4
A
B
LEAD WIRE
"B1"
ELEMENTS
CONTACTOR
(OR P2)
POWER TERMINAL BLOCK
HEATER FRONT
LEAD WIRE
"A1"
3 PHASE BLOCK
T
O
E
L
E
M
E
N
T
S
A
B
LEAD WIRE
"B1"
ELEMENTS
CONTACTOR
(OR P2)
POWER TERMINAL BLOCK
HEATER FRONT
LEAD WIRE
"A1"
3 PHASE BLOCK
T
O
E
L
E
M
E
N
T
S
FACTORY-WIRED FOR SINGLE-PHASE POWER
FIELD-WIRED FOR THREE-PHASE POWER
B
3 PHASE BLOCK
FACTORY-WIRED FOR SINGLE-PHASE POWER
C1
D
1
D
1
C
1
C
D
B
C
D
3 PHASE BLOCK
B
3 PHASE BLOCK
FIELD-WIRED FOR THREE-PHASE POWER
C1
D
1
D
1
C
1
C
D
B
C
D
3 PHASE BLOCK
Wiring Connections for Single-Phase and Three Phase Power
(HUHAA520, HUHAA524, HUHAA720, HUHAA724, HUHAA1020 and HUH HUHAA1024)
Wiring Connections for Single-Phase and Three Phase Power (HUHAA1520)
Figure 3a.
Figure 3b.
T
T
MT-1
MT-2
BLACK TO W1
RED TO R
2-STAGE
INTERNAL
THERMOSTAT
MHRT HEAT RECOVERY
THERMOSTAT OR
REMOTE FAN
SWITCH (MRFS-2)
BLACK
RED
RED
BLACK
C
R
W1
W2
F 2
F 1
G
T R
T
S
S
REMOTE SUMMER FAN
SWITCH (MRFS-1)
FAN RELAY
(FOR MRFS-2 AMD MHRT)
SUMMER
FAN
SWITCH
MT-1
MT-2
2-STAGE
INTERNAL
THERMOSTAT
BLACK
RED
RED
BLACK
P2
H2
F 1
F 2
S
REMOTE SUMMER
FAN SWITCH (MRFS-1)
OR SUMMER FAN
SWITCH MCFS (MANUAL)
P1
H1
REMOTE SUMMER FAN
SWITCH (HUHAARFS1)
FAN RELAY
FOR (HUHAARFS2 AND HUHAAHRT)
(HUHAAHRT) HEAT RECOVERY
THERMOSTAT OR REMOTE
FAN SWITCH (HUHAARFS2)
REMOTE SUMMER FAN
SWITCH (HUHAARFS-1) OR
SUMMER FAN SWITCH
HUHAAFS (MANUAL)
HUHAA MT-2
HUHAA MT-1
HUHAA MT-1
HUHAA MT-2
Figure 4. Control Terminal Board (for Heaters Without Contactors)
NOTES:
1. THIS STYLE CONTROL TERMINAL BOARD USED
WITH MODELS HUHAA320, HUHAA324,
HUHAA327, HUHAA520, HUHAA524, HUHAA527.
2. WHEN UNIT IS WIRED FOR SINGLE PHASE,
JUMPER H1 TO H2. IF SINGLE POLE THER-
MOSTAT IS USED WITH SINGLE PHASE UNIT,
CONNECT THERMOSTAT LEADS TO P1 AND H1.
3. EXTERNAL LINE VOLTAGE THERMOSTATS
SHOULD BE TREATED AS SINGLE STAGE ONLY.
T
T
MT-1
MT-2
BLACK TO W1
RED TO R
2-STAGE
INTERNAL
THERMOSTAT
MHRT HEAT RECOVERY
THERMOSTAT OR
REMOTE FAN
SWITCH (MRFS-2)
BLACK
RED
RED
BLACK
C
R
W1
W2
F 2
F 1
G
T R
T
S
S
REMOTE SUMMER FAN
SWITCH (MRFS-1)
FAN RELAY
(FOR MRFS-2 AMD MHRT)
SUMMER
FAN
SWITCH
MT-1
MT-2
2-STAGE
INTERNAL
THERMOSTAT
BLACK
RED
RED
BLACK
P2
H2
F 1
F 2
S
REMOTE SUMMER
FAN SWITCH (MRFS-1)
OR SUMMER FAN
SWITCH MCFS (MANUAL)
P1
H1
REMOTE SUMMER FAN
SWITCH (HUHAARFS1)
FAN RELAY
FOR (HUHAARFS2 AND HUHAAHRT)
(HUHAAHRT) HEAT RECOVERY
THERMOSTAT OR REMOTE
FAN SWITCH (HUHAARFS2)
REMOTE SUMMER FAN
SWITCH (HUHAARFS-1) OR
SUMMER FAN SWITCH
HUHAAFS (MANUAL)
HUHAA MT-2
HUHAA MT-1
HUHAA MT-1
HUHAA MT-2
Figure 5. Control Terminal Board (for Heaters With Contactors)
NOTES:
1. THIS STYLE CONTROL TERMINAL BOARD USED
WITH MODELS EXCEPT HUHAA320, HUHAA324,
HUHAA327, HUHAA520, HUHAA524, HUHAA527.
.2. REMOVE JUMPER W1 TO W2 WHEN 2-STAGE THER-
MOSTAT IS USED.
3. *ONLY ONE OF THESE ACCESSORIES MAY BE
INSTALLED IN A SINGLE HEATER.
4. EXTERNAL
LINE
VOLTAGE
THERMOSTATS
SHOULD BE TREATED AS SINGLE STAGE ONLY.
