Chiller Data; Hardwired Chiller - Communication Loss Control At The Chiller - McQuay MicroTech II Operation Manual

Alarm Alarm Alarm Message
Type Priority
Chiller X In Alarm

Chiller Data

Hardwired chillers have less information available at the CSM user interface or offered to a BAS than MicroTech II
chillers communicating with the CSM on the dedicated L
(see Table 29). The following list represents data points available on the CSM user interface from a chiller connected to
the CSM via hardwiring:
Analog Data
Actual Chiller Capacity (% RLA)
Chiller Evaporator Leaving Water Temperature (optional)
Chiller Condenser Leaving Water Temperature (optional)
Chiller Capacity Limit
Active Chiller Setpoint
Digital Data
Chiller Run Mode
Chiller Run Enabled/Disabled
Chiller Evaporator Flow Status
Chiller Condenser Flow Status
Chiller Limited
Alarm Digital Output
Note: Two temperature sensors can be installed to show the leaving evaporator water temperature and the leaving
condenser water temperature (on water-cooled units) of each hardwired chiller. These temperatures are optional because
they are not used by the CSM logic (or by the chiller) for any control purposes. If one or both of these sensors are installed
they will be displayed on the Chiller Status screen and can be passed by the CSM to an optional BACnet or Modbus
building automation system for display and/or monitoring purposes.

Hardwired Chiller - Communication Loss Control at the Chiller

If a hardwired chiller loses communication with the CSM, the chiller can be set up to maintain last setpoints or to shut
down.
If a hardwired chiller's Receive Heartbeat property is set to zero (default), the state of a hardwired chiller's Enable
Command and Cool Setpoint will remain at their current settings if communications are lost between the CSM and the
hardwired chillers remote I/O module. For example, if the chiller is enabled with a cool setpoint of 44 °F at the time
communications are lost, it will remain enabled at 44 °F until communications is restored.
If a hardwired chiller's Receive Heartbeat property is set to a value greater than 200 seconds, the hardwired chiller will be
disabled if communications are lost between the CSM and the hardwired chiller's remote I/O module.
The ability to enable a chiller in the event of communication loss is not available on hardwired chillers. This feature is
available on MicroTech II L
OM 780-2
Indication
At least one alarm in chiller X is active. X could be any
chiller commissioned to the CSM. For a description of the
current active alarms on a particular chiller, see it's
"Alarm" line on the Chiller Status screen or that chillers
alarm log on the Misc screen
W communicating chillers but not on hardwired chillers.
ON ORKS
W network. Chiller alarm descriptions are also limited
ON ORKS
Reset
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