DuroZone
SMZ-AC WIRING INSTRUCTIONS PAGE 4
SMZ-AC OPERATION
The SMZ-AC is a simple autochangeover zoning system incorporating individual thermostats and zone dampers to provide
comfort and economy.
The SMZ-AC is a first call - first served system, ie. If a zone calls for cooling, heating calls are locked out and the system will
satisfy all cooling calls. When satisfied the system will then switch to heat and satisfy those calls. When all zones are satisfied,
heating and cooling, each zone damper will be in the position set by the Damper Switch, (see below). If any zone calls, that
damper will open, or remain open, and all others will close. Should another zone call, for the same equipment as the first zone
to call, its corresponding damper will open. Upon satisfaction of the zone (s) all dampers will return to the position set with
the Damper Switch, (see below).
With a call in the heat mode, “R” makes to “W” in the equipment section, activating the furnace relay. The fan will be con-
trolled by the fan limit switch in the furnace.
With a call in the cool mode, “R” makes to “Y” activating the Compressor and “R” makes to “G”, activating the fan and “R”
makes to “O” activating the changeover valve if using a heat pump.
When the fan switch on the Zone One Sub-Base is in the “on” position, “R” makes to “G” and the fan provides constant air
circulation.
NOTE: If all damper switches are set in “closed”, “(C)” position, the fan will not operate in the “Fan On”
position.
DAMPER SWITCHES
The SMZ-AC Zone System is equipped with individual zone damper control switches. These switches are located to the left of
the zone relays; one switch per zone. These switches will allow a zone damper to remain in either the open or closed position
when the system board is at rest. The SMZ-AC allows the installer or home owner to choose the position of his system’s damp-
ers. This feature can inhibit migration of air into spaces not desired, for seasonal purposes, or when a zone is not in use.
The SMZ-AC Zone System has a built-in safety feature. At least one zone damper switch must be in the open position for the
“fan on” switch on the master thermostat to be operational. If all switches are set to “closed” (c), the constant fan circuit is
disabled. This safety feature removes the possibility that the air handler could be damaged due to cavitation, or by a restricted
air distribution system.
SMZ GAS/ELECTRIC JUMPER
Your SMZ panel includes a jumper block labeled JP1. The purpose of this jumper is to configure the operation of the fan for
normal gas /oil heating equipment or for electric heating equipment.
When Placed in the “G” position (default) the fan is controlled by the equipment in the heat mode (conventional operation).
When Placed in the “E” position the fan will come on immediately with the call for heating (electric heat operation).
ORDERING INFORMATION
Duro Zone’s SMZ Panels can be ordered for a variety of applications.
35235:
JTZ-HPSW -1 JTZ-HP Panel configured for three zone heat pumps.
35226:
SMZ-2 SW -1 SMZ-SW Panel configured for two zones.
35227:
SMZ-3 SW -1 SMZ-SW Panel configured for three zones.
35228:
SMZ-4 SW -1 SMZ-SW Panel configured for four zones.
35229:
SMZ-AC -1
SMZ-SW Panel configured for three zone autochangeover.
Damper is closed
when zone is satisfied.
Damper is open
when zone is satisfied.
O
C
O
C
JP1
G
E
Gas Mode - Normal operations. (Default Settings)
Electric Mode - Fan comes on immediately with heat call.
G
E