Lennox LGH240H

Page 118
F/A
A63
K27
A
B
A2
Y1
Y2
Y3
K27-1
1
7
TO PROVIDE THREE COMPRESSOR STAGES.
REQUIRES 3HEAT, 3COOLTHERMOSTAT
AND K27 RELAY.
K55
B
A
K55-1
7
5
2
S86
J264A
1
2
J262B
5
6
RT6
RT6
RT16
3
A172
J253
A173
P255
P255
J250
J252
P250 P252
P253
J255
1 6 3 4
J255
2
S42
1
S149
J262C
10
11
12
P297
P298
J298A
1
2
B
3
4
C
5
6
7
P299
D
8
9
10
J299A
1
2
3
B
4
5
C
6
7
10
J100
1
4
P100
J99
1
4
P99
D
8
9
J297A
1
2
B
3
4
5
6
7
8
C
9
10
A91
VO
VIN
GND
J299A
1
2
J297A
7
6
2
R
OCP
C
G
W1
W2
Y1
Y2
24 V COMMON
24 V POWER
4
S52
S27
J264C
6
7
8
S135
5
W1
W2
P262
P262P264
C
R
C
AI-1
HUM
TMP
DO-1
C
DO-2
DI-1
R
C
DI-2
R
DI-3
R
DI-4
C
A55
P304
6
7
A171
J251
P251
J261
1
2
3
4
8
R
OCP
C
G
W1
W2
Y1
Y2
TO R
TO G
TO Y1
TO PROVIDESUPERMARKETREHEATSCHEME
USE S86 DEHUMIDISTAT AND K55.
ALL OTHER THERMOSTAT
SIGNALS REMAIN CONNECTED
AS SHOWN ON THE RIGHT.
TO M2 THERMOSTAT INPUTS
2
2
ELECTRONIC OR ELECTROMECHANICAL THERMOSTAT
POWER:
1. Terminal block P297 on the A55 Unit Controller energizes the thermostat components with 24VAC.
OPERATION:
al N.O. air flow switch S52 (indicates no air [i.e. broken belt] system shuts down).
3. The A55 receives data from the supply and return smoke detectors A171 and A172, blower motor overload
relay S42, discharge sensor RT6 and return air sensor RT16.
4. The A55 receives data from the electronic thermostat A2 (Y1, Y2, W1, W2, G, OCP) and the CO
2
sensor (if
economizer is used) via terminal block P297. A55 energizes the appropriate components.
Lennox Commercial
ACCESSORIES
REV. 3.0
1
3
P298-8 (DO-1) IS SERVICE RELAY OUTPUT (24VAC)
IF USED CONNECT TO AN INDICATOR LIGHT
FOR MOTORS WITH S42 AND S135 EXTERNAL OVERLOAD LESS
INVERTER, SEE INVERTER WITH BY PASS FOR S42 HOOK UP
REMOTE LOCATION OF RT6
4
USES86 DEHUMIDISTAT ANDK55 FOR OPTIONAL
SUPERMARKET REHEAT SCHEME, M2 PARAMETERS NEED TO BE
MODIFIED UNDERTHE SETTINGSMENUORVIA UC SOFTWARE
FOR SIMULTANEOUS HEATING AND COOLING.
2
THERMOSTAT HOOKUP FOR PROGRAMMABLE CONFIGURATION
OF THE M2 BOARD (A55).
5
6
M2 SETTINGS MUST BE MODIFIED WHEN A42, S42, S52, S135
OR S149 ARE INSTALLED
7
A42 USED ON 036 THROUGH 72 UNITS ONLY
CONNECT A172 SENSOR TO J261 ON SUPPLY AIR SMOKE
DETECTOR ONLY
8
1
2
4
3
3
4
3