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
19.2volts the control will not energize the output and will flash an Alarm Code 35. If the voltage rises above
19.2volts 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 flash an Alarm Code 35. If the voltage rises above 19.2 volts the Simplicity Elite control will resume normal operation.
FORM
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 artificially 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. Hot gas is optional on CV units. If the lead/lag option is enabled the Simplicity Elite control needs to know the hot gas 5 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.
JOHNSON CONTROLS | 95 |
