Flame LED slow blink Amber flame LED - marginal flame sense

What the control is telling you

Amber flame LED blinking 1-4 times per second means a weak flame signal. Steady on = normal flame, off = no flame. See code 12.

Applies to: 802P/80MDP (802PA050-150); R95P (R95PA040-115); Rheem (-)GRC upflow and (-)GTC downflow/horizontal 90 Plus condensing gas furnaces (UT Electronic Controls 1012-925 / 1028-928 and Invensys ICC-H1MC7-01 IFC); Rheem 90RJ and 90TJ 90 Plus condensing gas furnaces (UT Electronic Controls 1012-925 or Invensys ICC-H1MC7-01 IFC, hot surface ignition)

Likely causes

• Dirty flame sensor
• Poor ground
• Reversed polarity
• R95P: twinned units out of phase (LED dim)
• Dirty or oxidized flame sense rod
• Poor ground on IFC or furnace
• L1 and Neutral reversed
• Bad wire/connection from flame rod to IFC
• Poor flame carry-over or low gas pressure
• Twinned units with transformers out of phase (flame LED dim)

Test and repair steps

1. Clean the flame sensor and check its wire to the IFC.
2. Check ground and L1/neutral polarity.
3. Check gas pressure, flame contact with the rod and flame carry-over to all burners.
4. See code 12.
5. Warning: Hazardous line voltage - disconnect power before servicing; work must be done by a trained, qualified service technician.
6. Clean the flame sense rod (sandpaper / steel wool) - recommended at the start of every heating season.
7. Check the ground on the IFC and the unit.
8. Check polarity between L1 and Neutral at the IFC and junction box.
9. Check wire continuity from the flame sense rod to its pin on the IFC connector.
10. Check that flame carries across all burners and that all burners stay lit; verify gas pressure.
11. On twinned units confirm the transformers are in phase.

Settings for these units

Filter sizes (Table 12) · Rheem 90RJ/90TJ 90 Plus

Filters are not factory-installed; they must be field supplied.

Side filter on 21 in. units: cut 3.5 in. off the filter and frame; on 24.5 in. units cut 7 in.

Minimum clearance to combustibles · Rheem 90RJ/90TJ 90 Plus

Same values for every cabinet size.

24 in. service clearance recommended in front of all furnaces.

• Filter sizes (Table 9) · Rheem (-)GRC/(-)GTC 90 Plus
• Minimum clearance to combustibles · Rheem (-)GRC/(-)GTC 90 Plus
• Clearance to combustibles (all models) · R95P
• Reduced clearance to combustibles, upflow/horizontal (Fig. 4) · Rheem/Ruud 802P / 80MDP 80% two-stage furnace (UT 1028-928 IFC)

Models that show this code

34 models in Rheem/Ruud 802P / 80MDP 80% two-stage furnace (UT 1028-928 IFC), R95P, Rheem (-)GRC/(-)GTC 90 Plus, Rheem 90RJ/90TJ 90 Plus

Other codes on the same units

• 55 Pressure switch stuck closed
• 57 Pressure switch stuck open
• 58 Water sense circuit open
• 59 Water sensed / blocked drain
• 61 Blower fault - blower not running
• 93 Internal control fault
• Flame LED off No flame sensed (troubleshooting aid)
• Flame LED rapid blink Amber flame LED - unexpected flame