Johnson Controls ZL Series Installation Manual page 62

energizes the compressor and condenser fan motor
only.
When the thermostat has been satisfied, it de-
energizes Y1. If the compressor has satisfied its
minimum run time, the compressor and condenser
fan are de-energized. Otherwise, the unit operates
the cooling system until the minimum run times
for the compressor are completed. After the
compressor de-energizes, the blower is stopped
following the elapse of the fan off delay for cooling,
and the economizer damper goes to the closed
position. If the unit continues fan operation, the
economizer damper goes to the min. position.
Economizer with dual enthalpy
sensors
The operation with the dual enthalpy sensors is
identical to the single sensor except that a second
enthalpy sensor is mounted in the return air. This
return air sensor allows the economizer to choose
between outdoor air and return air, whichever has
the lowest enthalpy value, to provide maximum
operating efficiency.
Economizer with power exhaust
A unit equipped with an economizer (single or
dual enthalpy) and a power exhaust operates
as specified above with one addition. The power
exhaust motor is energized 45 seconds after the
actuator position exceeds the exhaust fan setpoint
on the economizer control. The R to G connection
provides minimum position but does not provide
power exhaust operation.
Motorized outdoor air dampers
This system operation is the same as the units with
no outdoor air options with one exception. When
the R to G circuit is complete, the motorized damper
drives open to a position set by the thumbwheel
on the damper motor. When the R to G circuit is
opened, the damper spring returns fully closed.
Each cooling system is monitored for operation
outside of the intended parameters. Errors are
handled as described below. All system errors
override minimum run times for compressors.
Note: The following components are needed
to access the control points in the Smart
Equipment™ control.
1. Local LCD on Unit Control Board.
OR
62 Installation Manual ZL Series 7.5- 12.5 Ton 60 Hertz R-410A
2. Mobile Access Portal (MAP) Gateway
(Portable).
High-pressure limit switch
During cooling operation, if a high-pressure limit
switch opens, the UCB de-energizes the compressor,
initiates the ASCD (anti-short cycle delay), and stops
the condenser fans. If the call for cooling is still
present at the conclusion of the ASCD, the UCB re-
energizes the halted compressor.
If a high-pressure switch opens three times within
two hours of operation, the UCB locks out the
compressor.
Low-pressure limit switch
The low-pressure limit switch is not monitored
during the initial 30 seconds of a cooling system's
operation. For the following 30 seconds, the UCB
monitors the low-pressure switch to ensure that
it closes. If the low-pressure switch fails to close
after the 30-second monitoring phase, the UCB de-
energizes the compressor, initiates the ASCD, and
stops the condenser fans.
When the low-pressure switch is proven (closed
during the 30-second monitor period described
above), the UCB monitors the low-pressure limit
switch for any openings. If the low-pressure switch
opens for greater than 5 seconds, the UCB de-
energizes the compressor, initiates the ASCD, and
stops the condenser fans.
If the call for cooling is still present at the conclusion
of the ASCD, the UCB re-energizes the halted
compressor.
If a low-pressure switch opens three times within
one hour of operation, the UCB locks out the
compressor.
Evaporator low limit
The evaporator low limit sensor (EC1) is located
on the suction line at the evaporator coil. During
cooling operation, if the evaporator low limit sensor
detects a temperature below 26°F (default), the UCB
de-energizes the compressor, initiates the ASCD,
and stops the condenser fans. If the call for cooling
is still present at the conclusion of the ASCD, the
UCB re-energizes the halted compressor.
Johnson Controls Ducted Systems
- Source 1 P/N S1-JC-MAP1810-OP
- MAP Gateway Quick Start Guide P/N
24-10737-16
- MAP Gateway Instruction P/N
24-10737-8