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7-13
7.10 Interface Board Diagnostic Chart
The following diagram and charts provide ten quick system checks that can be performed using only
a multimeter.
Meter Setting Test Pin Pin Results
12 VAC Power 50 VAC Scale 3 of J2 1 of J2 12-16 VAC
24 VAC Power 50 VAC Scale 2 of J2 Chassis 24-30 VAC
*Probe Resistance (RH) R X 1000 OHMS 11 of J2 10 of J2 See Chart
*Probe Resistance (LH) R X 1000 OHMS 1 of J1 2 of J1 See Chart
High-Limit Continuity (RH) R X 1 OHMS 9 of J2 6 of J2 0 - OHMS
High-Limit Continuity (LH) R X 1 OHMS 6 of J1 9 of J1 0 - OHMS
Latch Contactor Coil (RH) R X 1 OHMS 8 of J2 Chassis 3-10 OHMS
Latch Contactor Coil (LH) R X 1 OHMS 5 of J1 Chassis 3-10 OHMS
Heat Contactor Coil (RH) R X 1 OHMS 7 of J2 Chassis 18-25 OHMS
Heat Contactor Coil (LH) R X 1 OHMS 4 of J1 Chassis 18-25 OHMS
* Disconnect 15-Pin harness from the computer/controller before testing the probe circuit.
Diagnostic LED Legend
CMP indicates power from 12V transformer
24 indicates power from 24V transformer
HI (RH) indicates output (closed) from right
latch relay
HI (LH) indicates output (closed) from left
latch relay
HT (RH) indicates output from right heat
relay
HT (LH) indicates output from left heat relay
AL (RH) indicates output (open) from right
latch relay
AL (LH) indicates output (open) from left
latch relay
3
2
1
6
5
4
9
8
7
12
11
10
3
2
1
6
5
4
9
8
7
12
11
10
K1
K2
K3 K4
Left
Latch
Relay
Right
Latch
Relay
Left
Heat
Relay
Right
Heat
Relay
1
23
4
5
6
8
7
9
10
11
12
13
14
15
J3
J1
J2
AL HI
HT
CMP
24V
HT
HI
AL
Diagostic LEDs
Test Points
J1 Left J2 Right
NOTE – When testing the test points on J1
and J2 test use the illustration above dis-
regarding any silkscreened numbers on
the board depicting the location of Pin 1.
Pin 1 is located in the bottom right corner of
Both J1 and J2. These test points are ONLY
for RE Series boards with J1 and J2 plugs on
the front of the board.
PN 106-6811