Instructions / Assembly
27
HUM-IN and HUM-OUT. Similar to the HUM terminal, when
utilizing legacy connections, this relay will be closed during
normal heating operation. HUM IN must be powered with
the desired voltage (24 vac from the R terminal or 115 vac
from L1 terminal). The internal relay will close during a call
for heat. Also, the control can provide additional humidifi-
cation features when wired to a communicating thermostat
(1, 2, R, C connections). If the communicating thermostat
is not capable of providing a humidification call, this dedi-
cated relay will function exactly as mentioned above with a
legacy setup. If the communicating thermostat is capable
of providing a humidification call the user is now provided
with 3 modes of operations which can be selected within the
thermostat user menu.
1. ON: Humidifier is turned on with a heat demand.
2. OFF: Humidifier remains off (relay never closes).
3. IND: Humidifier will cycle with humidification demand,
independent of heat demand. This mode allows the user to
select one of 4 fan speeds (25, 50, 75, and 100%).
AUXILIARY ALARM SWITCH:
The control is equipped with a 24VAC Auxiliary Alarm Input
(12 inch purple / white wire attached to pin 6 of 15 pin
connector) which can be utilized with communicating mode
setups (typically used for condensate switch wiring but could
be used with compatible C0
2
sensors or Fire Alarms).
NEUTRAL
HUM-OUT
HUM-IN
NEUTRAL
HUM-OUT
HUM-IN
Figure 36A
24 VOLT
COMMON
HUM-OUT
HUM-IN
Figure 36B
CAUTION
T
O
PREVENT
UNRELIABLE
OPERATION
OR
EQUIPMENT
DAMAGE
,
THE
INLET
GAS
SUPPLY
PRESSURE
MUST
BE
AS
SPECIFIED
ON
THE
UNIT
RATING
PLATE
WITH
ALL
OTHER
HOUSEHOLD
GAS
FIRED
APPLIANCES
OPERATING
.
Natural Gas Minimum: 4.5" w.c. Maximum: 10.0" w.c.
Propane Gas Minimum: 11.0" w.c. Maximum: 13.0" w.c.
INLET GAS SUPPLY PRESSURE
Legacy mode use
In a legacy system (Non-communicating), this auxiliary alarm
input is not operational. Any auxiliary alarm switch must be
used to interrupt Y1 signal either to IFC or to UC.
Communication mode use
This feature can be activated or deactivated through the
thermostat user menus. By default, an AUX switch is nor-
mally closed and opens when the water level in the evapora-
tor coil base pan reaches a particular level. The control will
respond by turning off the outdoor compressor and display
the proper fault codes. If the AUX switch is detected closed
for 30 seconds, normal operation resumes and error mes-
sages are no longer displayed. Installer must wire control
voltage (24VAC) to AUX switch to ensure the Auxiliary Alarm
Input has 24VAC during normal operation.
G
AS
S
UPPLY
AND
P
IPING
The furnace rating plate includes the approved furnace gas input
rating and gas types. The furnace must be equipped to operate
on the type of gas applied. This includes any conversion kits
required for alternate fuels and/or high altitude.
Inlet gas supply pressures must be maintained within the ranges
specified in the following table. The supply pressure must be
constant and available with all other household gas fired appli-
ances operating. The minimum gas supply pressure must be
maintained to prevent unreliable ignition. The maximum must
not be exceeded to prevent unit overfiring.
HIGH ALTITUDE DERATE
When this furnace is installed at high altitude, the appropriate
High Altitude orifice kit must be applied. This is required due to
the natural reduction in the density of both the gas fuel and
combustion air as altitude increases. The kit will provide the
proper design certified input rate within the specified altitude
range.
High altitude kits are purchased according to the installation
altitude and usage of either natural or propane gas. Consult the
furnace Specification Sheet for appropriate kits.
Do not derate the furnace by adjusting the manifold pressure to
a lower pressure than specified on the furnace rating plate. The
combination of the lower air density and a lower manifold pres-
sure will prohibit the burner orifice from drawing the proper