18-BG07D1-1A-EN
23
Table 16. Thermostat Wire Size and Max. Length
Wire Size
Maximum Length
18 75
16 125
14 200
TThheerrmmoossttaatt
Operation of the unit heating and cooling cycles is
automatic when the system is set to HHEEAATT or CCOOOOLL
(the optional automatic changeover thermostat, when
set to AAUUTTOO, automatically changes to heat or cool
with an appropriate room temperature change). The
fan can be set to OONN, causing continuous evaporator
(indoor) fan operation at constant circulation -
approximately 40 - 50% of nominal airflow at selected
dipswitch settings or set to AAUUTTOO causing fan
operation to coincide with heating or cooling run
cycles. Continuous fan mode during cooling operation
may not be appropriate in humid climates. If the indoor
air exceeds 60% relative humidity or simply feels
uncomfortably humid, it is recommended that the fan
only be used in the AAUUTTOO mode.
NNootteess::
• The 4DCZ5 units require either a *CONT402,
*CONT802 or *CONT803 Comfort Control.
Do not install any other model of thermostat
with this 4DCZ5 unit. Otherwise, mis-
operation could result due to the dual fuel
nature of this unit.
• A BAYSEN02ATEMPA outdoor temperature
sensor must be purchased separately and
installed in order to use the *CONT802 and
*CONT803 Comfort Controls with this unit.
A BAYSEN01ATEMPA outdoor sensor is
shipped with the *CONT402.
• A field installed jumper wire (18 AWG
minimum conductor) is required between
the W1 and W2/X2 low voltage wires at the
4DCZ5 unit when using the *CONT802 or
*CONT803 Comfort Controls since these two
controls produce only a W1 output for
auxiliary heat. This will result in low fire gas
heating for 10 minutes or for as long as W1
is present if less than 10 minutes. Then, if
the W1 signal is still present from the
Comfort Control, the 4DCZ5 unit will
transition automatically to high fire and
operate on high fire for the remaining
duration of the call for auxiliary heat.
• The JP1 Dual Fuel jumper wire on the
printed circuit board of the *CONT402 must
be cut for proper and reliable operation of
this dual fuel 4DCZ5 unit. There is no jumper
to cut on the *CONT802 and *CONT803
Comfort Controls.
TTWWOO MMOODDEESS OOFF OOPPEERRAATTIIOONN::
The unit can be installed and configured to operate in
one of two different heating modes: restricted and non-
restricted. A brief explanation of each mode follows.
RREESSTTRRIICCTTEEDD:: In the restricted mode of operation an
outdoor temperature sensor is used to cause the unit to
operate in the heat pump mode above a selected
outdoor temperature and to operate in the gas heating
mode below the selected outdoor temperature. The gas
heat will operate with the heat pump when the unit
requires a defrost cycle. The gas heat is used to offset
the effect of the unit going into the cooling mode
during defrost. For the *CONT402, the unit will be
commanded to transition to gas heat even when the
outdoor temperature is above the selected outdoor
temperature changeover point if the heat pump
capacity is not enough to maintain the indoor
temperature at the desired heating setpoint.
NNOONN--RREESSTTRRIICCTTEEDD:: This mode of operation allows the
unit to operate in the heat pump mode during the first
or second call, or stage, of heat commanded by the
indoor thermostat. During the first stage of heat pump
mode the heat pump will operate on low speed. During
the second stage, the heat pump will operate on high
speed. If the heat pump capacity is sufficient, gas heat
will not be required. If the heat pump capacity is not
enough to maintain the indoor temperature at the
desired heating setpoint, the thermostat will call for the
third stage of heat. At that point, the gas heat will begin
to operate and the heat pump will be locked out. As in
the restricted mode, the gas heat will act as
supplementary heat during the unit’s defrost cycle.
See the Field Wiring Diagram, for field wiring
instructions.
IImmppoorrttaanntt:: Upon completion of wiring, check all
electrical connections, including factory
wiring within the unit. Make sure all
connections are tight. Replace and secure
all electrical box covers and access doors
before leaving the unit or turning on the
power to the unit.
NNoottee:: The outdoor sensor should be located in an area
which will provide a representative outdoor
ambient temperature reading.
UUnniitt IInnssttaallllaattiioonn
To Next Page
Loading...
