Error Codes

In the event of a system failure, an error code displays and a constant tone is heard. To silence the tone, press any button.

Display

Cause

Solution

E-4 Control board overheating Turn switch to OFF position, then back to ON. If E-4 persists, the control board is getting too hot. Check the louvers on each side of the unit for obstructions
E-5 Oil overheating Turn switch to OFF position, then back to ON. If E-5 persists, the heating circuits and temperature probe should be checked.
E-6a Temperature probe open Turn switch to OFF position, then back to ON. If E-6a persists, the temperature probe should be checked.
E-6b Temperature probe shorted Turn switch to OFF position, then back to ON. If E-6b persists, the temperature probe should be checked.
E-10 High limit Reset the high limit by manually pushing up on the red reset button. If the high limit does not reset, the high limit must be replaced.
E-15 Drain switch failure Close the drain using the drain valve handle. If E-15 persists, check the drain microswitch.
E-20a Air pressure switch failure (stuck closed) Press the Timer button to try the ignition process again. If E-20a persists, check the air switch.
E-20b

Draft fan or air pressure switch failure (stuck open)

Press the Timer button to try the ignition process again. If E-20b persists, check the air switch or the blower motor.
E-20c Ignition modules not responding Press the Timer button to try the ignition process again. If E-20c persists, check the ignition module, the spark ignitor, or the I/O board.
E-20d

Pilots not lit or no flame sense

Press the timer button to try the ignition process again. If E-20d persists, check the ignition module, the I/O board, or the flame sensor.
E-31 Fan jumper wire missing Check for jumper wire on 12-pin connector and add if missing.

E-41

E-46

 Programming failure

Turn switch to OFF position, then back to OON. If error persists, try to reinitialize the control (refer to Special Program Mode). If error code persists, replace the control board.
E-47

Analog converter chip or 12-volt supply failure

Turn switch to OFF position, then back to ON. If E-47 persists, replace the I/O or PC board. If the speaker tones are quiet, it's probably an I/O board failure.
E-48 Input system error Replace the PC board.
E-54

PCB component failure

Turn switch to OFF position, then back to ON. If E-54 persists, replace the PCB.
E-70 Faulty power switch, or switch wiring. Faulty I/O board Have the power switch checked, along with its wiring. Have Input/Output board replaced if necessary.

E-70a

(C1000)

Fan switch jumper missing

Have jumper wire checked on 12-pin connect to panel.

E-70d

(C1000)

 MV jumper missing Have jumper wire checked on connectors to panel.
E-92

24-VAC fuse on I/O open

24-VAC fuse on I/O board open; check for shorted component in 24-volt circuit. (i.e., hi limit, drain switch, air switch)