voltage applied to low-voltage circuit, or a direct secondary short.
When there is a high current draw on transformer, it is most likely
because transformer has been shorted or system is trying to draw
more VA than transformer rating allows. When fuse blows because
of high voltage, the system has mixed high- and low-voltage
signals.
1. Check wiring of sequencers/relays as shown in Fig. 4 and 5.
Be sure transformer is not shorting out because thermostat
wires are miswired.
2. Check wiring of sequencers/relays as shown in Fig. 4 and 5.
Be sure low-voltage and high-voltage wiring is correct.
3. Check VA draw on transformer. If VA draw is more than
VA rating of transformer, fuse will blow. If this is the case,
replace transformer with one that has a higher VA rating
and meets system specifications.
D.
If Fan Runs Continuously:
1. If PCB has no low-voltage power, check blue and black fan
leads. These may be switched at sequencer/relay.
2. If PCB has low-voltage power, check fan relay to see if it is
opening and closing. It may be stuck in the normally-closed
position due to debris in relay.
Fig. 4—Wiring Diagram of Sequencer Heater
A94346
1.
USE COPPER WIRE (75°C MIN) ONLY BETWEEN DISCONNECT SWITCH AND UNIT.
2.
TO BE WIRED IN ACCORDANCE WITH NEC AND LOCAL CODES.
3.
TRANSFORMER PRIMARY LEADS, BLUE 208V, RED 230V.
4.
IF ANY OF THE ORIGINAL WIRE, AS SUPPLIED, MUST BE REPLACED,
USE THE SAME OR EQUIVALENT TYPE WIRE.
5.
REPLACE LOW VOLTAGE FUSE WITH NO GREATER THAN 5 AMP FUSE.
6.
20KW HEATER USES ONE DOUBLE POLE LS ON MIDDLE TOP ELEMENT.
7.
18, 24 AND 30KW HEATERS USE DOUBLE POLE LIMIT SWITCHES.
8.
LARGEST HEATERS ARE SHOWN, SMALLER HEATERS WILL HAVE FEWER ELEMENTS AND
COMPONENTS.
9.
1 PHASE HEATERS ARE SHOWN WIRED FOR SINGLE SUPPLY CIRCUIT.
10. USE 60 AMP CLASS K FUSES ONLY, FOR REPLACEMENT.
11. (3) SPEED MOTOR SHOWN. OPTIONAL (2) SPEED MOTOR USES HI (BLK) AND LOW
(BLU OR RED).
12. CONNECT R TO R, G TO G, ETC., SEE OUTDOOR INSTRUCTION FOR DETAILS.
13. IF WIRE CRIMP IS REMOVED AN EMERGENCY HEAT RELAY IS REQUIRED.
(SEE OUTDOOR-THERMOSTAT INSTRUCTIONS)
THIS COMPARTMENT MUST BE CLOSED EXCEPT FOR SERVICING
CAUTION:
ATTENTION:
NOT SUITABLE FOR USE ON SYSTEMS EXCEEDING
150V TO GROUND
BLOWER MOTOR
ROTATION
CAP
COM
F
FM
FR
FU
GND
HVTB
HTR
CAPACITOR
COMMON
LOW VOLTAGE FUSE
FAN MOTOR
FIELD POWER WIRING
PCB FAN RELAY
LINE FUSE
EQUIPMENT GROUND
HIGH VOLTAGE TERM BLOCK
HEATER
LS
PCB
SEQ
TRAN
RECP
CB
LEGEND
321214-101 REV. C
30KW 1PH SCHEMATIC DIAGRAM
FIELD POWER WIRING
DISCONNECT PER NEC
SEE RATING PLATE
FOR VOLTS & HERTZ
GND
HTR6 BLK
12
LS6
YEL
FU6
BLK
FU5
11
YEL
BLK
L2
L1
HTR5 BLK
10
LS5
9
SEQ 3
BLK
HTR4 BLK
8
YEL LS4
YEL
BLK
7
YEL
BLK
HTR3 BLK
6
LS3
5
SEQ 2
BLK
HTR2 BLK
4
YEL
LS2
YEL
BLK
3
YEL
BLK
HTR1
BLK
2
LS1
1
SEQ 1
BLK
LIMIT SWITCH
MARKED TERMINAL
PLUG AND RECEPTACLE
PRINTED CIRCUIT BOARD
SEQUENCER
TRANSFORMER
UNMARKED TERMINAL
RECEPTACLE
CIRCUIT BREAKER
BLK
BLU
YEL
YEL
SEE NOTE #1
NOTES:
7
9
9
11 7
11
3
2
6 1
2
3
1
6
4
4
GRY
OUTDOOR
UNIT
WHT
GR
Y
G
RED
BRN
E
W3
W2
W2
C
BRN
INDOOR
THERMOSTAT
RE
D
WHT
VI
O
BR
N
RECP
PLUG
F
1
SPT
G
PCB
BLK
C
T
R
FR
BLU
BLK
230V
208V
YEL
BRN
YEL
YEL
YEL-COM
CA
P
BRN
FM
BRN
GRN/YEL-GND
BLK-HI
BLU-MED
RED-LO
BRN
RED
TRAN
CO
M
RED
GRAY
VIO
ORN
BRN
BLU
BLK
SEQ1
SEQ3
SEQ2
CB/FU3
CB/FU1
CB/FU4
CB/FU2
HVTB
NO
NC
9
11
7
2
3
1
6
4
208/240VAC
24VAC
24VAC
PLUG
2
3
1
6
4
9
11
7
L1
L2
FIELD POWER WIRING
FIELD
POWER
WIRING
BLK
YEL
HTR6 BLK
12
LS6
YEL
FU6
FU5
11
YEL
BLK
HTR5 BLK
10
LS5
9
SEQ 3
BLK
HTR4 BLK
8
YEL LS4
YEL
7
BLK
HTR3 BLK
6
LS3
5
SEQ 2
BLK
HTR2 BLK
4
YEL
LS2
YEL
3
BLK
HTR1 BLK
2
LS1
1
SEQ 1
BLK
YEL
YEL
CB/FU3
CB/FU1
CB/FU4
CB/FU2
FIELD POWER WIRING
DISCONNECT PER NEC
SEE RATING PLATE FOR VOLTS & HERTZ
GND
BLK
L2
L1
SEE NOTE #1
HVTB
L3
VIO
ORN
SEQ1
9
11
7
2
3
RED
PLUG
BRN
GRAY
BRN
SEQ3
SEQ2
1
6
4
208/240VAC
24VAC
24VAC
30KW 3PH SCHEMATIC DIAGRAM
RESP
Y
E
L
BLK
BLK
COOLING CONTROL ONLY
SEE NOTE #13
R
BARRIER
SEE NOTE #12
BL
U
—7—
