System Operation - Lennox Harmony II Zone Control System Installation Instructions Manual

System Operation

This section describes how to operate the Harmony
trol panel and how the system reacts to each operation.
A−Zone Thermostats
Table 2 shows how the Harmony
prets zone thermostat inputs. The control center distin-
guishes between heat pump and heat/cool thermostats by
looking at how the INDOOR UNIT jumper is set on the con-
trol center.
Cool / Heat / Auto−Changeover Modes
Zone thermostats send a heating or cooling signal to
D
®
the Harmony II control center.
The thermostat servicing zone 1 is called the master
D
thermostat. Remaining thermostats are called zone 2
thermostat, zone 3 thermostat, and zone 4 thermostat.
Conventional thermostats with switching subbases are
®
used with the Harmony
may be standard or auto-changeover type. It does not mat-
ter how the thermostats are set; they should be simply set
for the level of comfort desired.
Gas heating (G32V/G21V/GSR21V) systems: Standard
heat/cool thermostats are used.
Heat pump systems: Heat pump heat/cool thermostats are
used.
For example, one thermostat may be set for cooling and
the others set for heating. If auto-changeover thermostats
are used, any or all of the thermostats may be set for auto-
changeover. The best efficiency will be maintained if all
zone thermostats are set with the setpoint close to one
another. This will minimize the number of changeovers the
system will have to initiate in order to satisfy an opposing de-
mand.
Fan On / Auto Mode
Zone thermostat indoor blower control is disconnected
D
and performs no function.
Indoor blower On / Auto selection is made at the Harmony
II control panel.
The service light in the master thermostat is connected
D
to the outdoor unit. The light is turned on when the
compressor in the outdoor unit needs servicing. The
service light in the remaining zone thermostats is dis-
connected.
Service Light (Heat pump only)
Emergency Heat (Heat pump only)
The emergency heat switch in any thermostat does not
D
allow the compressor in the outdoor unit to operate in
response to a thermostat heating demand. The indoor
unit supplies all of the heat. The emergency heat light
is turned on when the switch is engaged, and the auxil-
iary source is used to satisfy the heating demand in that
zone. The emergency heat switch in the remaining
zone thermostats provides similar a function.
®
II control center inter-
II control system. The thermostats
D When the emergency heat switch is turned on (any
zone thermostat), the auxiliary source is used to satis-
® fy heating demand in that zone.
II con-
Harmony
Thermostat Output
O W
Off Off
Off Off
Off On
Off On
On Off
On Off
On On
On On
B−Harmony
Auto−Changeover Modes
Cool, heat, or auto selection on the control panel deter-
D
mines what type of thermostat demand will be satisfied.
Heating Mode
When the user selects the Heat mode at the control
D
panel, the zone control system will only respond to
heating demands from the zone thermostat(s).
Heat modulation and regulation is coordinated between
the Harmony
or blower coil). When heating demands are satisfied, air is
delivered to the last demanding zone until the furnace has
cooled. If the system is operating in Fan-On mode and
heating demands have been satisfied, air is delivered to
the last demanding zone until the furnace has cooled. All
dampers then open and air circulates to all zones.
Cooling Mode
®
When the user selects the Cool mode at the control
D
panel, zone control system will only respond to cooling
demands from the zone thermostat(s).
When the system is in Cooling, the system responds to
cooling demands from any zone thermostat. The only
dampers to remain open are those supplying air to the de-
manding zone(s); all other dampers will close. The blower
operates at a speed determined by the position of the CFM
selection jumpers located on the control center.
On two−speed condensing units, selection between high
speed or low speed is determined by the discharge air tem-
perature. The normal speed change delay (located inside
the two-speed unit) applies. On two-speed and single−
speed applications, if the discharge air temperature cross-
es a minimum operating temperature, the compressor
cycles off (to protect from freeze-up). The compressor is
protected against short cycling by a five−minute time delay.
Page 27
Table 2
®
II Thermostat Input Interpretation
G32V/G21V G32V/G21V
Gas Heat Systems
Y
Off No Demand
On Cooling Demand
Off Heating Demand
On Error Code #10
Off Error Code #10
On Error Code #10
Off Error Code #10
On Error Code #10
®
II Control Panel Cool / Heat /
®
II control panel and the indoor unit (furnace
CB31MV Heat CB31MV Heat
Pump System
No Demand
Compressor
Heating Demand
Em. Heat
Compressor and
Auxiliary Heat
No Demand
Cooling Cooling
Demand
Error Code #10
Error Code #10