Lennox Harmony II Zone Control System User Manual

Page 39
Option 2 − Troubleshooting Harmony
®
II Zone Control with Lennox Heat Pump
Figure 30
 Line Voltage to transformer?
 24VAC from transformer to control center?
 Fuses OK?
 Are all wire connections good? Are all wire
connections correct?
 Error code present? If so,
see diagnostic section of
this manual.
 Are LEDs on panel lit? Check
wiring?
 Does panel readily switch be-
tween Zone, Central and Off?
 Does panel readily switch be-
tween Cool, Heat and Auto?
 Does panel readily switch be-
tween Fan On and Auto?
 Are wires run adjacent to AC
line voltage wires?
 Is wiring correct and in good
condition?
 Do dampers respond to de-
mand? 0 volts AC = open.
24 volts AC = closed.
Dampers should drive
closed when 24 volts is
jumpered to damper motor.
 Are jumpers set correctly?
 Only one jumper is allowed
per zone.
 Is switch installed in compres-
sor discharge line between
compressor and reversing
valve?
 Does switch open when high
pressure condition is simulated
(temporarily blocking airflow in
heating mode)?
 Does control center respond
appropriately when high pres-
sure condition is simulated
(temporarily disconnecting
switch simulates high pres-
sure).
 Heat pump thermostat used?
(Must not use heat/cool thermo-
stat.)
 If electronic thermostat is used,
does it have relay switching out-
put? If relay with SCR output is
used, isolation relays may need
to be used.
 24VAC supplied to each thermo-
stat terminal R from control cen-
ter?
 Check each thermostat for output
signal when calling. Heating out-
put? Y1, Y2, W1.
Cooling output? Y1, O, Y2
Blower output not used, no need
to check.
 Are anticipators working?
 Is discharge probe installed?
 Probe should be located in discharge air
plenum before first bend or branch. Is
probe in correct location?
 Is it wired correctly?
 After 5 minutes heating operation, is dis-
charge air between 95F and 125F?
 After 5 minutes cooling operation, is dis-
charge air between 53F and 70F?
 Is jumper set correctly? Heating
air reduction must be set to 0%.
 Does jumper provide appropriate
speed reduction? If no, check in-
door unit before replacing control
center.

Is jumper set correctly?
 Up to two jumpers may be used.
 If two jumpers are used, one must
be on a C terminal and the other on
an H terminal.
 Is jumper set correctly for
stages of auxiliary heat?
 Are appropriate outputs
energized in response
to demand?
 Are thermostats wired correctly?
 Does control center respond appro-
priately to demand?
This troubleshooting diagram lists common trouble spots. Rather than providing solutions, this diagram asks questions
about the hookup and operation of system equipment Good troubleshooting skills combined with information provided
elsewhere in this manual are necessary.
 Does control center energize ap-
propriate outputs? During Cool-
ing? During Heating? During De-
frost? During Em. Heat?
 24VAC from indoor unit trans-
former to R?
 Does indoor unit respond to
outputs? Cooling? Heating?
Defrost? Em. Heat?
 Does blower speed change
as zone demand changes? If
no, does DS output vary from
0 to 25VDC?
 Does outdoor unit respond to
demand?
 Is it operating properly?
 Test defrost. Does outdoor
unit initiate and terminate de-
frost correctly?
 Is W1 energized during de-
frost?
 Does control center respond
appropriately during defrost?
or GAS

Lennox Harmony II Zone Control System Specifications

General

Brand	Lennox
Model	Harmony II Zone Control System
Category	Control Systems
Language	English