Troubleshooting
80 CLCH-SVX013B-EN
Low refrigerant
coil capacity
Incorrect airflow
Check fan operating condition.
Expansion valve is not operating properly or is sized
incorrectly
Check sensing bulb temperature.
Verify valve operation.
Verify proper valve size.
Incorrect refrigerant charge
Verify refrigerant charge and adjust if necessary.
Condensing unit failure Verify condensing unit operation.
Coil is piped incorrectly Verify coil piping (see “Piping and Connections,” p. 42
).
Clogged refrigerant line filter Change filter core.
Failure of suction/liquid line components
Verify component operation
Dirty fin surface
Clean the fin surface (see “Coils,” p. 73).
Do not use steam to clean refrigerant coils.
Fin frosting
Verify defrost cycle operation.
Verify frostat operation.
Verify refrigerant charge.
Low steam coil
capacity
Incorrect airflow Check fan operating condition.
Coil is piped incorrectly Verify coil piping (see “Piping and Connections,” p. 42
).
Incorrect steam pressure Verify steam pressure and adjust if necessary.
Excessive steam superheat
Check steam superheat.
Steam superheat should not exceed 50ºF.
Failure of steam line/condensate return components Verify component operation
Boiler failure
Verify boiler operation
Dirty fin surface Clean the fin surface (see “Coils,” p. 73).
Drain pan is
overf
lowing
Plugged Drain Line
Clean drain line
Unit not level Level unit
Improper trap design Design trap per unit installation instruc
tions
Standing water
in drain pan
Improper trap design Design trap per unit installation instructions
Unit not level
Level unit
Plugged drain line Clean drain line
Wet interior
Coil face velocity too high
Reduce fan speed
Improper trap design Design trap per unit installation instructions
Drain pan leaks/overflows
Repair leaks
Condensation on surfaces Insulate surfaces
Excess dirt in
unit
Mi
ssing filters
Replace filters
Filter bypass Reduce filter bypass by ensuring all blockoffs are in place.
Microbial growth
(mol
d) inside air
handler
Standing water in drain pan See “Standing water in drain pan” above
UV light fails
Ballast fails to energize light.
Disconnect high voltage leads (green, white, and black connectors) from
the ballast enclosure. Wait for three minutes, this will reset the end-of-
light circuitry and then reconnect.
End of life. Replace bulb. See “Replacing the Bulbs,” p. 77.
Table 17. Air handler troubleshooting recommendations
Symptom Probable Cause Recommended Action
To Next Page
Loading...
