User Manual
G
Green LED on
programmable
controller is
steady ON
Green LED on
programmable
controller is
OFF.
No display at
touch pad, all
indicator lights
are off.
Heaters d
o not
operate.
Is main power supply
fuse in Smart Box
™
delivering 120 VAC to
transformers?
No
Is 120 VAC
delivered to
Smart Box
™
?
Yes
Check breakers in building.
Check power cord for tight
connections and continuity.
Check power outlet for
defects, corrosion, etc.
No
Replace the fuse. Verify
by checking voltage to
and from fuse or check
continuity.
Is upper
transformer
receiving 120
VAC from main
power fuse?
No
Yes
Problem 2
Defective electrical wire or
connection. Repair or replace as
needed.
Verify 24 VAC between the two
yellow leads, (Terminals 10 and 6)
of the transformer. If absent,
replace the transformer.
Yes
Is
upper transformer
delivering 24 VAC to
programmable
controller?
No
Yes
20
Cycle the power to the
Smart Box
™
OFF and then
ON. If the LED remains
steady ON, replace the
controller.
Problem 1
Is touch pad receiving
18 VDC from
controller?
No
Check across brown wires at touch pad. If 18
VDC is absent, trace the wires back to the
controller.
Check for 18VDC at the programmable
controller terminals 5 and 6 (brown). If
present at the programmable controller,
repair or replace wiring between the touch
pad and the programmable controller. If
absent, replace the programmable controller.