Valve And Damper Selection - Honeywell AUTOMATIC CONTROL Engineering Manual

VALVE AND DAMPER SELECTION

Pneumatic valve and damper actuators are shown in these
examples. If actuators are electric, certain ones need not
be spring return unless a specific reason exists. Table 1
Actuator Application
Dampers
Outdoor air
Relief air (to outdoor)
Return air
VAV fan inlet vanes
VAV box
Multizone hot deck, cold areas
Multizone hot deck, hot areas
Valves
AHU chilled water
Terminal reheat
Preheat in OA below 35F
Preheat in OA above 35F
Other hot water
AHU steam heating
Steam humidifier
1
Return air dampers need no springs if the associated fan is delayed upon start-up to allow the RA damper to properly
position to assure that the fan does not start with both RA and OA dampers closed.
2
If a duct temperature sensor is located near a hot water or steam coil, leaving the coil under control (with a setpoint of
80°F to 100°F) during equipment shutdown can provide added freeze alarm protection. If variable flow hot water
pumping is provided and a duct low temperature control senses freezing conditions, hot water valves may be
positioned approximately 25% open if a temperature sensor is not available.
Table 1. Valve and Damper Actuator Selection Guide.
Pneumatic Actuators
System
Shutdown
Closes
Opens
Closes
Owner Perference
Opens
Closes
Closes
2
Opens
Closes
2
Closes
Closes
207
AIR HANDLING SYSTEM CONTROL APPLICATIONS
outlines general actuator selection. The table indicates
actuator positioning desired on system shutdown and loss
of motive force.
System
Loss of Air Shutdown
Closes Closes
Opens Opens
Closes Closes
Opens Owner Perference
Opens
Closes Closes
Opens Closes
Opens
Closes
Closes
Closes
Closes
ENGINEERING CMANUAL OF AUTOMATION CONTROL
Electric Actuators
Loss of
Electricity
Closes
1
Opens
Closes
Owner Perference
Opens
Closes
Stays same
2
Opens
2
Stays same
Closes