Installation and Maintenance Manual

Unit Start-Up Procedures
176 RLC-SVX09H-EN
Figure 79. RTUD Stopped to starting
RTUD Sequence of Operation Stopped to Starting
Stopped
Or
Run
Inhibit
Chiller Mode
Set to Auto
Auto
Energize Evaporator Water Pump Relay
Confirm Evaporator Water Flow Within 20 minutes
(6 Sec Filter)
Oil Heaters Always Energized When Respective Compressors
Are De-Energized
Call for Cooling (adj
Differential to Start is met)
Start Command to Lead Compressor*
* Lead Compressor (and its lead circuit) determined by staging algorithm
and “fixed staging” or “balanced wear” selection. If “balanced wear”
then compressor with least wear (10* starts + hours) is lead. If “fixed
staging” Cprsr 1A is always lead and Cprsr 2A is always lag. Staging
order is also influenced by
lockouts, restart inhibit, or diagnostics
present and will also obey priority staging rule: Any cprsr running but
not step loaded, has priority to either step load or to unstage (turn off).
Set Condenser Fan’s Pre-Flow % per Outdoor Temperature
Confirm
Presence of Oil
(0 to 2 mins)
Pre-Position EXV of
Lead Circuit
Energize Unload
Solenoid of Lead Cprsr
Energize Oil Return Fill
Solenoid of Lead Circuit
EXV stroke to
Preposition
0-20 sec
Energize Oil Return Drain
Solenoid of Lead Circuit
Send Start Command to Lead Compressor
Enforce Restart Inhibit Timer
(0 to 5 mins)
Confirm Evaporator Water Flow
(6 Second Filter)
Check Evap Pressure for
Low Pressure Cutout
Waiting
to Start
Waiting
to Start