Majestic 33LDVRRN pilot burning, no gas to burner

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New Member
Jan 31, 2022
Majestic 33LDVRRN Rear Direct Vent, switch-operated, FK24 fan, natural gas. installed 2005.
Used very little (maybe 10days/yr), and unused/pilot off approx 7mos/yr.
17 years of flawless operation -until now.
Fireplace started normally, then the fan. After 20-30" noticed the burner out (pilot still lit and fan ran until unit cooled).
Now the burner won't light.
Troubleshoot table in manual offers (4) possible causes:
- Wall switch or wires defective unlikely since the switch had just lit the burner.
- Plugged burner orifice -unlikely since the burner was operating normally(?)
- Thermopile may not be generating sufficient millivoltage
- Defective automatic valve operator

From manual, under Maintenance:
Most burner/control system components may require only an occasional checkup and cleaning and some may require adjustment.
Maintenance: remove logs and vacuum burner cmporartment especially around orifice primary air openings.
Inspect pilot, brush or blow away any dust or lint.
Verify pilot and burner flame are steady, not lifting/floating -verified pilot flame appears OK
Verify top 3/8" to 1/2" of thermopile engulfed in pilot flame -verified top 1/2" of thermopile is engulfed in pilot flame.

Admit that firebox never vacuumed, therefore plan to do that. What is acceptable timeline for "occasional cleaning"?
At 17yrs old, are parts like Thermopile P/N 51827 and "automatic valve operator" (Valve SIT 820 -RN P/N 52677?) due for replacement?

Appreciate advice regarding problems to focus troubleshooting on, and/or YouTube videos and other sources of info that may help.
Thanks for your time!


Full Time RVer
Staff member
Dec 2, 2008
Wherever we're parked
Get a multimeter & read the millivolt output of the thermopile.
It should be 525+/- 25 with ONLY the pilot lit...
If it's less than that or starts high & drops, it's time to replace it.
Universal thermopiles (aka millivolt generators) are available at
most hardware stores for about $50-$60...
Gas heating appliances should be cleaned and tuned every 2 - 3 years.
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New Member
Jan 31, 2022
To close the loop for this troubleshoot/fix:
Thermopile tested OK (.645V off, and .386V on).
Then removed main burner switch to remove/connect wires to determine if switch bad.
Found upper terminal screw loose -tightened it down without removing/direct-connecting the wires.
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