Wiring Diagram - Mr. Heater Big MAXX MHU125 Operating Instructions And Owner's Manual

MAXIMUM LOAD NOT TO EXCEED
1
20VA AT 24V, CLASS 2
(2) S47 USED IN
2
75, 80 AND 125 ONLY
NOTE -
IF ANY WIRE IN THIS APPLIANCE IS REPLACED,
IT MUST BE REPLACED WITH WIRE OF LIKE SIZE,
RATING AND INSULATION THICKNESS.
WARNING -
ELECTRIC SHOCK HAZARD CAN CAUSE INJURY
OR DEATH. UNIT MUST BE GROUNDED IN
ACCORDANCE WITH NATIONAL AND LOCAL
CODES.
DISCONNECT ALL POWER BEFORE SERVICING!
DESCRIPTION
KEY COMPONENT
A3 CONTROL BOARD (PCB)
B3 MOTOR CIRCULATION
B6 MOTOR-COMBUSTION AIR INDUCER
C4 CAPACITOR-BLOWER MOTOR 1
C5 CAPACITOR-INDUCED DRAFT MOTOR
DL36 RELAY-RELAY (N/A TO THESE MODELS)
GV1 VALVE-GAS
S10 SWITCH-PRIMARY GAS
S18 SWITCH-COMB AIR BLOWER
S47 SWITCH-FLAME ROLLOUT
T1 TRANSFORMER-CONTROL
BLACK
WHITE
CHASSIS GROUND
L1
CONNECT CHASSIS
GROUND TO
EARTH GROUND
CAPACITOR USED IN 125 ONLY

WIRING DIAGRAM

FLAME
SENSOR
S18
(1)S47 (2)S47 ORANGE
2
BROWN
SPARK
ELECTRODE
GV1
CMB
A3
BLWR
ACC ACC
B6 C5
CAPACITOR USED IN
B3 C4
75, 80 AND 125 ONLY
LADDER DIAGRAM
White
L1 Black
(HOT)
White
N
(NEUTRAL)
EQUIPMENT
GROUND
Flame
Sensor
Air Switch
Compact Unit / Utility Heater
R
1
G
24VAC
HOT
W
FLAME
C
1 TO 6
P1 ON BOARD
BROWN
PRES. SW.
5
RETURN
RED
PRES. SW.
2
OUT
R
HIGH LIMIT
1
SW. RETURN
G
S10
BLUE
HIGH LIMIT
6
SWITCH
W
OUT
C
BLUE
GAS VLV
3
RETURN
YELLOW
GAS VLV
4
OUT
GND
A3
LINE VOLTAGE FIELD INSTALLED
ANALOG THERMOSTAT WIRING
DIGITAL / WiFi THERMOSTAT WIRING
IT IS RECOMMENDED TO USE 18AWG WIRE WHEN INSTALLING THE
THERMOSTAT. CONNECT ANALOG THERMOSTAT WIRING TO TERMINALS
'R' AND 'W' AS ILLUSTRATED ON THE SCHEMATIC DIAGRAM OR
CONNECT A DIGITAL/WiFi THERMOSTAT TO 'R' 'W' 'C' AS ILLUSTRATED.
NOTE: THERMOSTAT TERMINAL CONNECTIONS ARE MOUNTED ON THE
BACK PANEL OF THE HEATER.
EXTERNAL THERMOSTAT TERMINAL STRIP WANING: DO NOT CONNECT
LINE POWER TO THE THERMOSTAT TERMINAL STRIP.
Fan Black
Combustion Blower
White
Transformer
120 V
24V
Orange
Flame Rollout
White
Switch
Blue
Yellow
Blue
Flame Rollout
Switch
Red
Gas Valve
Igniter
13
Operating Instructions and Owner's Manual
24 Vac POWER
OPTIONAL FAN CONTROL
HEAT 1
COMMON
Red
White
Blue/Black
OPTIONAL THERMOSTAT INSTALLATION
ACB COOL
ACB HEAT
ACC LOW
ACC
ACC
Black
HTG ACC
CWB BLWR
Black
L1
Blue
24 VAC (HOT)
24 V POWER (R)
FLAME SENSOR
PSW RTN
MAN BLOWER (G)
PSW OUT HEAT 1 (W1)
HIL RTN
HIL OUT
SPK ELE
VLV RTN
VLV OUT
GND PRO THER
GND
24 V (COMM) (C)
Equipment Ground
ANALOG
DIGITAL / WiFi
THERMOSTAT