ZP2-HC-ESP Installation and Operation Instructions
1 Heat / 1 Cool - Auto Changeover
First Call Priority - Time Share
with Integrated ESP Static Pressure Module
OVERVIEW:
The ZP2-HC-ESP is a residential/light commercial
zone control panel that includes integrated ESP
static pressure control logic designed to eliminate
the need for a conventional bypass damper when
used with 3-wire zone dampers.
SEQUENCE OF OPERATION:
The panel allows a single HVAC unit to have up
to two separate zones. Each zone is controlled
by its own thermostat. When a zone thermostat
calls for heating or cooling, the zone not calling
will have its dampers powered closed, and the
zone calling will have its dampers powered
opened. The heating or cooling equipment will
also be brought on.
As zone dampers open and close, the ZPA-SPS
Static Pressure Sensor continuously monitors
the system static pressure. If the static pressure
goes above the static pressure setpoint, the
panel will send a signal to the non-calling zone
damper to start to open to a point where the
static pressure setpoint is maintained. The SPS
LED will come on with the non-calling zone LED
until the static pressure reaches setpoint. The
small amount of air allowed to bleed into non-
calling zone eliminates air noise and assures
proper airflow through the HVAC system. This
also prevents coil freeze up and high
temperature issues. When all calls are
satisfied, all zone dampers will go to the full open
position provided none of the thermostats are
calling for ventilation mode. If opposite calls take
place, 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
zones being served (heating or cooling) have 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:
A 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
(adjustable) and low (fixed) 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) 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. In cooling
mode, a 3 minute time delay is activated to
prevent short cycling of the equipment.
VENTILATION MODE:
Zone ventilation is established by the individual
zone thermostat fan setting. When no calls are
taking place, any thermostat set in the fan AUTO
mode will not receive ventilation air and its zone
damper will be closed. Any zone thermostat set in
the fan ON mode will receive ventilation air and its
zone damper will be opened. Heating or cooling
calls take priority over ventilation mode. The ESP
function will continue to maintain the system static
pressure by modulating open the non-calling
ventilation zone as required.
POWER REQUIREMENTS:
The panel is powered by a single 24VAC, 40VA
transformer. Never use the equipment
transformer.
1
SPEED UP
3
= 1
SEC
MIN
..
.
ON
OFF
3 AMP
3 AMP
1 2
..
.
ON
OFF
