LX LT Low Nox

1. Lean fuel/air mixture—Low supply pressure.Correct supply pressure to assure 3.0" W.C. (Nat.)or 9.0" WC (LP) manifold pressure when firing. 2. Lean fuel/air mixture—Too much negative combustion chamber pressure (draft). Increase draft openings by sliding damper beneath burners (see Section 10.3). 3. Lean fuel/air mixture—Low gas heat content. Increase draft openings by sliding damper beneath burners (see Section 10.3).

1. Wrong gas. Make sure gas supply matches gas indicated on rating plate 2. Burner damage. Replace burner

1. Low water temperature. Flue product moisture will condense at the start-up until the heater water temperature reaches the normal operating conditions. 2. Heater plumbed backwards. Correct Plumbing

1. Water flow through heater too low. Check temperature rise according to Section 7.6 of this manual. If temperature rise is too high, check pipe size, pump capacity. Look for obstruction or closed valve in system.

1. Gas valve not at “on” position. Turn knob to “on” position. 2. Air in gas line. Cycle ignition sequence until air is out of the gas line 3. Gas valve failed. Replace gas valve 4. No power to gas valve. Check controls for proper operation 5. Low gas pressure. Check supply pressure and manifold pressure

1. Inadequate gas supply. Gas meter too small. Gas line from meter to heater too small 2. Low manifold gas pressure. Gas pressure on heater manifold, should be adjusted to 3.0" W.C. for natural gas, 9.0" WC for LP gas 3. Heater size inadequate. Replace with heater of higher input. 4. Temperature rise set incorrectly. Adjust temperature rise according to Section 7.6 of this manual

1. No power. Check circuit breakers and power source 2. Pump defective. Replace 3. Incorrectly wired. Recheck wiring 4. Time clock settings not synchronized with actual time. Check time clock setting.

1. Rich fuel/air mixture—Hi manifold pressure. Correct manifold pressure to 3.0" WC (Natural)or 9.0" WC (LP) 2. Rich fuel/air mixture—Too little negative combustion chamber pressure (draft). a) Locate and correct combustion system sealing deficiencies (see Section 10.3). b) Decrease draft openings by sliding damper beneath burners (see Section 10.3). 3. Rich fuel/air mixture—High gas heat content. Decrease draft openings by sliding damper beneath burners (see Section 10.3).