Pressure Switch - Lennox iHarmony 10C16 Installation And Setup Manual

Refer to the iHarmony Zoning System Product Specification for ordering
®
dampers and other various components.
Once the damper control module has been installed and the system
energized, the damper control module will automatically populate the
thermostat commissioning screens. All zone CFM settings will be selected
from commissioning screens for continuous blower and both heating / cooling
blower operations. Testing CFMs for each or all zones may also be performed.
1. The extended damper transformer will only supply power to extended
dampers and relay contacts.
2. The system transformer powers the relay coils (0.4VA each).
3. Combined load of damper transformer (see "Table 1. Zone Damper
Transformer Selection Chart" on page 3) and add 0.4VA per zone relay
to determine the minimum damper transformer VA requirements. Total VA
requirements should not exceed 60VA.
NOTE: Connections illustrated here are for the Lennox recommended spring-
open/power -close dampers. The connections would be different for
other dampers.
NOTE: For extended dampers, use Lennox Part catalog number 56L68 for
zone relays 1 through 4. (Pulse Control Relay, SPDT, 1 N.O. and 1
N.C., 24VAC)

Pressure Switch

(Required for heat pump applications.)
IMPORTANT
Heat Pump Systems Only: Do not use jumper for pressure switch terminals
at the damper control module. System will not function properly without
pressure switch installed.
NOTE: Outdoor unit (heat pump) will not operate if pressure switch is not
installed). The location of the pressure switch may be installed at the
indoor coil using the expansion valve equalizer line connection as an
alternate pressure switch installation location. When the pressure switch
is installed at the indoor coil expansion valve equalizer connection,
a with flare tee will be required and the TXV equalizer line must be
connected to the connection on the tee without a Schrader valve core.
VALVE DEPRESSOR
TEE (LENNOX 87071)
NEW SERVICE
PORT
Figure 5. Tee and Vapor Line High Pressure Switch
A field-provided HFC-410A high pressure switch (catalog number 27W13) is
required for applications with a Lennox heat pump. This switch protects the
system in the event a high pressure condition occurs in the outdoor unit during
heating mode.
The switch operates in tandem with the factory installed high pressure switch,
but connects to the iHarmony control instead. The switch is an auto-reset type
that opens at 550 psig and closes at 425 psig.
NOTE: If a pressure switch is factory installed in the outdoor unit, do not
remove the switch or switch wires.
The damper control module pressure switch may also be fastened directly
to the vapor valve service port using a field-provided tee adapter. This line
becomes the discharge line in heat pump heating mode. Recommend using
pressure switch valve tee adapter (catalog number 87071).
Other conditions:
• Pressure switch status is used only for the heat pump heating and does not
have any affect on non-zone demands.
• Heat pump will stop after the pressure switch status remains open for 60
seconds.
High Pressure Switch must be installed on open side of tee first to prevent
refrigerant loss.
Pressure switch 27W13 should be installed at indoor coil.
7
Install at Outdoor
Coil
HIGH PRESSURE
SWITCH (27W13)
CAUTION