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Installer's Guide
Figure 20. Power Connections
Figure 21. Mounted Disconnect Location
Control Wiring (Class II)
Low voltage control wiring should not be run in conduit with power
wiring unless Class 1 wire of proper voltage rating is used. Route
the thermostat cable or equivalent single leads of No. 18 AWG
colored wire from the thermostat subbase terminals through the
rubber grommet on the unit. See Figures 2 or 5 for the control
entry (24V Entry) location. Make connections as shown on the
unit wiring diagram.
Do not short thermostat wires since this will damage the control
transformer.
Refer to Table 6 for recommended wire sizes and lengths for install-
ing the unit thermostat. The total resistance of these low voltage
wires must not exceed one (1) ohm. Any resistance in excess of 1
ohm may cause the control to malfunction because of the exces-
sive voltage drop.
Table 6. Thermostat Wire Size and Maximum Length
W
i
e r
S
z i
e
1
8
1
6
1
4
Page 20
Contactor
Unit Ground Lug
M
a
i x
m
u
m
L
e
n
t g
h
7
5
1
2
5
2
0
0
Thermostat Operation
Operation of the unit heating or cooling cycles is controlled by the
comfort control. Once the system mode is set to either HEAT or
COOL, unit operation is automatic. The fan ON setting provides
continuous indoor blower operation. The AUTO setting provides
indoor blower operation during the compressor heating and cooling
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 recom-
mended that the fan only be used in the AUTO mode.
NOTE: The 4DCY4 units require either a *CONT402,
*CONT802 or *CONT803 Comfort Control. Do not install any
other model of thermostat with this 4DCY4 unit. Otherwise,
mis-operation could result due to the dual fuel nature of this
unit. Note: 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.
NOTE: A field installed jumper wire (18 AWG minimum
conductor) is required between the W1 and W2/X2 low
voltage wires at the 4DCY4 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 4DCY4 unit will transition automatically to
high fire and operate on high fire for the remaining duration of
the call for auxiliary heat.
NOTE: 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 4DCY4 unit. There is no jumper to cut
on the *CONT802 and *CONT803 Comfort Controls
TWO MODES OF OPERATION:
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.
RESTRICTED: 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.
NON-RESTRICTED: This mode of operati on allows the unit to
operate in the heat pump mode during the first call, or stage,
of heat commanded by the indoor thermostat. 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
second 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, page 21, for field wiring
instructions.
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