KMC Controls CSC 3000 Series User guide

CSC-3000 Series Pneumatic VAV Reset Volume Controllers 1 Applications Guide
Applications Guide
General Information ..................................................................................................... 2
CSC-3000 Series Overview............................................................................................................................................2
Mounting.......................................................................................................................................................................2
More Information..........................................................................................................................................................2
Connections ..................................................................................................................................................................3
Adjustments and Calibration .........................................................................................................................................4
Damper Action........................................................................................................................................................4
Determining the Type of Reset ................................................................................................................................4
Adjusting Minimums and Maximums ......................................................................................................................4
DIRECT RESET Minimum and Maximum.................................................................................................................4
REVERSE RESET Minimum and Maximum ...............................................................................................................5
Reset Start Point......................................................................................................................................................5
Reset Span...............................................................................................................................................................6
Troubleshooting.............................................................................................................................................................6
Maintenance..................................................................................................................................................................6
Pressure Independent Operation Principles...................................................................................................................7
Magnehelic Gauge to Airflow Rate Chart ......................................................................................................................8
Applications.................................................................................................................. 9
Cooling..........................................................................................................................................................................9
Cooling with Heating Valve .........................................................................................................................................10
Cooling with Heating P. E. ...........................................................................................................................................11
Dual Duct....................................................................................................................................................................12
Dual Duct, Constant Volume .......................................................................................................................................13
*(These instructions do not apply to the
CSC-3014 or the CSC-3501/3505.)
Pneumatic VAV Reset Volume Controllers
CSC-3000 Series*

CSC-3000 Series Pneumatic VAV Reset Volume Controllers 2 Applications Guide
NOTE: These controllers are used on single and
dual duct applications. When working on
dual duct applications, it may be necessary
to work on one duct at a time.
NOTE: Any sequencing with other controllers,
valves, or pneumatic-electric relays must
be done with the controller’s reset range,
NOT the actuator’s spring range.
General Information
CSC-3000 Series Overview
These CSC-3000 series reset volume controllers are
designed for use on heating or cooling systems with
(normally open or normally closed) VAV terminal
units and (direct or reverse acting) thermostats.
They are sub-master air velocity controllers. Each
is equipped with separate adjustment knobs for
minimum and maximum airow setpoints. Models
are available with various reset start points. A master
controller, typically a room thermostat, resets the
CSC between the minimum and maximum velocity
setpoints.
The universal design of the CSC-3000 series is
intended for new or replacement applications that
call for direct or reverse acting reset on normally
open or normally closed VAV terminal units.
Mounting
The CSC-3000 Series are position sensitive. They
must be mounted and calibrated in either the hori-
zontal or vertical plane.
1. As near to the ow sensor pickup as is feasible,
connect the mounting bracket to the mounting
surface with two self-threading screws in the two
3/16" (5 mm) mounting holes. Be sure to leave
enough room to make connections.
2. Insert the controller, face down, up, right or le.
The controller must be installed and adjusted in
the same plane or readjustment will be necessary.
More Information
For additional specications, see the Data Sheet for
these controllers.
This Application Guide does not apply (completely)
to the CSC-3014 (designed to work with CTC-2100
Thermostats) or the CSC-3501/3505 (Linear Volume
Reset Controllers). See their separate Data Sheets and
Installation Guides.
All dimensions are
in inches (mm).

