PREMIX SYSTEMS
TROUBLE SHOOTING AIR/GAS RATIO REGULATORS ATMOSPHERIC SERVICE ON PREMIX SYSTEMS
A. Symptom: At high fire, outlet pressure goes negative or flame goes lean Causes:
1. Insufficient supply pressure or supply line is undersized. 2. Regulator is undersized. 3. Leak around lower diaphragm or adjustment plug. 4. Hole in large diaphragm.
B. Symptom: Fire goes rich at "Low"
Causes: 1. Spring adjustment set "positive." 2. Hole in small diaphragm.
3. Limiting orifice open beyond normal to compensate for any conditions under "A." 4. Regulator vent not cross-connected to combustion chamber which has negative pressure. 5. Valve not seating because of dirt or damage.
C. Symptom: Fire goes lean at "Low"
Causes: 1. Spring adjustment set "negative."
2. Regulator vent not cross-connected to combustion chamber which has positive pressure.
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