6 Ignition proving failure

What the control is telling you

No flame sensed during trial for ignition. Control retries 3 more times before 6+1 lockout. If flame is lost during blower on-delay, blower runs for the off-delay.

Applies to: ICP F9MAE / G9MAE modulating variable-speed condensing gas furnaces (060, 080, 100, 120 kBtu/h)

Likely causes

• Gas turned off at valve or manual shut-off
• GREEN/YELLOW ground wire not connected to sheet metal
• Flame sensor grounded, dirty or faulty
• Igniter or igniter harness failure
• No 24 V to gas valve / valve not opening
• Low inlet gas pressure, poor carryover, rough ignition, wrong firing rate, air leak around igniter bracket

Test and repair steps

1. Check manual gas shut-off and gas valve switch are ON.
2. Make sure the GREEN/YELLOW wire is connected to furnace sheet metal and the flame sensor is not grounded.
3. Run component test remove R, reset power, SW1-6 ON. Igniter must glow orange/white within the 15-second warm-up. If not, check 115 V between pin 3 and NEUTRAL-L2 for 15 s: present = check harness/igniter (cold 40-70 ohms), absent = replace control.
4. Reconnect R, call for heat check 24 V at gas valve BLUE and GREEN/YELLOW wires; no 24 V = check connections, then replace control; 24 V but no gas = check all valves on, replace valve.
5. Check flame current during trial for ignition: below 0.5 DC microamps = clean sensor with fine steel wool; nominal is 4.0-6.0 microamps; replace sensor if still low.
6. If burners drop out only at low fire, test at maximum heat, check manifold pressure, burner carryover and sensor position.
7. Check inlet gas pressure 4.5-13.6 in. w.c. (natural gas) and air leaks around the igniter bracket.