CSC-3000 Series Pneumatic VAV Reset Volume Controllers 3 Applications Guide
CAUTION
Pneumatic devices must be supplied with clean,
dry control air. Any other medium (e.g., oil or
moisture contamination) will cause the device
to fail.
Connections
For all models of the CSC-3000 series, use 1/4" (5
mm) O.D. “FR” tubing on the following push-on
ings:
1. Connect the clean, dry, oil-free main air supply to
Port “M” (15 to 30 psig).
2. Connect the damper actuator to Port “B”.
3. Connect the thermostat output to Port “T”.
4. Connect the high pressure tap on the airow
sensor to Port “H”.
5. Connect the low pressure tap on the airow
sensor to Port “L”.
6. Check for proper connections. Make sure all
tubes are snug on their ings. If loose, trim the
end of the tubing and reconnect it to ensure there
are no leaks.
NOTE: Over time, the tube may stretch or develop
microcracks. Trim the end of tube back
to undamaged material and reconnect.
Replace the tubing if it is brile or
discolored.
NOTE: You can easily test for leaks with a squeeze
bulb to ensure there are no leaks at the
actuator diaphragm or ings.
7. Use a ow hood or “tee” a Magnehelic®(or
equivalent) dierential pressure gauge between
the controller and the ∆P pick-up to determine
airow rates.
Typical CSC-3011 Application and Connections
(These instructions do not apply to the CSC-3014 or the CSC-3501/3505.)
Magnehelic gauge and 0–30 psi
gauge in illustration added for
checkout and calibration purposes.

CSC-3000 Series Pneumatic VAV Reset Volume Controllers 4 Applications Guide
Adjustments and Calibration
Damper Action
The damper action is factory-set at Normally Open
(N.O.). To change to Normally Closed (N.C.), per-
form the following steps:
1. Loosen the damper selection screw.
2. Turn the selection dial clockwise until the “NC”
arrow aligns with the “DAMPER” arrow.
NOTE: Accuracy in the alignment of the arrows is
very important. Make this adjustment as
exact as possible.
3. Tighten the selection screw. Be sure the
screw is tight (2 to 4 in-lbs. of torque), but if
overtightened, the plastic will strip out.
DIRECT RESET Minimum and Maximum
Determining the Type of Reset
The following table shows when Direct Reset or
Reverse Reset is required. Determine the reset type
based on the temperature of the primary air entering
the VAV box and whether the thermostat in the space
is direct or reverse acting.
3 psig 8 psig 13 psig
Thermostat Pressure
Max. Airflow
Min. Airflow
Reset Start Point (8 psig)
Reset Span (5 psig)
Adjusting Minimums and Maximums
When adjusting the minimum and maximum airow
seings, the output responds slowly to changes in
the setpoint. Wait for the ow rate to stabilize aer
making an adjustment (usually 20 to 30 seconds) be-
fore making further adjustments. Also, if the damper
position is all the way closed or open when starting
this step, turn the adjustment one full turn, and then
wait 20 to 30 seconds for a change in the ow read-
ing of the Magnehelic gauge. If no change occurs
aer this time, repeat until the ow rate changes.
NOTE: The direct reset illustration above assumes
no relays are connected between the
thermostat and “T” port.
For Direct Reset (DA thermostat for cooling or RA
thermostat for heating), perform the following steps:
1. Adjust the thermostat to a seing that will cause
the output pressure to be as high as possible (15
psi or more). This can be done in the following
manner:
a. For Direct Acting thermostats, lower the
seing to the lowest possible seing.
b. For Reverse Acting thermostats, raise the
seing to the highest possible seing.
2. On the CSC-3000, disconnect the “T” port.
Temporarily plug the tubing. (Do NOT plug the
port.)
3. Adjust the LO STAT ∆P (center dial) one
adjustment (1/4 to 1/2 knob rotation) at a time
until the desired Minimum airow is read at the
Magnehilic gauge and is stable.
NOTE: If the LO STAT ∆P Limit must be set at
“0” (zero minimum), do not turn the LO
STAT ∆P knob fully clockwise. The knob
will adjust one and one-half turns aer a
zero minimum is reached. Turning the LO
STAT ∆P knob fully clockwise will result
in a negative reset condition. This means
that when the controller begins to reset at
the reset start point it must rst overcome
the negative adjustment and will not begin
to reset from “0” until a higher thermostat
reset pressure is reached. This negative
reset will also reduce the eective range
of the controller by reducing the low end
reset; narrowing the reset span. If a zero
minimum is required, adjust the LO STAT
∆P knob until the controller just begins
to crack the damper open, then back-o
one-quarter turn and verify zero airow.
(This is typically 2-1/2 knob rotations
counterclockwise from the fully clockwise
position.)
4. Reconnect the thermostat tubing to the “T” port.
This will put 15 PSI or more on the “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 airow is read at the
Magnehilic gauge and is stable.
6. Repeat Steps 2 through 5 to verify the seings to
be correct and ne tune if necessary.
Primary Air Thermostat Reset Type
Cooling DA Direct Reset
RA Reverse Reset
Heating DA Reverse Reset
RA Direct Reset

