CSC-3000 Series Pneumatic VAV Reset Volume Controllers
5
Applications Guide, Rev G
REVERSE Reset Minimum and Maximum
NOTE: The reverse reset illustration above assumes
no relays are connected between the
thermostat and “T” port.
For Reverse Reset (RA thermostat for cooling or DA
thermostat for heating), perform the following steps:
1a. On the CSC-3000, disconnect the “T” port and
leave it open. Temporarily plug the tubing (but
do NOT plug the port).
1b.
Alternately,
instead of removing the tubing from the
T port, (temporarily) remove the plug from the CSC-
3000’s “G” port.
2. Adjust the LO STAT
∆
P (center dial) one
adjustment at a time until the desired
Maximum
airflow is read at the Magnehelic gauge and is
stable.
3a. Reconnect the thermostat tubing to the “T” port.
3b.
Or
reinstall the plug on the CSC-3000’s “G” port.
(See Step 1b.)
4. Adjust thermostat to call for full airflow (15 psi or
more at “T” port).
5. Adjust the HI STAT
∆
P (dial on right) one
adjustment (1/4 to 1/2 knob rotation) at a time
until the desired
Maximum
airflow is read at the
Magnehelic gauge and is stable.
NOTE: For more accuracy, temporarily relieve
the pressure before each dial adjustment.
Temporarily pull off the plug from the G
port (relieving the thermostat air pressure),
make the estimated amount of dial
adjustment, reinstall the plug, and wait
for the damper position to stabilize before
checking the flow.
6. Repeat Steps 1 through 5 to verify the settings to
be correct and fine tune if necessary.
NOTE: Adjust the dial no more than about a
half rotation at a time. After making any
adjustment, wait approximately ten seconds
while watching for motion in the damper
shaft. If no motion occurs, make the next
adjustment.
3a. Reconnect the thermostat tubing to the “T” port.
3b.
Or
reinstall the plug on the CSC-3000’s “G” port.
(See Step 1b.)
4. Adjust the thermostat to call for
minimum
airflow (15 psi or more at “T” port).
5. Adjust the HI STAT
∆
P (dial on the right) one
adjustment (1/4 to 1/2 knob rotation) at a time
until the desired
Minimum
airflow is read at the
Magnehelic gauge and is stable.
NOTE: For more accuracy, temporarily relieve
the pressure before each dial adjustment.
Pull off the plug on the G port (relieving
the thermostat air pressure), make the
estimated amount of dial adjustment,
reinstall the plug, and wait for the damper
position to stabilize before checking the
flow.
NOTE:
IF the HI STAT
∆
P Limit must be set at
“0” (zero minimum),
do not turn the HI
STAT
∆
P knob fully clockwise. The knob
will adjust past where a zero minimum is
reached. Turning the HI STAT
∆
P knob fully
clockwise will result in a negative reset
condition. This means that the controller
will get to zero before going through the
whole reset span. If a zero minimum is
required, adjust the HI STAT
∆
P knob
until the controller just begins to crack the
damper open, then back off slightly and
verify zero airflow.
6. Repeat Steps 1 through 5 to verify the settings to
be correct and fine tune if necessary.
Thermostat Pressure
Max. Airflow
Min. Airflow
Reset Start Point
• 3 psig: CSC-3021/3026
• 8 psig: CSC-3011/3016/3017/3025
• 10 psig: CSC-3023
Reset Span (5 psig)
(Cooling w/ RA Thermstat or
Heating w/ DA Thermostat)
