Start-Up and Shutdown
68
RTAF-SVX001K-EN
Normal Shutdown to Stopped or Run Inhibit
The figure below shows the Transition from Running
through a Normal (friendly) Shutdown. The Dashed lines
on the top attempt to show the final mode if you enter the
stop via various inputs.
Figure 46.
Sequence of events: normal shutdown to stopped or run inhibit
*
Operational Pumpdown is required if the Outdoor Air
Temperature is less than 50F, or the Entering Evaporator Water
Temperature is greater than (outdoor air temperature – 10°F). With
AFD, compressors will be at max speed for operational
pumpdown.
**Operational Pumpdown: See Satisfied Setpoint Operational
Pumpdown sequence diagram for specific criteria
***
Automatic evaporator isolation valve control will close valve if
Outdoor Ambient Air Temperature at circuit shutdown is less than
evaporator leaving water cutout setpoint plus 3°C.
The maximum allowed time for Operational Pumpdown is: Max
pumpdown time =setting x number of compressors configured on
the circuit.
Note: If Free Cooling is active, the last stage of cooling to turn off
will be Free Cooling.
/
//
6 1
// 2/
//
2 2
// 012 - 8/
//
8 1
// 5/
//
5 2
// 012
Shutting Down
Running Circuit Modes: Shutting Down
SubMode: Operational Pumpdown
*
8/
8
8 15/
5
5 2012
12/
2
2 11/
1 2012
6/
6
6 13/
3
3 2012
Operational Pumpdown
(See max allowed time below)
Fully Close EXV
Perform Operational
Pumpdown for All
Running Circuits if
Required
*
IF
*
Close EXV
(0 to 25 Seconds)
2
2
0
0
12
6/
6
6 12/
2
2 2012 -12/
2
2 11/
1 2012
Check for
Normal Pumpdown
Termination Criteria Met
**
6/
/
6
6 1
1
1
1
1
//
5
5
5
5/
/
5
2
2
2
2
2
2
//
0
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
2
2
2
2
2
2
2
No Pumpdown Required
Pumpdown
Required
Evaporator Pump Off Delay
(Adjustable 1 to 30 Minutes)
Send Stop Command to
All
Running Compressors
Energize All Heaters
Fully Close Both EXVs
Turn Off All Running
Circuits Condenser Fans
De-Energize Evaporator
Water Pump Relay
Stopped
or
Run Inhibi
One or
More
Circuits
Running
Normal Pumpdown Termination
**
Criteria is Met for All Circuits
Local Stop
Chiller Level Diagnostic – Normal Shutdown Latched
Chiller Level Diagnostic – Normal Shutdown Nonlatched
Building Automation System Stop
External Auto-Stop
8
r
r
i
i
/
a
a
8
a
a
1
a
a
//
a
a
5
i
i
s
s
/
s
s
5
s
s
2
s
s
//
s
s
0
M
M
1
M
M
2
e
e
-
t
t
1
f
f
o
o
0
o
o
/
r
r
0 1
r
r
A
A
//
r
r
A
A
/
A
A
l
l
A
A
2
l
l
//
l
lll
0
C
C
C
C
2
i
i
r
r
Shutting Down
Circuit Modes:
Auto
10/
0 1
// 6/
6
6 2
// 012 - 12/
2 1
// 1/2
// 012
Stopped or Run Inhibit
Circuit Modes:
Stopped or Auto
10/
0
0 17/
7
7 2012
Automatic Evaporator
Isolation Valve control
may close valve
Economizer – EEV and
port loader close
