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II-PLACEMENT AND INSTALLATION
Make sure unit is installed in accordance with installation
instructions and applicable codes.
III-START‐UP
A-Preliminary and Seasonal Checks
1 - Inspect electrical wiring, both field and factory installed
for loose connections. Tighten as required.
2 - Check voltage at disconnect switch. Voltage must be
within range listed on the nameplate. If not, consult the
power company and have voltage condition corrected
before starting unit.
B-Heating Start‐Up
WARNING
Shock and burn hazard.
SL280UHNV units are equipped with a hot surface
ignition system. Do not attempt to light manually.
1 -
STOP
! Read the safety information at the beginning of
this section.
2 - Set the thermostat to the lowest setting.
3 - Turn off all electrical power to the unit.
4 - This furnace is equipped with an ignition device which
automatically lights the burners. Do
not
try to light the
burners by hand.
5 - Remove the access panel.
6 - Turn switch on gas valve to
OFF
. Do not force. See
figure 17.
7 - Wait five minutes to clear out any gas. If you then smell
gas, STOP! Immediately call your gas supplier from a
neighbor's phone. Follow the gas supplier's instruc
tions. If you do not smell gas go to next step.
FIGURE 17
NEGATIVE AIR
PRESSURE PORT
POSITIVE AIR
PRESSURE PORT
MANIFOLD
PRESSURE TAP
INLET
GAS VALVE SHOWN IN THE ON POSITION
OUTLET
SUPPLY
PRESSURE
TAP
GAS VALVE
8 - Move switch on gas valve to
ON
. Do not force. See fig
ure 17.
9 - Replace the access panel.
10- Turn on all electrical power to to the unit.
11- Set the thermostat to desired setting.
NOTE - When unit is initially started, steps 1 through 11
may need to be repeated to purge air from gas line.
Turning Off Gas To Unit
1 - Set thermostat to lowest setting.
2 - Turn off all electrical power to unit if service is to be per
formed.
3 - Remove access panel.
4 - Move switch on valve to
OFF
. Do not force.
5 - Replace access panel.
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, call the service technician to inspect the unit for
blockages.
10 -Is pressure switch closed? Obstructed flue will cause
unit to shut off at pressure switch. Check flue and outlet
for blockages.
11 -Are flame rollout switches tripped? If flame rollout
switches are tripped, call the service technician for in
spection.
C-Safety or Emergency Shutdown
Turn off unit power. Close manual and main gas valves.
D-Extended Period Shutdown
Turn off thermostat or set to “UNOCCUPIED” mode. Close
all gas valves (both internal and external to unit) to guaran
tee no gas leak into combustion chamber. Turn off power to
unit. All access panels and covers must be in place and se
cured.
IV-HEATING SYSTEM SERVICE CHECKS
A-CSA Certification
All units are CSA design certified without modifications.
Refer to the SL280UHNV Installation Instruction.
B-Gas Piping
CAUTION
If a flexible gas connector is required or allowed by
the authority that has jurisdiction, black iron pipe
shall be installed at the gas valve and extend outside
the furnace cabinet.
WARNING
Do not over torque (800 in-lbs) or under torque (350
in-lbs) when attaching the gas piping to the gas
valve.
