Page 32
506176−01 01/2010
Other Unit Adjustments
Primary and Secondary Limits
The primary limit is located on the heating compartment
vestibule panel. The secondary limits (if equipped) are lo-
cated in the blower compartment, attached to the back side
of the blower. These limits are factory set and require no
adjustment.
Flame Rollout Switches (Two)
These manually reset switches are located on (or inside of)
the burner box. If tripped, check for adequate combustion
air before resetting.
Pressure Switches
The pressure switch assembly (includes two switches) is
located in the heating compartment adjacent to the com-
bustion air inducer. These switches check for proper com-
bustion air inducer operation before allowing ignition trial.
The switches are factory−set and require no adjustment.
Temperature Rise
Unit must be adjusted for the temperature rise range and
within the allowable external static pressure as listed on
unit nameplate.
Place the unit into operation with a second−stage heating
demand. After supply and return air temperatures have
stabilized, check the temperature rise. If necessary, adjust
the heating blower speed to maintain the temperature rise
within the range shown on the unit nameplate. Increase the
blower speed to decrease the temperature rise. Decrease
the blower speed to increase the temperature rise. Failure
to properly adjust the temperature rise may cause erratic
limit operation.
Blower Speeds
NOTE − CFM ratings are taken external to unit with a dry
evaporator coil and without accessories. See blower per-
formance data which begins on page 33.
Thermostat Heat Anticipation
Set the heat anticipator setting (if adjustable) according to
the amp draw listed on the wiring diagram that is attached
to the unit.
Electrical
1 − Check all wiring for loose connections.
2 − Check for the correct voltage at the furnace (furnace
operating).
3 − Check amp-draw on the blower motor.
Motor Nameplate__________Actual__________
NOTE − Do not secure the electrical conduit directly to the
air ducts or structure.
Electronic Ignition
The two−stage SureLight
®
integrated control used in
G60UH units has an added feature of an internal Watch-
guard control. The feature serves as an automatic reset de-
vice for ignition control lockout caused by ignition failure.
This type of lockout is usually due to low gas line pressure.
After one hour of continuous thermostat demand for heat,
the Watchguard will break and remake thermostat demand
to the furnace and automatically reset the control to begin
the ignition sequence.
Flue And Chimney
1 − Check flue pipe, chimney and all connections for tight-
ness and to make sure there is no blockage.
2 − Check unit for proper draft.
3 − Is pressure switch closed? Obstructed flue will cause
unit to shut off at pressure switch. Check flue and outlet
for blockages.
4 − Reset manual flame rollout switches on burner box.
Failure To Operate
If the unit fails to operate, check the following:
1 − Is the thermostat calling for heat?
2 − Are access panels securely in place?
3 − Is the main disconnect switch closed?
4 − Is there a blown fuse or tripped circuit breaker?
5 − Is the filter dirty or plugged? Dirty or plugged filters will
cause the limit control to shut the unit off.
6 − Is gas turned on at the meter?
7 − Is the manual main shut-off valve open?
8 − Is the internal manual shut-off valve open?
9 − Is the unit ignition system in lock out? If the unit locks out
again, inspect the unit for blockages.
To Next Page
Loading...
Need help?
General
