BURNER FLAME ADJUSTMENT
For Dearborn Model DRC Vent-Free Heaters

Your heater has been factory tested and adjusted. Due to variations in heating values and gas pressures, it may be necessary to make an adjustment to the burner air shutter setting. Figure 1 shows the correct flame characteristics and required adjustments. A small hard blue flame or a flame blowing off the burner ports or lighting back at the burner orifice indicates too much primary air and the air shutter should be closed. A soft, blurred or yellow tipped flame indicates lack of primary air and the air shutter should be opened.

1. Light the burner.
2. After the burner has been in operation for 3 minutes or more, observe the burner flame, Figure 1, and make the air shutter adjustment, if needed.
3. Visually check the burner flame periodically. See Figure 1. Any change in the burner flame from that obtained in Step 2 above may indicate a dirty burner or burner compartment. Turn the gas off at the line cut-off valve, open the burner access door and allow the heater to completely cool. Clean the burner area with a vacuum cleaner attachment.
4. Once each year, the burner may need cleaning. This can be done with a vacuum cleaner attachment or bottle brush. Clean burner area, burner air intake, air shutter and burner ports with a brush or blow them out with a vacuum cleaner or tire pump. See Figure 1.
5. We strongly recommend having a qualified service agency inspect the unit for proper operation before the start of each heating season.
6. The orifice spud supplied for the burner has been drilled to specified gas characteristics to provide proper operation and the required gas input at the manifold pressure shown on the name plate.

• Cause: Space to be heated too large.
  Remedy: Install an additional or larger heater.
• Cause: Insufficient gas input
  Remedy: Check with dealer. Orifice may be undersized.
• Cause: Loss of heated air to outside through fireplace.
  Remedy: Install damper in fireplace.
• Cause: Loss of heated air to outside through ventilator fan.
  Remedy: Reduce air flow through ventilator fan. Install damper.

B. Excessive Heat

• Cause: Space to be heated too small.
  Remedy: Install smaller heater.
• Cause: Excessive gas input
  Remedy: Orifice may be oversized.

C. Main Burner Flame Lazy and Yellow (Also cause of combustion odors)

• Cause: Gas input too high or not corrected for high altitude.
  Remedy: Check for proper orifice size.
• Cause: Dust, lint or dirt in or around burner and air shutter.
  Remedy: See cleaning instructions.
• Cause: Air shutter not properly adjusted.
  Remedy: See adjustment instructions.

• Cause: Pilot burner not in proper alignment with burner.
  Remedy: Check for proper factory dimensions.
• Cause: Pilot flame too small.
  Remedy: Check for dirty pilot. Check for proper gas pressures.
• Cause: Unit not level.
  Remedy: Re-level unit.
• Cause: Burner ports clogged.
  Remedy: Clean burner.
• Cause: Low gas input.
  Remedy: Clean, incorrect or clogged orifice.

E. Pilot Outage

• Cause: Blockage or restriction of pilot orifice.
  Remedy: See Pilot Flame Observation.
• Cause: Draft/Air currents.
  Remedy: Locate and correct source of draft/air currents.
• Cause: Oxygen depletion.
  Remedy: Provide fresh air make up to heater area.

F. Flash Back Burning/Main Orifice

• Cause: Improper combustion air.
  Remedy: See adjustment instructions.
• Cause: Defective burner.
  Remedy: Replace burner.
• Cause: Unit not level.
  Remedy: Level unit.