Lennox Harmony II Zone Control System Installation Instructions Manual page 37

LED Display
Diags
Service Light
(Control Center)
(Control Panel)
Off On
Code #13
DIAG
1
DIAG
FLASHING
2 2
DIAG
3
DIAG
4
OFF
Code #14
DIAG
1
DIAG
FLASHING
2 2
DIAG
3
DIAG
4
OFF
Code #15
FLASHING
DIAG
1 1
DIAG
2
DIAG
3
DIAG
4
Error
Description
Discharge Air Probe
Has Sensed Dis- Has Sensed Dis-
charge Air Warmer
Than 130_F.
Discharge Air Probe
Has Sensed Dis Has Sensed Dis-
charge Air Cooler
Than 45_F.
High Pressure High Pressure
Switch Has Sensed
Liquid Line Pres-
sure Greater Than
275psig.
OFF
Table 9
Fail-safe Fail-safe
(System Shut
Down)
If service alert light is flashing*:
1) Cooling equipment has failed to cool sufficiently after 4 min-
utes, check outdoor equipment.
2) Discharge probe has failed, replace probe.
3) If error persists, replace control center.
*See IMPORTANT in the Troubleshooting section..
No
If service alert light is not flashing:
1) Heater is causing plenum to be too warm (overcapacity). Try
increasing air to smallest zone.
2) Dirty filter, coil or other restriction to airflow.
If service alert light is flashing*:
1) Heating equipment has failed to heat sufficiently after 4-1/2
minutes, check heating equipment.
2) Discharge probe has failed, replace probe.
3) If error persists, replace control center.
*See IMPORTANT notice in the Troubleshooting section.
No
If service alert light is not flashing:
1) Cooling is causing plenum to be too cool (overcapacity). As
long as cooling demand is present, compressor will run for 4
minutes then cycle off for 5 minutes. Try increasing air to small-
est zone.
2) Dirty filter, coil or other restriction to airflow.
Service alert light will flash only if the error is still present 5
minutes after the compressor has cycled off and only if the IN-
DOOR UNIT jumper is set for heat pump. Once set, the com-
pressor is locked out and cannot be energized to satisfy a heat-
ing demand:
1) The discharge air probe has probably failed and needs re-
placement or
2) If the INDOOR UNIT jumper block has been set for G21V or
GAS, there should not be a pressure switch installed and the
control center has failed.
If the control center and discharge air probe are alright, a se-
vere system problem may be indicated:
3) Check refrigeration system for blockage.
4) If FM21, check for indication of overheating indoor coil.
If the service alert light is not flashing when this code is set
(heating or cooling), high liquid operating pressures are indi-
No
cated:
1) Try Increasing airflow to the zones calling beginning with the
smallest zone.
2) Check for dirty filters or other airflow restrictions.
When capacity is too high for the zones calling the following op-
eration will be observed:
in heating:
If the condition persists for 6 minutes of low speed (or single
speed) compressor operation, the compressor will shut off for
5 minutes to allow pressures to balance. If the condition occurs
during high speed heating, the compressor will be switched to
low speed for 90 seconds. if the condition is still present after
90 seconds, the compressor is shut off for 5 minutes.
in cooling:
This error code has no effect on cooling operation.
Page 37
Remedy