SYSTEM OPERATION
13
Optional 24 VAC Humidifier Connection
Locate the factory supplied 4” Brown wire connected to the
low fire pressure switch. Strip insulation from the end of
the wire & connect field installed low voltage control wiring.
Refer to diagram below for low voltage connection of field
supplied 24 VAC humidifier.
Fossil Fuel Applications
This furnace can be used in conjunction with a heat pump
in a fossil fuel application. A fossil fuel application refers to
a combined gas furnace and heat pump installation which
uses an outdoor temperature sensor to determine when to
run the heat pump or gas furnace.
For non-communicating single stage heat pump
installations a fossil fuel kit can be used. Follow the wiring
guidelines in the fossil fuel kit installation instructions.
All furnace connections must be made to the furnace
integrated control module and the “FURNACE” terminal
strip on the fossil fuel control board.
For Fossil Fuel systems the heat pump is given priority
when a compressor balance point lockout condition is not
present. Transitions from primary heat pump heating to
backup gas heating will result in full capacity operation
during the first thermostat call. The furnace PCB algorithms
will then continuously adjust the stage times or the percent
capacity after the initial call in an attempt to satisfy the
thermostat at the target runtime.
Automatic Fossil Fuel Adjustment: If both compressor
balance point and backup heat balance point lockouts are
not present, the furnace algorithms will determine if the
heat pump is capable of satisfying the thermostat in the
selected target runtime. If the heat pump is not capable
of this it will be locked out until the furnace can satisfy
the thermostat, under the target runtime, while running
completely in low stage. At that point, an attempt will be
given to the heat pump and a decision made to keep using
gas heat or to transition back to the heat pump.
115 Volt Line Connection of Electronic Air
Cleaner
WARNING
High Voltage!
To avoid personal injury or death
due to electrical shock, disconnect
electrical power before servicing or
changing any electrical wiring.
The accessory load specifications are as follows:
EAC
1.0 Amp maximum at 120 VA
The furnace integrated control module is equipped with
a line voltage accessory terminal for controlling power
to an optional field supplied electronic air cleaner or any
device required to operate in parallel with a circulating fan
demand.
To connect an electronic air cleaner using the
line voltage EAC terminal:
•
Turn OFF power to the furnace before installing any
accessories.
•
Follow the air cleaner manufacturers’ instructions
•
for locating, mounting, grounding, and controlling
accessories. Utilize 1/4” quick connect terminals to
make accessory wiring connections to the furnace
integrated control module.
•
Connect the hot terminal utilized for accessory
operation to the EAC terminal and the neutral side of
power to NEUTRAL bus on the integrated furnace control
or the neutral connection in the furnace junction box.
•
All field wiring must conform to applicable codes.
•
Connections should be made as shown.
•
If it is necessary for the installer to supply additional
line voltage wiring to the inside of the furnace, the wiring
must conform to all local codes, and have a minimum
temperature rating of 105°C.
•
All line voltage wire splices must be made inside the
furnace junction box.
Auxiliary Alarm Switch
The control is equipped with a 24VAC Aux Alarm to be
used for a condensate switch install (designated by
“Condensate” on the control).
These contacts could also
be used with compatible CO2 sensors or Fire Alarms. By
default, an AUX switch is normally closed and opens when
the water level in the evaporator coil base pan reaches an
undesirable level. The control will respond by turning off
the outdoor condensing unit and display EEd. If the AUX
switch is detected closed for 30 seconds, normal operation
resumes and error messages are no longer displayed.
