506326-01
Page 15 of 20
Issue 0941
Limit Control
A fixed temperature limit control is provided which will shut
off the gas to the burners if the unit is overheated for any
reason. The control must not be adjusted or relocated.
Rollout Switch
If for any reason the exchanger were to become blocked,
there is a temperature sensitive switch located above the
burners that will turn off the burners. After correcting the
problem, this switch must be manually reset by pressing the
button on top of it.
High Altitude
In both the United States and Canada, this unit is approved
for operation at altitudes from 0 to 4500 feet above sea level
without any required modifications. From 4500 to 7500 feet,
the gas manifold pressure needs to be adjusted according
to the information shown in Table 5. To adjust the manifold
pressure, refer to previous section
Checking and Adjusting
Gas Input
on page 13. For installations above 7500 feet,
refer to the National Fuel Gas Code.
Installation and Operation in Extremely Cold Weather
Areas
In areas where extremely cold outdoor temperatures (below
– 20°F) can be expected, some additional installation and
operating precautions should be taken. The following
precautions are designed to prevent possible vent system
ice blockage that could result in safety shutdown of the
burners:
1.
Adjust to the highest achievable temperature rise within
the rise and static pressure ranges specified on the rating
plate. Depending on specific model, it may be possible
to change to a lower heating blower speed tap to get a
higher temperature rise. This also increases comfort.
2.
Make sure there are no leaks of outside air into the return
air system.
3.
Keep the outside louver grille as free as possible of any
ice that may form and obstruct the flue outlet.
