Lennox International Inc. TUA125S User Manual
Page 17
ADJUSTMENTS
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.
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.
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.
Limit Control
The limit control switch is factory set and not field
adjustable.
adjustable.
Louver Vane Adjustment
Rotate louver vanes to direct airflow upward,
downward, straight, or any combination of these
directions.
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.
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.
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
(0-610)
2001-3000
(610-914)
3001-4000
(915-1219)
4001-5000
(1220-1524)
5001-6000
(1524-1829)
6001-7000
(1829-2134)
7001-8000
(2134-2438)
8001-9000
(2439-2743)
9001-10000
(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.