1.10.2 Troubleshooting the 24 VAC Circuit in Units with Interface Boards
Verify that the drain
valve is fully closed, then
turn the controller on.
Which LEDs are lit?
GV LED (with
None24V LED onlyor without other LEDs)
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Is 24VAC |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| |||||
present on IFB 24V |
|
|
|
|
|
| Yes |
|
|
|
|
|
|
|
|
|
|
| ||||||
terminals? |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| |||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| ||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| No |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Probable cause |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| |||||
is a failed |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| |||||
transformer. |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| |||||
Probable cause |
|
|
|
|
|
|
|
|
| Is 24VAC |
|
|
|
|
| |||||||||
is a failed interface |
|
| No |
|
|
|
|
|
| present on J1 |
|
|
|
|
| |||||||||
|
|
|
|
|
|
|
|
|
|
|
|
| ||||||||||||
board. |
|
|
|
|
|
|
|
|
| Pin 6? |
|
|
|
|
| |||||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
| |||||||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| Yes |
|
|
|
|
|
|
| |
Attempt to light pilot. If |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| |||||
the pilot will not light, see |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| ||||
| No |
|
|
|
|
| Is pilot lit? |
|
|
|
|
| ||||||||||||
Troubleshooting the Gas |
|
|
|
|
|
|
|
|
|
|
| |||||||||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| ||||||
Valve on Page |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| |||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| ||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| Yes |
|
|
|
|
|
|
| |
If unit has a drain safety switch, |
|
|
|
|
|
|
|
|
| Is 24VAC |
|
|
|
|
| |||||||||
probable cause is open or failed |
|
|
|
|
|
|
|
|
|
|
|
|
|
| ||||||||||
switch. If not, probable cause is loose |
|
| No |
|
|
|
| present on Pin 20 of |
|
|
|
|
| |||||||||||
|
|
|
|
|
|
|
|
|
|
| ||||||||||||||
or missing jumper between Pins 10 |
|
|
|
|
|
|
|
|
| terminal block? |
|
|
|
|
| |||||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
| |||||||||||
and 19 of |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| |||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| ||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| Yes |
|
|
|
|
|
|
| |
Probable cause is failed |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| |||||
|
|
|
|
|
|
|
|
| Is 24VAC |
|
|
| Problem is with gas valve. | |||||||||||
wiring between |
|
|
|
|
|
|
|
|
|
|
|
|
| |||||||||||
| No |
|
|
|
|
| present at the gas |
|
| Yes |
| See Troubleshooting the | ||||||||||||
terminal block and gas |
|
|
|
|
|
|
|
| ||||||||||||||||
|
|
|
|
|
|
|
|
| valve? |
|
|
| Gas Valve on Page | |||||||||||
|
|
|
|
|
|
|
|
|
|
|
| |||||||||||||
valve. |
|
|
|
|
|
|
|
|
|
|
|
| ||||||||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|