Johnson Controls 100 Series, Installation Operation & Maintenance

Page: 70 / 182

JOHNSON CONTROLS
70
FORM 100.50-NOM12
ISSUE DATE: 04/02/2019
SECTION 5 – SEQUENCE OF OPERATION
5 Volts
0 Volts
(Default = 65.0
°
F)
Supply Air Temp Rst
Voltage
(Volts DC)
Active SAT
Setpoint
SAT HIGH SETPOINT
(Default = 55.0 °F)
SAT LOW SETPOINT
LD12587
FIGURE 28 - ACTIVE SAT SETPOINT VERSUS SAT RESET VOLTAGE
• A current RAT that is equal to/below the RAT
setpoint for high SAT causes the active cool-
ing SAT setpoint to be the SAT high setpoint.
• A current RAT that is equal to/above the RAT
setpoint for low SAT causes the active cool-
ing SAT setpoint to be the SAT low setpoint.
• A current RAT that is between the RAT
setpoint for high SAT and the RAT setpoint
for low SAT causes the active cooling SAT
setpoint to be between the high SAT and low
SAT setpoints. See Figure 29 on page 71 .
3. Outside Air Temperature (OAT)
• This method uses built in logic that resets the
active SAT setpoint based on the current OAT.
• There is no VDC signal or BAS command
required to perform this sequence.
• The IPU board monitors the current OAT and
resets the active SAT setpoint as needed.
• A current OAT that is equal to/below the OAT
setpoint for high SAT causes the active cool-
ing SAT setpoint to be the SAT high setpoint.
• A current OAT that is equal to/above the OAT
setpoint for low SAT causes the active cool-
ing SAT setpoint to be the SAT low setpoint.
• A current OAT that is between the OAT
setpoint for high SAT and the OAT setpoint
for low SAT causes the active cooling SAT
setpoint to be between the high SAT and low
SAT setpoints. See Figure 30 on page 71 .
1. Hardwired
• This method uses built in logic that resets
the active SAT setpoint based on either a
0–5 VDC signal to CTB1 or a 0–5 command
from the BAS.
• To use the 0–5 command from the BAS, SAT
reset BAS must be User Enabled. SAT re-
set BAS can be found under the SERVICE
menu.
• A VDC signal or BAS command of 0 causes
the active cooling SAT setpoint to be the SAT
high setpoint.
• A VDC signal or BAS command of 5 causes
the active cooling SAT setpoint to be the SAT
low setpoint.
• A VDC signal or BAS command between
0–5 causes the active cooling SAT setpoint
to be between the SAT high and SAT low set-
points per Figure 28 on page 70 .
• When a fixed SAT setpoint is required,
choose this SAT reset sequence, and then set
the SAT high setpoint to the required value.
2. Return Air Temperature (RAT)
• This method uses built in logic that resets the
active SAT setpoint based on the current RAT.
• There is no VDC signal or BAS command
required to perform this sequence.
• The IPU board monitors the current RAT and
reset the active SAT setpoint as needed.