43
Table 29 — Troubleshooting (cont)
FAULT
COOLING
HEATING
CHECK
POSSIBLE CAUSE
SOLUTION
High humidity
X
Airflow too high
Fan speed setting too
high
Consult blower performance table and reduce fan
speed if possible.
Loss of refrigeration
capacity
Low refrigerant
Check refrigerant pressures with gage set.
Short cycling
Unit oversized
Check unit performance against building load calcula-
tions.
Poor thermostat location
Make sure that thermostat is not located by a supply-
air duct.
Objectionable noise
levels
X
X
Air noise
Poor ductwork/grille design
Ensure ductwork and grilles are properly sized for unit
airflow.
Fan speed setting too high
Consult blower performance table and reduce fan
speed if possible.
Structure bourne
noise
Unit not mounted on full vibra-
tion pad
Mount unit on a vibration pad.
Unit not connected with flexi-
ble conduit, water lines and/or
ductwork
Install unit in accordance with instructions.
Unit cabinet touching wall or
other building component
Adjust unit location to avoid unit touching structure.
X
Compressor noise
High water temperature or low
water flow rate elevating head
pressure
Increase water flow rate and/or reduce water tempera-
ture if possible.
Scaled or fouled water coil
elevating heat pressure
Clean/descale water coil.
X
Low airflow elevating head
pressure
Check filter.
Increase fan speed.
X
X
Water hammer
Fast closing valves installed
Change valves to slow-close type.