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signaling a call for heat. 1st stage sequence of
operation remains the same as above. 2nd stage heat
has a 10 minute delay from the time of 1st stage
ignition.
T T h h e e r r m m o o s s t t a a t t s s a a t t i i s s f f i i e e d d :
(R) and (W) contacts open signaling the control module
to close the gas valve and de-energize the induced draft
blower after approximately 5 seconds post-purge. The
indoor blower motor will continue to operate at the
current speed for 60 or 90 seconds (field selectable)
after the flames are extinguished.
C C o o o o l l i i n n g g C C y y c c l l e e
With the room thermostat system switch in the
"COOLING" position and the fan switch in the "AUTO"
position, the compressor contactor (CC) and the indoor
fan motor (IDM) are energized.
The energized compressor contactor (CC) completes
the circuit to the compressor (CPR) and a secondary
circuit to the outdoor fan motor (ODM). If the
compressor safety controls are closed, the compressor
(CPR) will operate with the outdoor fan motor (ODM).
The indoor fan motor (IDM) will operate. The
thermostat will continue to cycle the compressor and
fans to maintain the desired temperature.
With the thermostat fan switch in the "ON" position, the
indoor fan motor (IDM) will continue to run at constant
circulation of 40 – 50% airflow of selected tap
regardless of compressor and condenser fan operation.
S S a a f f e e t t y y S S e e q q u u e e n n c c e e s s
This product is equipped with safety devices to protect
against abnormal conditions.
The temperature limit switch (TCO) is located on the
blower barrier, and can be accessed through the
blower compartment. This automatic reset device
protects against excessive leaving air temperature. If
this device opens, the gas valve is immediately closed
and will not permit operation until the limit switch
closes.
The rollout switch (RO) is located in the gas
compartment near the inlet of the burners. This is a
manual reset device designed to protect against any
form of flame rollout. If this device is opened the gas
valve is immediately de-energized and the control
(IGN) will lockout the system. The rollout switch (RO)
must be reset before operation is allowed to continue.
The pressure switch (PS) is located in the upper right
side of the gas compartment. This automatic device
assures adequate combustion air pressure. If pressure
against the induced draft blower outlet becomes
excessive, the pressure switch will react and shut off
18-EB27D1-13C-EN
the gas valve, until acceptable combustion pressure is
again available.
If the control (IGN) does not sense flame within the first
trial for ignition period, the gas valve will be de-
energized. The control (IGN) will initiate a 60 seconds
interpurge. Following the interpurge, the control will
perform a second ignition attempt. If the second try is
not successful, the control will start another 60 second
interpurge. After the interpurge, a third attempt will be
tried. If the third try is not successful, the control will
lock out.
If loss of flame occurs during a heating cycle, the
control (IGN) will close the gas valve and cycle through
the ignition trial as stated above.
If control lock out occurs, the control (IGN) will retry a
complete ignition sequence in 1 hour.
The control (IGN) can be reset by removing power to
the unit or by turning the thermostat from "on" to "off"
for approximately three seconds, then back "on".
Final Installation Checklist
☐ Does the unit run and operate as described in the
section on "Sequence of Operation" in response to
the room thermostat?
☐ Are the condenser fan and indoor blower operating
correctly with proper rotation and without undue
noise?
☐ Is the compressor operating correctly and has the
system been checked with a charging chart?
☐ Has the voltage and running current been checked
to deter mine if it is within limits?
☐ Has the thermostat been checked for calibration
and the air discharge grilles adjusted to balance the
system?
☐ Has the ductwork been checked for air leaks and
condensation?
☐ Has the furnace manifold pressure been checked
and adjusted if necessary?
☐ Has the heating air temperature rise been checked?
☐ Has the unit been checked for tubing and sheet
metal rattles? Are there any other unusual noises to
be checked?
☐ Are all covers and panels in place and properly
fastened?
☐ Has the owner been instructed on the proper
operation and maintenance of the unit? Be sure to
leave this manual with the owner.
U U n n i i t t S S t t a a r r t t u u p p
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