Table of Contents
Advertisement
•
Wire size and overcurrent protection must comply with the National Electrical Code (NFPA-70-latest edition) and
all local codes.
•
Install the furnace so that the electrical components are protected from water.
Supply voltage connections
1.
Provide a power supply separate from all other
circuits. Install overcurrent protection and a
disconnect switch in accordance with local and
national electrical codes. Locate the switch close to
the unit for convenience in servicing.
2.
With the disconnect or fused switch in the OFF
position, check all wiring against the unit wiring
label. See the wiring diagram in this manual.
3.
Remove the wiring box cover screws.
4.
Route all power wiring through a conduit
connector or other proper bushing that is field-
installed into the unit opening and the junction
box. In the junction box, there is a black wire, a
white wire, and a green ground screw.
a. Connect the power supply as shown on the
unit's wiring label located on the inside of
the blower compartment door or the wiring
schematic in this section.
b. Connect the black wire to L1 (hot) from the
power supply.
c. Connect the white wire to neutral.
d. Connect the installer-supplied ground wire to
the green equipment ground screw.
An alternate wiring method is to use a field-
provided 2 in. x 4 in. (5.1 cm x 10.2 cm) box and
cover on the outside of the furnace. Route the
furnace leads into the box using a protective
bushing where the wires pass through the furnace
panel. After making the wiring connections replace
the wiring box cover and screws. See Figure 16.
Figure 16: Electrical wiring
5.
The furnace's control system requires correct
polarity of the power supply and an adequate
ground connection. See Figure 16.
Important: It is possible to relocate the
power connection leads and wiring box to
the opposite side of the furnace. Remove the
screws and cut wire tie holding excess wiring.
Reposition on the opposite side of the furnace
and fasten using the holes provided.
20
Installation Manual: Z8ES Single-Stage Standard ECM Residential Gas Furnaces (Non-condensing Multi-position Standard
and Low NOx)
Low voltage control wiring connections
Install the field-supplied thermostat by following the
instructions that come with the thermostat. With the
thermostat set in the OFF position and the main electrical
source disconnected, connect the thermostat wiring
from the wiring connections on the thermostat to the
terminal block on the control board, as shown in Figure
17 to Figure 20. Electronic thermostats require the
common wire to be connected. Do not use power-stealing
thermostats. Apply strain relief to thermostat wires
passing through cabinet. If air conditioning equipment
is installed, use thermostat wiring to connect the Y and
C terminals on the furnace control board to the correct
wires on the condensing unit (unit outside).
Important: Set the heat anticipator in the room
thermostat to 0.4 A. Setting it lower causes
short cycles. Setting it higher causes the room
temperature to exceed the set points.
Important: Some electronic thermostats do
not have adjustable heat anticipators. Set these
to six cycles per hour. Follow the thermostat
manufacturer's instructions.
The 24 V, 40 VA transformer is sized for the furnace
components only, and must not be connected to power
auxiliary devices such as humidifiers and air cleaners. The
transformer may provide power for an air conditioning or
heat pump contactor.
For Figure 17 and Figure 18:
- Do not bond any of the outdoor unit W wires
together.
- W2 input is only available on two-stage gas heat
models.
- Fossil fuel operation must be controlled by the room
thermostat.
For Figure 20:
If the outdoor section DEMAND RESPONSE feature
is used, connect the room thermostat Y2 connection
directly to the outdoor unit and the outdoor unit Y2
OUT connection to the furnace Y/Y2 input.
Johnson Controls Ducted Systems
NOTICE
NOTICE
Advertisement
Table of Contents
