PREMIX SYSTEMS
TROUBLE SHOOTING PREMIX BURNERS
A. Symptom: Not enough gas to burners Causes: 1. Mixer too large for burner nozzle or nozzles causing low
suction at gas limiting orifice. Install larger displacement rod, smaller mixer, larger nozzle, or if necessary, cross connect the regulator to the air or mixture line. More gas supply pressure is required if cross-connected. 2. Regulator outlet pressure too low. 3. Mixer venturi dirty or obstructed. 4. Burner nozzle restricted by foreign matter or from being overheated. 5. Burner tile restricted. 6. Restricted mixture piping. 7. High positive pressure in combustion chamber without regulator vent being cross-connected, or with inadequate gas supply pressure. 8. Restricted gas piping between regulator and mixer.
B. Symptom: Burner flashing back (flame in mixture line) Causes: 1. Non-uniform mixture piping causing too low a mixture pressure. 2. Mixture pressure being turned too low. 3. Pulsating gas or air supply. 4. Turbulence in a burner nozzle caused by its being too close to a pipe fitting. 5. Nozzle being heated beyond ignition temperature of mixture.
C. Symptom: Burner unstable
Causes: 1. Mixture too rich or too lean.
2. On some types, no free air in combustion area. 3. On sealed-in tunnel type burners, no flame retention step from nozzle bore to tile. 4. On sealed-in type burners, tile in bad condition. 5. On sealed-in type burners, tile broken loose from, or plugs left out of, mounting plate. 6. On self-piloted burners, piloting holes partially or wholly clogged. 7. On self-piloting nozzles, nozzle too close to elbow tee.
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