Stopped To Starting - Trane Ascend ACR C Series Installation, Operation And Maintenance Manual

Start-up and Shutdown

Stopped to Starting

The following diagram shows the timing from a stopped
mode to energizing the first compressor. The shortest
allowable time would be under the following conditions:
• No motor restart inhibit time left from subsequent starts
Figure 30. Sequence of events: stopped to starting
Auto Mode commanded Auto Mode commanded
by Front Panel or BAS by Front Panel or BAS
Stopped Stopped
Stop Stop Stop
Or Run Or Run
Inhibit Inhibit
Confirm Evaporator Water Flow Confirm Evaporator Water Flow
(6 Second Filter) (6 Second Filter)
84
Auto Auto Auto
Enforce Restart Inhibit Timer Enforce Restart Inhibit Timer
(0 to 1 minute) (0 to 1 minute)
Energize Evaporator Energize Evaporator
Water Pump Relay Water Pump Relay
Confirm Evaporator Water Confirm Evaporator Water Confirm Evaporator Water
Flow Within 20 minutes Flow Within 20 minutes Flow Within 20 minutes
(6 Second Filter) (6 Second Filter) (6 Second Filter)
EXV remains closed EXV remains closed
Oil Heaters Energized
when all Compressors on
Circuit are De-energized
• Evaporator water flow occurs quickly with pump on
command
• Need to cool (differential to start) already exists
The above conditions would allow a compressor to start in
about 20 seconds.
Call for Call for Cooling** Cooling**
(Differential to Start is met) (Differential to Start is met)
Waiting Waiting Waiting
Auto Auto Auto
To Start To Start To Start
Wait for Need Wait for Need Confirm Confirm
To Cool To Cool Presence of Oil Presence of Oil
(Diff to Start) (Diff to Start) (0 to 90 seconds) (0 to 90 seconds)
Confirm Presence Confirm Presence Confirm Presence Confirm Presence
of Oil Within of Oil Within of Oil Within of Oil Within
90 Seconds 90 Seconds 90 Seconds 90 Seconds
* * Lead Compressor (and its lead circuit) is determined by staging algorithm – Lead Compressor (and its lead circuit) is determined by staging algorithm –
"Balanced", "Circuit 1 Lead", or "Circuit 2 Lead" selection – also influenced "Balanced", "Circuit 1 Lead", or "Circuit 2 Lead" selection – also influenced
by lockouts, restart inhibit, or diagnostics present. by lockouts, restart inhibit, or diagnostics present.
On a manifolded circuit, GP4 will be the first to start and last to stop; GP2 will On a manifolded circuit, GP4 will be the first to start and last to stop; GP2 will
not run by itself. not run by itself.
**Note: If Free Cooling is active, it will be the first stage of cooling to stage on. **Note: If Free Cooling is active, it will be the first stage of cooling to stage on.
Waiting Waiting Waiting
To Start To Start To Start
Fans pre-start, EXV Fans pre-start, EXV
moving to moving to
Send Start Command Send Start Command
Preposition Preposition
to Lead to Lead
0 to 25 Seconds, 0 to 25 Seconds,
Compressor Delay Time Compressor Delay Time
has expired has expired
Pre-Position EXV of Pre-Position EXV of Pre-Position EXV of
Lead Circuit Lead Circuit Lead Circuit
Check Evap Pressure for Check Evap Pressure for Check Evap Pressure for Check Evap Pressure for
Low Pressure Cutout Low Pressure Cutout Low Pressure Cutout Low Pressure Cutout
Transition to Transition to
Running Running
Compressor* Compressor*
Start Control of Start Control of
Condenser Fan Flow Condenser Fan Flow
AC-SVX003A-EN