CSC-3000 Series Pneumatic VAV Reset Volume Controllers 5 Applications Guide
REVERSE RESET Minimum and Maximum
3 psig 8 psig 13 psig
Thermostat Pressure
Max. Airflow
Min. Airflow
Reset Start Point (3 psig)
Reset Span (5 psig)
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:
1. Adjust the thermostat to a seing that will cause
the output pressure to be as high as possible (15
psi or more). This can be done in the following
manner:
a. For Direct Acting thermostats, lower the
seing to the lowest possible seing.
b. For Reverse Acting thermostats, raise the
seing to the highest possible seing.
2. On the CSC-3000, disconnect the “T” port and
leave it open. Temporarily plug the open tubing.
3. Adjust the LO STAT ∆P (center dial) one
adjustment (1/4 to 1/2 knob rotation) at a time
until the desired Maximum airow is read at the
Magnehilic gauge and is stable.
4. Reconnect the thermostat tubing to the “T” port.
This will put 15 PSI or more on the “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 airow is read at the
Magnehilic gauge and is stable.
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 o slightly and
verify zero airow.
6. Repeat Steps 2 through 5 to verify the seings to
be correct and ne tune if necessary.
(Reverse) Reset Start Point Adjusted from 8 to 3 psig
Reset Start Point
The reset start point is the pressure from the
thermostat at which the controller begins to reset
from the LO STAT to the HI STAT seing.
Models of the CSC-3000 series come with reset
start points factory-set at 3, 8, or 10 psig. (See the
chart on the next page.) These are standard in most
applications and typically do not require adjustment.
If a reset start point is needed other than the default
seing, all models are eld adjustable between 0 and
10 psig. (If the reset start point is changed, the reset
span may need to be adjusted as well.) To adjust the
reset start point, carry out the following steps:
1. Put the thermostat pressure at the desired start
point pressure (e.g., 3 psig).
2. Remove rubber plug at the “G” port and read
pressure at “G” with a 0–30 psi gauge (requires
5/32" O.D. tubing).
3. With a small at-blade screwdriver, adjust
(counterclockwise to increase; clockwise to
decrease) the reset start point control (at the top
of the controller) until the pressure read at “G”
port is just beginning to move o zero (0) psig.
NOTE: If the controller does not respond correctly
aer all adjustments have been made, it
may be necessary to correct the reset span
adjustment.
3 psig 8 psig 13 psig
Thermostat Pressure
Max. Airflow
Min. Airflow
New Reset Start
Point (3 psig)
Old Reset Start
Point (8 psig)

