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HOMEOWNER’S REFERENCE TABLE
Model No.
Serial No.
Date Installed
Contractor
Contact
Address
Postal Code/Zip Code
Telephone No.
After Hours No.
If different from Installation Contractor:
Service Tech.
Telephone No.
After Hours No.
Fuel Supplier:
Gas Supplier
Contact
Telephone No.
After Hours No.
5 - HOMEOWNER’S REFERENCE
4. When there is a demand for 2
nd
stage heat
from Thermostat W2 or automatic staging , the
control changes the inducer from low to high
speed. When high pressure switch closes,
the control changes indoor blower speed from
Low heat to High heat and energizes high gas
output. If the High pressure switch is open the
Green LED will fl ash. If the High pressure switch
is closed the Green LED will be on. High gas
valve drops out while high pressure switch is
open because it is directly in series with the high
pressure switch.
5. When the thermostat W2 call ends and W1
remains (two stage thermostat), the control
de-energizes the high gas output and immedi-
ately changes inducer speed from high to low.
With the thermostat heating contacts open
(single stage thermostat), the fl ames extinguish
immediately and the induced blower stops after
a 5 second post purge time.
6. Blower off delay is handled by the ECM
(Electronically Commutated Motor). The control
de-energizes the ECM heat signal when the gas
valve de-energizes, and starts a programmed
soft stop (slowly ramp down) delay period.
VARIATIONS
If your system includes air conditioning, your ther-
mostat (supplied by the installer) will likely have
two switches. The fi rst switch is the system switch.
The switch settings usually include HEAT, COOL,
and OFF. Some thermostats have system switches
which include HEAT, COOL, AUTO, and OFF. The
system switch must be in the HEAT or AUTO posi-
tion for the furnace to run.
The second switch is the fan switch. It usually has
settings of ON and AUTO. The fan switch may
be in either position when using the furnace. If the
fan switch is set to ON, the main blower will run
continuously.
