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START- -UP, ADJUSTMENT, AND SAFETY
CHECK
NOTICE
Important Installation and Start- -up Procedures
Failure to follow this procedure may result in a nuisance
smoke or odor complaint.
The manifold pressure, gas rate by meter clocking,
temperature rise and operation must be checked after
installation.
Minor smoke and odor may be present
temporarily after start- -up from the manufacturing process.
Some occupants are more sensitive to this minor smoke and
odor. It is recommended that doors and windows be open
during the first heat cycle.
General
1. Furnace must have a 115-v power supply properly connec-
ted and grounded.
NOTE: Proper polarity must be maintained for 115-v wiring.
Control status indicator light flashes rapidly and furnace does not
operate if polarity is incorrect of if the furnace is not grounded.
2. Thermostat wire connections at terminals R, W/W1, G, and
Y/Y2 must be made at 24-v terminal block on furnace con-
trol.
3. Natural gas service pressure must not exceed 0.5 psig (14-
in. w.c., 350 Pa), but must be no less than 0.16 psig (4.5-in.
w.c., 1125 Pa).
4. Blower door must be in place to complete 115-v electrical
circuit and supply power to the furnace components.
CAUTION
!
UNIT OPERATION HAZARD
Failure to follow this caution may result in intermittent unit
operation or performance dissatisfaction.
These furnaces are equipped with a manual reset limit
switch in burner assembly. This switch opens and shuts off
power to the gas valve if an overheat condition (flame
rollout) occurs in the burner assembly/enclosure. Correct
inadequate combustion- -air supply, improper gas pressure
setting, improper burner or gas orifice positioning, or
improper venting condition before resetting switch. DO
NOT jumper this switch.
Before operating furnace, check flame rollout manual reset switch
for continuity. If necessary, press button to reset switch.
EAC-1 terminal is energized whenever blower operates. HUM
terminal is only energized when the gas valve is energized in
heating.
Thermostat Setup Switch
This furnace can be installed with either a single- -stage heating or a
2- -stage heating thermostat. Setup switch SW- -1 (LHT) is used to
configure the furnace for single or two stage thermostat operation.
For single- -stage thermostats, connect thermostat W to W/W1 at
furnace control terminal block. See Fig. 34. For single- -stage
thermostats, the control will determine, based on length of previous
heating on and off cycles, when to operate in low- - and high- -gas
heat for optimum comfort. Setup switch SW- -1 (LHT) must be in
the factory- -shipped OFF position. See Fig. 34 and 66 for setup
switch information.
If a 2- -stage heating thermostat is to be used, move SW- -1 (LHT) to
ON position before starting furnace. This overrides built- -in control
process for selecting high and low fire and allows the 2- -stage
thermostat to select gas heating modes. The W2 from thermostat
must be connected to W2 on control terminal block.
Prime Condensate Trap with Water
WARNING
!
CARBON MONOXIDE POISONING HAZARD
Failure to follow these warnings could result in personal injury
or death.
Failure to use a properly configured trap or NOT
water- -priming trap before operating furnace may allow
positive pressure vent gases to enter the structure through drain
tube. Vent gases contain carbon monoxide which is tasteless
and odorless.
CAUTION
!
UNIT OPERATION HAZARD
Failure to follow this caution may result in intermittent unit
operation or performance satisfaction.
Condensate trap must be PRIMED or proper draining may
not occur. The condensate trap has two internal chambers
which can ONLY be primed by pouring water into the
inducer drain side of condensate trap.
1. Remove upper and middle collector box drain plugs oppos-
ite of the condensate trap. See Fig. 61.
2. Connect field-supplied 5/8-in. (16 mm) ID tube with at-
tached funnel to upper collector box drain connection. See
Fig. 61.
3. Pour one quart (liter) of water into funnel/tube. Water
should run through collector box, overfill condensate trap,
and flow into open field drain.
4. Remove funnel; replace collector box drain plug.
5. Connect field-supplied 5/8-in. (16 mm) ID tube to middle
collector box drain port.
6. Pour one quart (liter) of water into funnel/tube. Water
should run through collector box, overfill condensate trap,
and flow into open field drain.
7. Remove funnel and tube from collector box and replace col-
lector box drain plug.
Purge Gas Lines
If not previously done, purge the lines after all connections have
been made and check for leaks.
WARNING
!
FIRE OR EXPLOSION HAZARD
Failure to follow this warning could result in personal
injury, death, and/or property damage.
Never purge a gas line into a combustion chamber. Never
test for gas leaks with an open flame. Use a commercially
available soap solution made specifically for the detection
of leaks to check all connections. A fire or explosion may
result causing property damage, personal injury or loss of
life.
62
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