Troubleshooting Diagrams - Lennox Harmony III Installation Instructions Manual

Troubleshooting Diagrams

System Troubleshooting − Harmony IIIt Zone Control System Option 1 −
Lennox Variable-Speed Gas Furnace and Lennox Condensing Unit
-
Are thermostats wired correctly?
-
Does zone control system respond appropriately to demand?
-
Heat/cool thermostat used? (Must not use heat pump thermostat.)
-
Does electronic thermostat have relay switching output? If not, isolation relays may
need to be used.
-
24VAC supplied to each thermostat terminal R from zone control system?
-
Check each thermostat for output signal when calling. Heating output? Cooling output?
-
[No pressure Switch should be installed.]
-
Do dampers respond to demand? 0
volts AC = open. 24 volts AC =
closed. Dampers should drive closed
when 24 volts is jumpered to damper
motor.
-
Is wiring correct & in good condition?
DAMPERS
-
Is discharge
probe
installed?
-
Is probe lo-
cated in dis-
charge air ple-
num as de-
scribed on
Page 5?
-
Is it wired cor-
rectly?
DISCHARGE AIR SENSOR
-
Are Reduction jump-
ers set correctly?
-
Do jumpers provide
appropriate speed re-
duction? If no, check
indoor unit before re-
placing zone control
board.
-
Are PIAB jumpers
set correctly?
-
Only 1 jumper per
Zone? (Zone Con-
trol System Jump-
er Settings
(Page 8)
Thermostat 4
PS PS BPS BPS W C Y G R
Damper1
NC
NO
C
Damper2
NC
heat/cool staging
jumper settings − page
NO
11.
C
Damper3
Heating
Staging Temp
NC
85
90
NO
100
110
C
120
130
Damper4
Cooling
NC Staging Temp
50
NO
55
NotUsed
60
C
Cont. Air
Reduction
das 0%
25%
50%
75%
Heating Air '
Reduction
air reduction jumper
0%
settings − page 9.
20%
40%
ESD CAUTION
Vacation
TOUCH A GROUNDED METAL
Mode
OBJECT BEFORE TOUCHING
Selector
THE CIRCUIT BOARD
LENNOX
Harmony IIIt
V3.0 2004
E−Heat
Selector
Fault
TDO Recall
damper 4 damper 3 Damper 2 Damper 1
- -
Are jumpers set cor-
rectly for furnace and
cooling? (Page 11)
Thermostat 2
THERMOSTATS
W C Y G R
Thermostat 3
W C Y G R
W C Y G R
piab jumper settings −
page 8.
Zone1 Zone3
PIAB PIAB
0%
OFF
10%
0%
20%
10%
30% 20%
40%
30%
50%
40%
60%
50%
70%
60%
80% 70%
90%
80%
100% 90%
100%
Zone2 Zone4
PIAB PIAB
OFF
OFF
0%
0%
10%
10%
20%
20%
30%
30%
40%
40%
50%
50%
60%
60%
70%
70%
80%
80%
90%
90%
100%
100%
SYSTEM E−HEAT
Configuration Stages
HP GAS DF
1
2COOL 1COOL
2
2HP 1HP
3
System Configuration & E−Heat jumper
settings − page 11.
E−Heat Vacation
Mode Mode Fan Cooling ElectHeating
-
Error code present? If Does outdoor unit respond to demand?
-
so, see troubleshooting/
Is it operating properly?
diagnostic section of this -
Are appropriate outputs energized in response to demand?
manual (Page 25).
-
Does zone control system energize appropriate outputs? During
Cooling? During Heating?
-
24VAC from furnace transformer to R?
-
Does furnace respond to outputs?
-
Does blower speed change as zone demand changes? If no,
does DS output vary from 0 to 25VDC?
Figure 23
Page 27
-
Line Voltage to transformer?
-
24VAC from transformer to zone
control board?
-
Are all wire connections good?
Are all wire connections correct?
Thermostat 1
W C Y G R
24
VAC
C R
W C Y G R
-
Fuses OK?
2-STAGE CON-
DENSING UNIT
Y1
Y2
O
RC
W1−Def
Equipment
RH
G
W1
W2
W3
DS
Equipment
VARIABLE SPEED
Heating Status
HARMONY IIIT SERIES
120
VAC
Y1
Y2
C
R
R
G
W1
W2
C
DS
FURNACE