RH Sensor on OAQ Input (Configuration→ UNIT→RH.S) using ComfortLink Scrolling Marquee.

Check wiring. Check humidistat or humidity sensor.

Check using Cool→Reheat1 Valve Test (Service Test→HMZR→CRC) using ComfortLink Scrolling Marquee.

Check MBB relay output. Check wiring.

Check transformer and circuit breaker.

Check wiring.

Replace faulty relay.

Check using Cool→Reheat1 Valve Test (Service Test→HMZR→CRC) using ComfortLink Scrolling Marquee.

Check CRC Relay Operation. Check Wiring.

Check transformer and circuit beaker or fuses.

Check continuous over‐voltage is less than 10%.

Check under‐voltage is less than 15%.

Check for missing coil assembly parts. Check for damaged valve enclosing tube. Replace valve. Replace filter drier.

Check using Cool→Reheat1 Valve Test (Service Test→HMZR→RHV.A or RHV.B) using ComfortLink Scrolling Marquee.

Check MBB relay output. Check wiring.

Check transformer and circuit breaker or fuses.

Check continuous over‐voltage is less than 10%.

Check under‐voltage is less than 15%.

Check for missing coil assembly parts.

Check for damaged valve enclosing tube.

Replace valve. Replace filter drier.

See CV Valve Operation, above.

See RH2 Valve Operation, above.

See Cooling Service Analysis (Table 14).

See RH2 Valve Operation, above.

See Cooling Service Analysis (Table 14).

See RH1 and CV Valve Operation, above.

Normal Operation During Mixed Circuit Subcooling and Hot Gas Reheat Modes at Lower Outdoor Temperatures.

None

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