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OJ Troubleshooting, GFCI Flash codes, Specs, and Theory Of Operation


What are troubleshooting procedures for the OJ thermostats?  How do the heating cycles work?

See attached sheet.

Here are the GFCI Flash Codes:

The red LED on the right of the thermostat can indicate four different GFCI/EGFPD
1. LED off – NORMAL state.
2. LED flashing slowly (once every two seconds) – TRIGGERED state. Try pressing
the “Standby/Reset” button on side of unit to reset the GFCI/EGFPD.
3. LED flashing quickly (five flashes per second) – ERROR state. Try switching the
power off and then back on again. If the thermostat re-enters ERROR state, either
the wiring is wrong (a ground-neutral short exists) or the unit is defective and
must be replaced.
4. LED lit constantly – Internal microprocessor malfunction or abnormal hardware
fault! Try switching the thermostat off and then back on again. If the LED still
lights constantly, the GFCI/EGFPD is defective and the thermostat must be
Note: The LED lights up briefly without flashing during every power-up.


When thermostat calls for heat it closes a contact between A & B. There are no voltage being sent to a power module.

Written by Scott Rosenbaum
Posted on
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