Carrier AQUAZONE 50KQE Series Installation, Operation And Maintenance Instructions

Contents

Carrier AQUAZONE 50KQE Series Installation, Operation And Maintenance Instructions Manual pdf 28 page image

2810 - TROUBLESHOOTINGWhen troubleshooting problems with a water-source heat pump,consider the following and refer to Table 14:10.1 - ThermistorA thermistor may be required for single-phase units wherestarting the unit is a problem due to low voltage.9.10 - Safety control resetThe 50KQE heat pumps are furnished with high pressure, lowpressure and low temperature cutouts to prevent the machine fromoperating at abnormal conditions of temperature or water flow.The contacts of the high pressure control used on 50KQE unitsis designed to open at 2600 kPa and automatically re-close at2100 kPa. The Complete C or Deluxe D control monitors this andother functions such as refrigerant temperatures and pressuresand condensate overflow and will interrupt unit heating orcooling operation.The machine must be reset manually. Reset is accomplished bypressing the STOP button and then pushing either HI HEAT,LOW HEAT, HI COOL or LO COOL to restart the unit in thedesired mode of operation. (The 50KQE unit can also be resetby opening and closing the supply power disconnect switch.)NOTE: If the unit must be reset more than twice, check theunit for a dirty filter, abnormal entering water temperature,inadequate or excessive water flow, and internal malfunctions.If the unit continues to cut out, contact a trained servicetechnician.WARNING: When replacing the compressor contactor orlockout relay in a unit with electromechanical controls, useonly Carrier factory authorized parts. Substitution of othercomponents may result in an inoperative safety circuit andmay cause a hazardous condition.9.11 - Checking system chargeUnits are shipped with full operating charge. If recharging isnecessary:1. Insert thermometer bulb in insulating rubber sleeve onliquid line near filter drier. Use a digital thermometer forall temperature measurements. DO NOT use a mercury ordial-type thermometer.2. Connect pressure gauge to discharge line near compressor.3. After unit conditions have stabilised, read head pressureon discharge line gauge.NOTE: Operate unit a minimum of 15 minutes before checkingcharge.4. From standard field-supplied pressure-temperature chartfor R-407C, find equivalent bubble point temperature.5. Read liquid line temperature on thermometer; thensubtract from bubble point temperature. The differenceequals subcooling temperature.9.12 - Refrigerant chargingWARNING: To prevent personal injury, wear safety glassesand gloves when handling refrigerant. Do not overchargesystem - this can cause compressor flooding.NOTE: Do not vent or depressurise unit refrigerant to atmos-phere. Remove and reclaim refrigerant following acceptedpractices.