LCD display
The board has an easy to read, built-in LCD display and easy to use buttons and a navigation
joystick. These features allow the user to quickly navigate the menus that display the unit status,
options, current function, supply, return and outdoor temperatures, fault codes, and other
information.
Safety monitoring
The control monitors the following values:
•
Outdoor, supply, and return air temperatures
•
The high and low pressure switch status on the independent refrigerant circuits
•
The voltage supplied to the unit. If the low voltage is due to a brown out, or some other
electrical issue occurs, the control protects the unit
Low ambient
With a low ambient damper kit or VFD on the condenser installed, an integrated low ambient
control allows units to operate in the cooling mode down to 0.0°F outdoor ambient. Optionally,
when the OAT is low and with the airside economizer option installed, the control board can be
programmed to lock out the compressors.
Anti-short cycle delay (ASCD) protection
To assist compressor life, the standard control incorporates an ACSD. The compressor reliability is
further ensured by programmable minimum runtimes.
Fan delays
Fan on and fan off delays are fully programmable. Furthermore, the heating and cooling fan delay
times are independent of one another. All units are programmed with default values based upon
their cooling or heating capacity configuration.
Nuisance trip protection and three strikes
To prevent nuisance calls, the control board has three soft faults before a hard lock out operation.
The high/ low-pressure switch, anti-freeze protection, low voltage, or heating high limit must trip
three times within two hours before the unit control board locks out the associated compressor.
The LCD screen displays an alarm message.
Lead-lag
An integrated lead-lag option is available However, never enable it on DSH units. This option can be
selected on the unit control board. The default factory setup is always disabled.
Note:
Enabling lead-lag function will affect logic of DSV unit and disable unit operation.
Condensate overflow switch
A condensate overflow fault occurs when the condensate overflow switch opens for the first time,
as the switch is connected to the onboard shutdown (SD) contact. The compressor is shut down
regardless of minimum runtime. The ASCD is initiated and the alarm is tripped. The fan continues
to operate in its current state. The compressor re-energizes once the condensate overflow switch
closes, the ASCD has been satisfied, and a call for cooling is still present.
D-Series Vertical (DSV060C-300C) Air-Cooled Self-Contained Units, C Generation with Smart Equipment Controller
42
Johnson Controls
