ZP3-HCMS Installation and Operation Instructions
(Versions 301) 2 Heat / 2 Cool - Auto Changeover
First Call Priority - Time Share
Sequence of Operation:
T
he ZP3-HCMS is a residential / light commercial
zone control system that allows a single HVAC
unit to have up to three separate zones. Each
zone is controlled by its own space thermostat
and motorized zone damper. If a zone thermostat
calls for heating or cooling, the zones not calling
will have their dampers powered closed, and the
zone calling will have its damper opened. The
heating or cooling equipment will also be brought
on at the same time. When the zone calling is
satisfied, the heating or cooling equipment turns
off. If one zone calls for heating and another zone
calls for cooling, the first zone to call receives
priority. When the first call is satisfied, the system
will changeover and take care of the opposite call.
If a zone being served (heating or cooling) has not
been satisfied within 20 minutes while an opposite
call is taking place, the system will changeover.
When the zone is satisfied or 20 minutes has
elapsed, the system will again changeover if an
opposite call exists. This is referred to as Auto
Changeover - First Call Priority - Time Share. In
the event of a tie, cooling will receive priority.
High and Low Limit Protection:
The ZPA-DTS Discharge Temperature Sensor
should be mounted on the discharge air plenum
of the HVAC unit and wired to the DA terminals on
the panel. The sensor is used for both high and
low limit protection. The high limit setting can be
adjusted using the two slide switches located on
the panel. (See switch location and settings on
page 2) The low limit is fixed at 45° F. When the
discharge air temperature rises above the high
limit setting or falls below the low limit setting, the
panel will cycle the equipment off while the fan
continues to run. The LIMIT LED blinks when
high or low limit is reached.
Ventilation Mode:
Zone ventilation is established by the individual
zone thermostat fan setting. Any thermostat set
in the fan AUTO mode will not receive ventilation
air when there are no heating or cooling calls.
Any thermostat set in the fan ON mode will
receive ventilation air whenever there are no
heating or cooling calls.
Power Requirements:
The ZP3-HCMS requires a separate 24 Vac
transformer. A 40 VA transformer will power the
panel and up to four (4) dampers. A 75 VA
transformer will power the panel and up to seven
(7) dampers. If more than three (3) dampers for
an individual zone are required, a RY-1-HB relay
should be used with an additional properly sized
transformer. iO Systems HD-XXXX rectangular
and D-XX round dampers are powered closed /
spring return open. Damper actuators are rated
at 10 VA. If 3-wire dampers (powered open /
powered closed) are installed, VA ratings will
vary depending on the damper actuator used.
Wiring:
All wiring should be conventional 18 gauge
thermostat wire. Thermostats and zone dampers
may be located up to 300 feet from the
ZP3-HCMS panel.
HVAC Controls
