Lennox International Inc TUA125S, TUA45S Adjustments, Limit Control, Louver Vane Adjustment

High Altitude

Units may be fired at full input up to 2000 ft. (610m) above sea level. Above 2000 ft. (610m), manifold pressure must be reduced by 4 percent for each 1000 feet above sea level or as specified by local authority having jurisdiction. Adjust pressure regulator to pressure shown in table 6 for natural gas and table 7 for LP/propane gas. The combustion air blower proving switch is factory set. No adjustment is necessary.

Gas Pressure

Check gas line pressure with unit firing at maximum rate. A minimum of 5.0" w.c. for natural gas or 10.4" w.c. for LP/propane gas should be maintained for proper unit operation. After line pressure has been checked and adjusted, check manifold pressure. Correct manifold pressure is shown on the unit rating plate. See figures 11, 12 and 13 for gas pressure adjustment screw location. A natural gas to LP/propane gas changeover kit is required to convert unit. Refer to installation instructions provided with changeover kit for conversion procedure.

ADJUSTMENTS

Limit Control

The limit control switch is factory set and not field adjustable.

Louver Vane Adjustment

Rotate louver vanes to direct airflow upward, downward, straight, or any combination of these directions.

Combustion Air Inducer Proving Switch

This combustion air inducer proving switch checks for proper combustion air inducer operation before allowing an ignition trial. The switch is factory set and no field adjustment is necessary.

Flame Rollout Switch

The flame rollout switch(es) on 45, 60 or 75 units are located on the burner box top, behind the ignition control board. The flame rollout switch on 100 or 125 units is located on the manifold bracket above the top burner. This normally closed switch opens on a temperature rise. Check for adequate combustion air and proper venting before manually resetting switch.

TABLE 6

NATURAL GAS MANIFOLD PRESSURES - in.wg. (kPa)

ALTITUDE FT. (M)

MODEL	0-2000	2001-3000	3001-4000	4001-5000	5001-6000	6001-7000	7001-8000	8001-9000	9001-10000
	(0-610)	(610-914)	(915-1219)	(1220-1524)	(1524-1829)	(1829-2134)	(2134-2438)	(2439-2743)	(2744-3048)
TUA045SN	3.5 (0.87)*	2.7 (0.67)	2.5 (0.62)	2.2 (0.55)	2.0 (0.50)	1.8 (0.45)	1.6 (0.40)	1.4 (0.35)	1.3 (0.32)
TUA060SN	3.5 (0.87)*	2.7 (0.67)	2.5 (0.62)	2.2 (0.55)	2.0 (0.50)	1.8 (0.45)	1.6 (0.40)	1.4 (0.35)	1.3 (0.32)
TUA075SN	3.5 (0.87)*	2.7 (0.67)	2.5 (0.62)	2.2 (0.55)	2.0 (0.50)	1.8 (0.45)	1.6 (0.40)	1.4 (0.35)	1.3 (0.32)
TUA100SN	3.5 (0.87)*	2.7 (0.67)	2.5 (0.62)	2.2 (0.55)	2.0 (0.50)	1.8 (0.45)	1.6 (0.40)	1.4 (0.35)	1.3 (0.32)
TUA125SN	3.5 (0.87)*	2.7 (0.67)	2.5 (0.62)	2.2 (0.55)	2.0 (0.50)	1.8 (0.45)	1.6 (0.40)	1.4 (0.35)	1.3 (0.32)

*No adjustment required.

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