Johnson Controls RW Series - Sequence of Operation

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RW SERIES REVERSIBLE CHILLER INSTALLATION MANUAL
Power Fail Restart
When the controller is first powered up, the outputs will be
disabled for a random start delay. The delay is provided to prevent
simultaneous starting of multiple heat pumps. Once the timer expires,
the controller will operate normally.
Random Start Delay
This delay will be used after every power failure, as well as the first
time the compressor is started after the control exits the unoccupied
mode or the emergency shutdown mode. The delay should not be
less than 1 second and not longer than 120 seconds. If the control is
in test mode the random start delay will be shortened to 5 seconds.
Lead Compressor Start Delay Time
The Lead Compressor Fixed On Delay Time will ensure that
the lead compressor output is not enabled for 90 seconds after
the control receives a call to start the compressor. This delay is
adjustable from 30 – 300 seconds over a BAS or a MUI. If the
control is in test mode the Lead Compressor Start Delay Timer will
be shortened to 5 seconds.
Lag Compressor Start Delay Time
The Lag Compressor Fixed On Delay Time will ensure that the lag
compressor output is not enabled for 90 seconds after the control
receives a call to start the compressor. This delay is adjustable
from 30 – 300 seconds over a BAS or a MUI. If the control is in
test mode the Lag Compressor Start Delay Timer will be shortened
to 5 seconds.
Compressor Minimum On Delay
The compressor minimum on delay will ensure that the compressor
output is enabled for a minimum of five (5) minutes each time the
compressor output is enabled. This will apply in every instance
except in the event the high pressure switch is tripped, freeze
protection, or emergency shutdown then the compressor output will
be disable immediately.
Compressor Minimum Off Delay Time
The compressor minimum off time delay will ensure that the
compressor output will not be enabled for a minimum of five (5)
minutes after it is disabled. This allows for the system refrigerant
pressures to equalize after the compressor is disabled.
Sequence of Operation
Compressor Lead/Lag
Compressor lead/lag is a standard part of the FX10 control system.
The unit is shipped from the factory with lead/lag enabled. Lead/lag
can be activated through the unit mounted user interface.
Heating Cycle
The control will run the unit in heating mode when there is a
command on the O/B terminal on the terminal board.
Cooling Cycle
The control will run the unit in cooling mode when there is no
command on the O/B terminal on the terminal board.
MUI Alarm History Reporting
If a fault occurs the fault will be recorded in history for display on
the medium user interface in the History Menu. Each fault type will
be displayed in the history menu with a number between 0 and 3. A
reading of 3+ will mean that fault has occurred more than three times
in the past. The history menu can be cleared with a power cycle only.
Alarm date and time are not included in the history.