2 flashes = Thermopile voltage low. The voltage generated by the thermopile (or thermocouple on standing-pilot units) is below the threshold needed to keep the gas valve open. Common on State Select and ProLine atmospheric gas units.
Diagnostic sequence
1. Clean the intake screen (#1 cause)
FVIR-equipped State units have a fine mesh intake screen at the base of the unit. When clogged with lint and dust, combustion air is restricted, pilot flame weakens, and thermopile voltage drops. Clean the screen by vacuuming from below. This resolves 50% of chronic 2-flash issues on units 5+ years old.
2. Inspect the pilot flame
Light or relight the pilot per instructions. Observe the flame:
- Pilot flame should be steady blue, enveloping the top ⅓ of the thermocouple tip
- Weak yellow or wavering flame = inadequate gas supply
- Flame missing the thermocouple = pilot orifice or pilot bracket issue
3. Clean the pilot tube
Spider webs or dust in the small pilot tube restrict gas flow. Use compressed air to clear (gas off, of course).
4. Replace the thermocouple
If above steps don't restore strong pilot flame, replace the thermocouple. See State thermocouple page. $15-25 part, 45 min DIY.
5. Verify gas supply pressure
Low incoming gas pressure (typically below 4" WC NG) prevents proper pilot. Have a plumber test pressure with a manometer.
Reset
- Address the suspected cause
- Cycle gas valve (off → pilot → on)
- Relight pilot if needed; hold gas button 60 seconds after pilot lights
- Monitor LED — 1 flash = restored; 2 flashes = issue still active
Bottom line
Most 2-flash cases resolve with intake screen cleaning + thermocouple replacement. Cheap fixes that 90% of homeowners can DIY.