Lennox Harmony III User Manual

14
120
VAC
24
VAC
EXTENDED
DAMPER
TRANSFORMER
(SEE NOTE)
(NOT TO EXCEED
75 VA) CLASS II
WIRING
120 VAC
24 VAC
ZONE
RELAY K4
ZONE
RELAY K3
ZONE
RELAY K2
ZONE
RELAY K1
ZONE 1
DAMPER
ZONE 2
DAMPER
ZONE 3
DAMPER
ZONE 4
DAMPER
EXTENDED
ZONE 1
DAMPER
EXTENDED
ZONE 2
DAMPER
EXTENDED
ZONE 3
DAMPER
EXTENDED
ZONE 4
DAMPER
EXTENDED
DAMPER
WIRING
ZONE CONTROL,
THERMOSTATS,
and DAMPERS
TRANSFORMER
Figure 13. Heating Air Reduction Jumpers
NOTE: The extended damper transformer rating should be sized to adequately
handle zone dampers (1-4) plus relays (K1-K4) not to exceed class II
wiring limit of 75 VA. Combined load of zone dampers and zone relays not
to exceed 60 VA. Use Lennox Catalog number 56L68 for Zone Relays 1
through 4.
1.11.2. Discharge Air Sensor (DAS) Probe
Wire discharge air sensor probe to zone control panel. The variable immersion-
temperature probe is not polarity sensitive.
1.12. ComponentSpecicWiring
CHECK VOLTAGE BEFORE CONNECTING ZONE CONTROL TRANSFORMER
(ZONE CTRL XFMR) LEADS TO THE ZONE CONTROL PANEL CONNECTIONS
VERSED; SWAP LEADS (AS SHOWN IN “C”) AND CONFIRM 0 VOLTS
IF 0 VOLTS (AS SHOWN IN “A”)
THEN POLARITY IS CORRECT
Figure 14. ConrmingTransformerPhasing(Polarity)isCorrect
1.12.1. Zone Control Transformer Phasing
Using two transformers on a single system—When the Harmony III zoning system
control panel is connected to a system that has its own transformer, the phasing
(or polarity) of the air handler transformer to the zone control’s add-on transformer
is extremely IMPORTANT because the zone control transformer powers the DS
circuit within the zone control and then connects to the air handler DS circuit.
The only two transformers that need correct phasing with their commons connected
are the zone control and air handler transformers. Check the phasing prior to
connecting the zone control transformer zone control panel’s connections. The

Lennox Harmony III Specifications

General

Brand	Lennox
Model	Harmony III
Category	Control Systems
Language	English