Lennox EL280UHE Series Service Literature page 17

P49
5
4
3
2
1
N
G
L
C
P48
Test 1
Turn on power to unit. Check for 120 volts across terminals
"L" and "N" on input plug P48. If voltage is present continue
stream of plug P48 and proceed to test 3.
P49
5
4
3
2
1
N
G
L
C
P48
Test 2
Switch thermostat to CONTINUOUS FAN MODE. Check for
24 volts across terminal "C" on input plug P48and speed tap
used for continuous fan. (1, 2, 3, 4 or 5) on input plug P49. If
24 volts is not present problem may be up stream of plug P49.
Proceed to test 4.
Multi−Meter
(set to VAC)
12 12
0 0
Test 3 (if necessary)
Check for 120 volts across terminals "L1" and "Neutrals" on
the integrated control. If voltage is present, problem is with
the harness. If voltage is not present problem may be may
be with the integrated control.
Multi−Meter
(set to VAC)
24
Test 4 (if necessary)
ent, problem is with the harness. If voltage is not present
problem may be may be with the integrated control
Figure 8
Page 17
Multi−Meter
(set to VAC)
12 12
0 0
Multi−Meter
(set to VAC)
24