Energy Recovery Ventilator; Sequence Of Operation; Low Voltage Protection; Outdoor Air Heating Lockout - York ECO2 YPAL 050 Installation & Operation Manual

ENERGY RECOVERY VENTILATOR

If the unit has an Energy Recovery Ventilator installed
the exhaust fan needs to operate any time the supply fan
is energized. This feature can be programmed to only
occur in the occupied mode or in both the occupied and
unoccupied mode.
The following parameters must be programmed to use
this feature:
"ERV ENABLED" – must be enabled using the
ECONOMIZER/EXHAUST tab of the Simplicity PC
software package.
If you want this feature to operate in the unoccupied
mode the following parameter must be enabled.
"ERV UNOCCUPIED FAN ENABLED"- must be
enabled using the ECONOMIZER/EXHAUST tab of
the Simplicity PC software package.

Sequence of Operation

In the occupied mode, anytime the supply fan is
energized the exhaust fan will also be turned on.
If "ERV UNOCCUPIED FAN ENABLED" is enabled
the exhaust fan will operate in either the occupied or
unoccupied mode when the supply fan is energized.
If the unit has a Exhaust Fan VFD, the output voltage
to the Exhaust Fan VFD will be the same as the voltage
output to the supply fan VFD.

LOW VOLTAGE PROTECTION

The Simplicity Elite control monitors the 24 VAC
low voltage level. Before the Simplicity Elite control
energizes a binary output to a contactor, it checks this
voltage level. If the voltage is equal to or less than
19.2 volts the control will not energize the output and
will fl ash an Alarm Code 35. If the voltage rises above
19.2 volts the control will close the output and resume
normal operation.
If the voltage drops below 16 volts with binary outputs
already energized, the control will open all the binary
outputs to the contactors and fl ash an Alarm Code 35.
If the voltage rises above 19.2 volts the Simplicity Elite
control will resume normal operation.
JOHNSON CONTROLS

OUTDOOR AIR HEATING LOCKOUT

This feature prevents the Simplicity Elite control
from operating in the heating mode when the outdoor
temperature is above this set point.
The set point for this feature is programmed through
the following parameter:
"OUTDOOR AIR TEMP HEATING LOCKOUT" – is
programmed using the HEATING SETUP tab in the
Simplicity PC software package.

HOT GAS BYPASS

Hot gas by pass is used to inject discharge gas into the
expansion valve distributor to artifi cially place a load on
the evaporator coil under a light load condition. This is
done to raise the suction pressure to keep the saturation
temperature of the refrigerant high enough to prevent
icing of the coil. An auxiliary contact on the condenser
fan, 7M- contactor, energizes the hot gas bypass valve
whenever the contactor is energized. The hot gas valve
monitors the suction pressure and will modulate to keep
the suction pressure above 55 PSIG.
All VAV units have a hot gas valve installed in the
number 1 compressor system.
on CV units. If the lead/lag option is enabled the
Simplicity Elite control needs to know the hot gas
option is installed. This is done through the following
programming parameter.
"HOT GAS BY PASS PRESENT ON COMPRESSOR #
1" - must be turned on using Parameter 79 under the
PROGRAM key on the Simplicity Elite control board
or under the COOLING SETUP tab of the Simplicity
PC software.

SPACE TEMPERATURE ALARM

When this feature is enabled, the Simplicity Elite
control monitors the space temperature. When the
space temperature continues to trend above or below
the programmed set point and the programmed time
has expired, the Simplicity Elite control will declare a
Space Temperature Alarm.
FORM 100.50-NOM6 (1207)
Hot gas is optional
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