CSC-3000 Series Pneumatic VAV Reset Volume Controllers 6 Applications Guide
Troubleshooting
The CSC-3000 series are position sensitive. Be sure
to mount the controller with the correct orienta-
tion. See the Mounting section. If the controller is
calibrated in a position other than the nal mounting
position, the calibration (minimum and maximum
ow limits) will be o.
The spring range of the actuator does not maer.
However, sucient main air is required to provide
the actuator with enough force to operate the damp-
er/linkage. Also, there can be no leaks in the actuator
since even small leaks can cause the actuator to not
stroke. You can easily test for leaks with a squeeze
bulb to ensure there are no leaks at the actuator dia-
phragm or ings.
Any sequencing with other controllers, valves, or
pneumatic-electric relays must be sequenced with
the controller’s reset range, not the actuator’s spring
range.
These controllers are typically used on single-duct
applications but may be found in dual-duct applica-
tions. When working on dual-duct applications it
may be necessary to work on one duct at a time.
Reset Span
The reset span is the thermostat’s eective reset
range for the controller. A reset span of 5 psig means
that it will take a 5 psig pressure change measured
from the reset start point to reset the ow rate of the
VAV box.
Maintenance
No routine maintenance is required. Each compo-
nent is designed and manufactured for reliability
and performance. Careful installation and use will
ensure long-term dependability.
CAUTION
Pneumatic devices must be supplied with clean,
dry control air. Any other medium (e.g., oil
or moisture contamination) will result in the
device’s eventual failure.
3 psig 8 psig 13 psig
Thermostat Pressure
Max. Airflow
Min. Airflow
Reset Start Point (8 psig)
Reset Span (5 psig)
NOTE: Reset span is the pressure change at ‘T’
above the reset start point that causes the
ow setpoint to move from one extreme to
the other. In a direct reset application, the
ow setpoint will change from minimum
to maximum ow above the start point. In
a reverse reset application, the reset will
change from maximum to minimum ow
above the start point.
The CSC-3000 series are factory set with a reset span
of 5 psig. This is standard in most applications and
does not typically require adjustment. Leaving this
adjustment at the factory seing is recommended.
If necessary, the reset span can be adjusted (between
0 and 10 psig). If the reset span is changed, the
minimum and maximum ows may need to be
readjusted.
To adjust the reset span to another value, perform the
following steps:
1. Adjust the thermostat to a higher pressure,
beyond working range (20 psig is best).
2. Aach a pressure gauge to the “G” port (requires
5/32" O.D. tubing).
3. With a small at-blade screwdriver, adjust (coun-
terclockwise to increase; clockwise to decrease)
the reset span control (at the boom of the con-
troller) until pressure at the “G” port equals the
desired reset span pressure. Pressure read at this
port will always be between 0 and the active reset
span seing.

CSC-3000 Series Pneumatic VAV Reset Volume Controllers 7 Applications Guide
Pressure Independent Operation Principles
(These instructions do not apply to the CSC-3014 or the CSC-3501/3505.)
Dierential pressure is sensed via a ∆P pick-up
mounted ahead of the damper (VAV terminal inlet).
The ∆P pick-up is a dual pressure pick-up sensing
both high and low pressures. The high pressure is
connected to the “H” port and the low pressure is
connected to the “L” port. These two pressures are
compared across the diaphragm. (No air is trans-
ferred between the “H” and “L” port.) The dia-
phragm positions a reset lever relative to the pres-
sure dierence between the force of the LO STAT ∆P
spring and the position of the HI STAT ∆P seing.
Turning the LO STAT ∆P knob counterclockwise (to
increase) repositions the reset lever away from the
normally open nozzle and towards the normally
closed nozzle. LO STAT ∆P adjustments must be
done with the “T” port pressure being less than the
RESET START pressure.
“NO” DAMPER selection (normally open
dampers)—turning the LO STAT ∆P knob
counterclockwise (increase) will reposition the
reset lever away from the normally open nozzle,
decreasing the “B” port pressure and increasing
airow through the terminal unit.
“NC” DAMPER selection (normally closed
dampers)—turning the LO STAT ∆P knob
counterclockwise (increase) will reposition the
reset lever towards the normally closed nozzle,
increasing the “B” port pressure and increasing
the airow through the terminal unit.
Turning the HI STAT ∆P knob counterclockwise
(to increase) repositions the fulcrum towards the
nozzles. HI STAT ∆P adjustments must be done with
the “T“ port pressure being greater than the RESET
START pressure plus the RESET SPAN pressure.
•
•

