Practical Pointers | Fives North American

PILOT SYSTEMS

TROUBLE SHOOTING PILOTS - FLAME DETECTION

Symptom: Pilot flame does not energize flame monitoring device A. For all types of flame monitoring devices: Cures:1. Adjust the pilot for a sharp, forceful, blue-white flame that has a "gentle roar." Beware of lazy, floating, drifting, yellow, violet-tipped, or quiet pilot flames, signs of incorrect pilot air/ gas ratio. 2. The proper pilot flame lengths with 6"w.c. mixture pressure are: 4021 (all models)..... 6" 4025-0.... 13" 4027 (all models)..... 6" 4025-1..... 13" 4025-2..... 14" 3. On burners with high main air spin, if the spin is pushing the pilot flame away from the flame monitoring device, interchange positions of the device and the pilot. B. For rectification type flame rod: Check: 1. Pilot too rich causing too much flame on rod, or causing flame to leave pilot tip and lose electrical ground. Best signal will be obtained if the ground area in contact with flame is four times the rod area in contact with flame. 2. Wrong length flame rod. 3. Pilot too small. Does not contact flame rod. More air pressure probably needed. 4. Too much combustion air pressure blowing flame away from rod. C. For ultraviolet cell and lead sulphide cell: Check: 1. Pilot flame too small to reach field of vision. Probably needs more pilot air pressure. 2. Too much combustion air pressure blowing flame out of field of vision. D. For lead sulphide cell: Cures:1. Pilot flame too blue and steady. To be sensed, the flame must have some flicker. A richer pilot flame or raw gas added near pilot may correct this condition.

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