4 flashes Low flame signal

What the control is telling you

Flame signal is weak. The control keeps running but warns that the flame sensor needs attention.

Applies to: EL195UHNE furnaces with ignition control 103217-03 or 107163-01 (red LED)

Likely causes

• Oxidized or dirty flame sensor
• Sensor bent away from flame
• Poor ground
• Incorrect combustion (manifold/air orifice)

Test and repair steps

1. Use the recall button / meter to read flame current. Read flame signal: normal 2.6 uA or more, low 2.5 uA or less, drop-out 1.1 uA (Table 7). Note: the troubleshooting flowchart uses 1.5 uA as the low limit.
2. Warning: Shut off power and gas before removing the sensor (top of the air gas plenum).
3. Clean the sensor rod and check its position; replace if damaged.
4. Check the burner ground and Check ground at the control: AC volts between line neutral and the C terminal should be about 0.3 V (2 V max) at idle, 0.75 V (5 V max) with inducer/ignitor on, under 2 V (10 V max) with blower on; line hot to neutral should be 97-132 VAC.
5. Check manifold pressure and the air orifice size if the flame is poor.

Settings for these units

Filter sizes (filter rack kits) · Lennox EL195UHNE

Filters are field supplied; check monthly.

100NE60C over 1800 cfm with single side return needs a 20 x 25 x 1 filter via return air base and transition.

Models that show this code

4 models in Lennox EL195UHNE

Other codes on the same units

• 1 flash Line voltage polarity reversed
• 2 flashes Improper earth ground
• 3 flashes Burner failed to light or lost flame
• 5 flashes Watchguard - ignition retries/recycles exceeded
• 7 flashes Primary or secondary limit open
• 8 flashes Rollout switch open
• 9 flashes Pressure switch stays open or drops out on a heat call
• 10 flashes Watchguard - pressure switch opened 5 times in one heat demand