CSC-3000 Series Pneumatic VAV Reset Volume Controllers 8 Applications Guide
Magnehelic Gauge to Airflow Rate Chart
VAV Airow Rate by Duct Size
30 50 100 150 200 300 400 600 1000 1500 2000 3000 4000 6000 8000
4 inch Round
5 inch Round
6 inch Round
8 inch Round 14 inch Oval
12 inch Round
10 inch Round 16 inch Oval
18 inch Oval
20 inch Oval
.02
.03
.04
.05
.06
.07
.08
.09
.10
.15
.20
.25
.30
.40
.50
.80
.70
.60
1.0
.90
CFM Flow Rate as read by sensor
Differential Pressure (∆P) in Inches w.c.
NOTE: This chart is for illustration only! Do not
use this chart to obtain your values. It
is NOT intended for calibration of your
Minimum and Maximum adjustments.
This airow chart is an example of the charts usually
axed to the VAV box. Each chart is specic for the
type of ow sensor located in the inlet side of the VAV
box. Read the dierential pressure of the Magnehelic
gauge, follow the line horizontally until it crosses the
diagonal inlet size of box. Read straight down from
this intersection to determine the ow rate.

CSC-3000 Series Pneumatic VAV Reset Volume Controllers 9 Applications Guide
Applications
DA Thermostat (NO or NC Damper)
RA Thermostat (NO or NC Damper)
Cooling
(These instructions do not apply to the
CSC-3014 or the CSC-3501/3505.)
LO STAT = Min. Flow
HI STAT = Max. Flow
Reset Range = 8 to 13 psig
•
•
•
LO STAT = Max. Flow
HI STAT = Min. Flow
Reset Range = 3 to 8 psig
•
•
•

CSC-3000 Series Pneumatic VAV Reset Volume Controllers 10 Applications Guide
Cooling with Heating Valve
DA Thermostat, NO or NC Damper, and NO Hot Water Valve
RA Thermostat, NO or NC Damper, and NC Hot Water Valve
LO STAT = Min. Flow
HI STAT = Max. Flow
Reset Range = 8 to 13 psig
•
•
•
Hot Water Valve = NO
Spring Range = 3 to 8 psig
•
•
LO STAT = Max. Flow
HI STAT = Min. Flow
Reset Range = 3 to 8 psig
•
•
•
Hot Water Valve = NC
Spring Range = 8 to 13 psig
•
•

CSC-3000 Series Pneumatic VAV Reset Volume Controllers 11 Applications Guide
Cooling with Heating P. E.
DA Thermostat, NO or NC Damper, and NC Heating PE Switch
LO STAT = Min. Flow
HI STAT = Max. Flow
Reset Range = 8 to 13 psig
•
•
•
NC PE
Switches
Stage 2 On with Decrease
Stage 3 Off with Increase
•
•
Stage 1 On with Decrease
Stage 2 Off with Increase
•
•
Stage 3 On with Decrease•
Stage 1 Off with Increase•
LO STAT = Max. Flow
HI STAT = Min. Flow
Reset Range = 3 to 8 psig
•
•
•
NO PE
Switches
RA Thermostat, NO or NC Damper, and NO Heating PE Switch
Stage 2 On with Decrease
Stage 3 Off with Increase
•
•
Stage 1 On with Decrease
Stage 2 Off with Increase
•
•
Stage 3 On with Decrease•
Stage 1 Off with Increase•

CSC-3000 Series Pneumatic VAV Reset Volume Controllers 12 Applications Guide
Dual Duct
Cold Deck CSC-3011-10
Damper = NC
LO STAT = Min. Flow
HI STAT = Max. Flow
Reset = 8 to 13 psi
•
•
•
•
Hot Deck CSC-3011-10
Damper = NO
LO STAT = Max. Flow
HI STAT = Min. Flow
Reset = 3 to 8 psi
•
•
•
•

CSC-3000 Series Pneumatic VAV Reset Volume Controllers 13 Applications Guide
© 2006 KMC Controls, Inc. AN-1205B-RevA
KMC Controls, Inc.
19476 Industrial Drive
New Paris, IN 46553
574.831.5250
www.kmccontrols.com
[email protected]
Dual Duct, Constant Volume
Cold Deck/Common Discharge CSC-3011-10
Damper = NC
LO STAT = Constant Volume Flow
Reset = 8 to 13 psi
•
•
•
Hot Deck CSC-3011-10
Damper = NO
LO STAT = Min. Flow
HI STAT = Max. Flow
Reset = 13 to 8 psi
•
•
•
•