8
Single-Duct and Retrofit Terminal Units IOM
PNEUMATIC CONTROLS
Volume controllers for LMHS units are shown below. Identification for each controller is shown in the following table.
PNEUMATIC VOLUME CONTROLLERS
KMC - CSC 2003
(Normally Open)
KMC - CSC 2004 (Normally Closed)
*LO and HI are reversed*
KMC - CSC 3011 (Multi Function Controller)
Figure 7: Pneumatic Volume Controllers
TABLE 2: PNEUMATIC CONTROL SEQUENCE CONTROLLERS
CONTROL SEQUENCE
FUNCTION ARRANGEMENT
KMC PART NUMBER
1102
DA-NO
CSC-2003
1103
RA-NC
CSC-2004
1104
DA-NO
CSC-3011
1105
DA-NC
CSC-3011
1106
RA-NO
CSC-3011
1107
RA-NC
CSC-3011
1108
DA-NO, DUAL MAXIMUM
CSC-3011
1109
DA-NO, HEATING/COOLING MAXIMUM
CSC-3011 (2X)
1110
DA-NO, DUAL MINIMUM
CSC-3011
1111
RA-NO, DUAL MINIMUM
CSC-3011
1112
RA-NO, HEATING/COOLING MAXIMUM
CSC-3011 (2X)
LEGEND: DA - DIRECT ACTING, NC - NORMALLY CLOSED, NO - NORMALLY OPEN, RA - REVERSE ACTING
PREPARATION FOR BALANCING
(CONTROL SEQUENCES 1102 AND 1103)
1. Inspect all pneumatic connections to assure tight fit and
proper location.
2. Verify that the thermostat being used is compatible with
the control sequence provided (direct acting or reverse
acting).
3. Check main air pressure at the controller(s). The main air
pressure must be between 15 psi and 25 psi. (If dual or
switched-main air pressure is used, check the pressure
at both high and low settings.) The difference between
high pressure main and low pressure main should be at
least 4 psi, unless otherwise noted, and the low setting
difference should exceed 15 psi.
4. Check that the unit damper will fail to the proper position
when main air pressure is lost. Disconnect the pneumatic
actuator line from the velocity controller and observe the
VAV damper position. The damper should fail to either a
normally open position (indicator mark on shaft end is
horizontal) or a normally closed position (indicator mark
on shaft end is vertical).
5. Check that there is primary airflow in the inlet duct.
6. Connect a Magnehelic gage, inclined manometer or other
differential pressure measuring device to the balancing
taps provided in the velocity probe sensor lines. The
manometer should have a full scale reading of 0.0 to
1.0 in. wg. The high-pressure signal is delivered from