Trane Optimus RTHD - No Load Start Sequence; Operating Limit Conditions

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RTHD-SVX01L-EN
No Load Start
This diagram shows a pre-start sequence with the Start
Sequence Type set to 'No Load'.
Figure 38. Sequence of events: no load start
Enforce Restart
Inhibit Timer
(0 to 30 mins)
Confirm Condenser
Water Flow
(6 Second Filter)
Stopped
Or
Run
Inhibit
Removal of all of the following:
Auto
Evap Leaving Water
Temp Above the Diff to
Stop
Waiting
to Start
Starting
Compressor
Energize Evaporator
Water Pump Relay
Energize Condenser
Water Pump Relay
Confirm Evaporator Water
Flow Within 20 minutes
seconds (6 Sec Filter)
Confirm Condenser Water
Flow Within 20 minutes
(6 Sec Filter)
Pre-Position EXV
Waiting
to Start
Oil Heater always energized
when compressor is de-
energized
Confirm Evaporator
Water Flow
(6 Second Filter)
Energize Unload
Solenoid
Confirm Presence of Oil
With Optical Oil Sensor
(0 to 2 mins)
Waiting
to Start
Condenser
Water Pump
Pre-Run
Waiting
to Start
Enforce 'Cond
Pmp Strt Delay'
(0 to 300 Sec)
(0 to 30 mins)
Enforce 'Cprsr
Strt Delay'
(0 to 300 Sec)
Waiting
to Start
External Stop
Local Stop
Tracer/BAS Stop
Limit Conditions
Symbio™ 800 will automatically limit certain operating
parameters during startup and run modes to maintain
optimum chiller performance and prevent nuisance
diagnostic trips. These limit conditions are noted in
Table 15. Limit conditions
Condition Description
Running- limited The chiller, circuit, and compressor are currently running, but the operation of the chiller/compressor is being actively limited
by the controls. Further information is provided by the sub-mode.
Condenser Pressure Limit The circuit is experiencing condenser pressures at or near the condenser limit setting. The compressor will be unloaded to
prevent exceeding the limits.
Low Evaporator Refrigerant
Temperature Inhibit
The circuit is experiencing saturated evaporator temperatures at or near the Low Refrigerant Temperature Cutout setting.
The compressors will be unloaded to prevent tripping.
Capacity Limited by Low Liquid
Level
The circuit is experiencing low refrigerant liquid levels and the EXV is at or near full open. The compressor will be unloaded
to prevent tripping.
Current Limit The compressor is running and its capacity is being limited by high currents. The current limit setting is 100% RLA (to avoid
overcurrent trips).
Phase Unbalance Limit The compressor is running and its capacity is being limited by excessive phase current unbalance.
Start-Up and Shutdown