MORTEX PRODUCTS INC 501 TERMINAL RD FORT WORTH, TX 76106 Page 19
Integrated Control Board Diagnostic Codes
1 Flash - System Lockout. Ignition Retries Exceeded
Failure to sense ame is often caused by carbon deposits on the
ame sensor, a disconnected or shorted ame sensor lead, or a
poorly grounded furnace. Carbon deposits can be cleaned with
emery cloth or steel wool. Verify the sensor is not contacting the
burner and is located in a good position to sense ame.
The ignitor must be positioned to light the gas when the valve
opens. If the ignitor has been replaced, verify the position has not
changed.
Check sensor lead for shorting and verify the furnace is grounded
properly. Verify the gas supply to gas valve, the gas valve is in the
“ON” position and is furnace lighting properly. Verify ame engulfs
the ame sensor during ignition attempts and gas pressures are
correct.
2 Flashes - Pressure Switch Stuck Closed
Check the pressure switch function and verify the combustion air
motor is o.
3 Flashes - Pressure Switch Stuck Open
Check pressure switch function and tubing. Verify the combustion
air motor is running and pulling sucient vacuum to engage
pressure switch.
4 Flashes - Open Limit Switch
Verify continuity through the main limit switch located in the
control box and the manual reset limit switch located next to the
blower.
5 Flashes - Flame Sensed More Than 4.24 seconds After Gas
Valve is De-Energized.
Verify the gas valve is opening and shutting down properly. Flame
in burner assembly should extinguish promptly at the end of the
cycle. Check orice and gas pressure.
6 Flashes – Flame Rollout Switch Open
The furnace does not have a rollout switch. The 12 pin plug has a
purple jumper wire in place of the switch. Check the jumper wire
to be sure it is securely inserted into the plug.
7 Flashes - Low Flame Sense Signal
Low ame sense current is often caused by carbon deposits on
the ame sensor, a poorly grounded furnace or a mis-aligned
ame sense probe. Carbon deposits can be cleaned with emery
cloth or steel wool. Check furnace and control board grounding.
Verify the ame sensor is located in the ame. The minimum
current for proper operation is 0.5 DC micro amps.
8 Flashes - Ignitor Relay Fault
The ignitor relay on the control board has failed. Replace the
control board.
9 Flashes - Twinning Fault
If twinning is used, verify eld installed wiring is connected
correctly. Verify both control boards are the same model.
10 Flashes - Open Fuse
Verify the 3 amp fuse on the control board has opened. Verify
there are no shorted circuits and replace the fuse.
11 Flashes - Ignitor Open (External to the Control)
Verify the ignitor is operating correctly and has not failed by
checking to see if it glows during the ignition cycle. If it does not
glow during the ignition cycle, replace the ignitor.
12 Flashes - Combustion Air Blower Relay Error
The relay built into the control board has failed. Replace the
control board.
Rapid Flash - Reverse Polarity
Reverse the incoming power wires connected to the control
board “L1” and “Neutral” terminals.
Continuous On - Normal Operation - No Fault
O - Control Failure / No Power / Internal Fault / IEQ Loss
Verify there is 115 VAC across the control board “L1” and “Neutral”
terminals. Replace control if power is at the control and the LED is
o.
Fault Code Retrieval: The control will ash the last 5 fault codes
that occurred when the push button is pressed to give the service
tech more troubleshooting capability. The last fault code is
ashed rst.
Flame Sense Current
Normal ame sense current is approximately 2.8 micro amps DC.
Minimum ame sense current threshold is 0.5 micro amps DC.
Checking and Adjusting the Gas Inlet Pressure
1. Follow the procedure for “Shutting The Furnace O” located
in Section 3: Startup and Shutdown Instructions in the User
Information Manual.
2. Turn the switch on the gas valve to the “OFF” position. Refer to
Figure 18 for switch location.
3. Turn o the gas supply at the ball valve or gas cock upstream
of the gas valve.
4. Locate the furnace gas control.
5. Find the gas valve pressure ports labeled “IN P” which is the
inlet or line pressure tap (See Figure 18) and remove the
pressure port cap.
6. Use a 3/32” (2.4 mm) Allen wrench to loosen the “IN P” port set
screw by turning it counter clockwise one (1) turn only.
DO NOT REMOVE THE SET SCREW.
7. Connect the 1/8” (3.175 mm) ID exible tubing to the positive
side of the “U” tube monometer or pressure gauge and the
other end of the tubing to the port marked “IN P” on the gas
valve as shown in Figure 19.
8. Turn the ON/OFF switch on the gas control to the “ON” position.
9. Follow the “Starting the Furnace” instructions located in
Section 3: Startup and Shutdown Instructions in the User
Information Manual to properly start the furnace.
10. Check the line pressure. If the pressure is at the pressure
specied in Table 1, go to step 10. If the pressure is not at the
correct pressure, adjust the pressure at the regulator upstream
of the gas valve while the furnace is operating until the correct
pressure is measured at the gas valve pressure port.
11. Follow the procedure to “Shutting the Furnace O”
instructions located in Section 3: Startup and Shutdown
Instructions in the User Information Manual.
12. Turn the switch on the gas valve to the “OFF” position.
13. Turn o the gas supply at the ball valve or gas cock upstream
of the gas valve.
14. Remove the “U” tube monometer or pressure gauge from “IN
P” and tighten the set screw. Replace the pressure port cap.
15. After the correct inlet pressure has been conrmed, follow the
instructions on the next page for checking the manifold
pressure.
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