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1.
When possible, position the sensor some distance away from the coil rather
than in the immediate coil area. The discharge air sensor should be located at
least 10 inches above the coil if possible.
2.
Fasten the sensor bracket to the plenum with two self-tapping sheet metal
screws.
3.
Connect wires to DAS on zone control panel. Not on the air handler control
or IFC (see “Figure 20. Option 2 - Typical Lennox Heat Pump and Lennox
Variable-Speed Air Handler (Troubleshooting)” on page 20 ).
4.
Be sure that the tip of the sensor is located approximately 10 inches from the
indoor coil in the discharge plenum, and half the depth of the plenum, and
center over the discharge airflow, side-to-side.
IMPORTANT
For the DAS, transversing the supply duct for the best location is recommended.
Optimal location is critical to the proper operation of the zoning system
plenum
coil
INDOOR
UNIT FRONT
VIEW
sensor centered in
discharge airflow
(see note 1)
Temperature
19
(254)
INDOOR UNIT
SIDE VIEW
ECB
Electric
Heat
Strips
NOTE - FOR UNITS WITH HUMIDITROL— Discharge air sensor
(DAS) MUST be located on the output side of the EDA (if used; see
Humiditrol Zoning Accessory Installation 506064-02)
SENSOR PROBE
see PROBE
MOUNTING
note below
PLENUM
SENSOR
MOUNTING
DETAIL
Fully insert into plenum
Figure 4. Discharge Air Sensor Installation
1.9.2. Zone Control Panel
IMPORTANT
The electrical power source for the zone control system, i.e. the transformer
primary, and furnace or air handler unit must be the same source. In addition, the
zone control system power-up must occur at the same time or before the furnace
or air handler unit is powered up.
Select an installation site for the Harmony III zoning system control considering the
following location parameters:
• Is conveniently accessible and centrally located to facilitate wiring from
thermostats, dampers, pressure switch (if used), and HVAC equipment.
• Is in a non-condensing area (such as a closet).
• Is NOT in a laundry room (nor other room in the house where the humidity would
typically be much higher than the rest of the house).
•
Is NOT in any part of the building where the temperature may exceed 150°F.
1.9.3. Thermostats
Identify the best location for a thermostat in each zone. If two or more rooms are
within a single zone, place the thermostat in a location that is central to all rooms.
For example, if a zone contains two bedrooms, try to place the thermostat in a
hallway near both bedrooms.
Do not install thermostats in drafty areas, behind doors, in corners, near radiant heat
sources (appliances), near sunny windows, near concealed pipes and chimneys,
nor in unconditioned spaces such as closets or exterior walls.
1.9.4. Transformer
Obtain an appropriately-rated transformer (see “Table 5. 24VAC Transformer
Selection Chart” on page 6). Install the transformer in either the indoor unit or
in an electrical junction box near the zone control panel.
NOTE:
Two transformer systems need to be in phase with each other.
1.9.5. Dampers
NOTE:
The power source for the transformer must be the same power source as
the indoor unit’s transformer.
Motorized dampers in the supply duct system regulate air to the zones. Some
applications will be unique and require more than one damper per zone. If
additional dampers are required, refer to the wiring diagram in “1.12. Component
Specific Wiring” on page 14. Also, if more than six dampers are used, another
transformer and isolation relay will be necessary.
For more effective zone isolation, the return duct system may also be dampered
by zone. Dampers for each zone must be wired in parallel. Install dampers in the
desired locations; then run thermostat wire from the damper to the zone control
panel and damper relays as needed.
1.9.6. Zone Linking
Zone link a small zone to a large zone by wiring dampers in a manner similar to
figure 4. Effectively, this distributes some of the small zone’s air to another zone to
reduce the chance of overheating or overcooling the smaller zone. Refer to “Table
8. Lennox AC or Heat Pump Units” on page 7 which shows an example of an
unequal zone and how to adjust to bring it within 25% of the average CFM. Figure
Summary of Contents for Harmony III
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