degrees C 4 to 15 degrees F. Room thermostat shall have concealed setpoint
dial [, covers with Allen screws] [, aspirator type wall box with flush
plate and locking screws] [, built-in concealed thermometers] [, exposed
adjustment covers with visible thermometers for family housing], and
plug-in gage ports.
2.8.8
Modulating, Insertion, Immersion, & Averaging Pneumatic Thermostats
**************************************************************************
NOTE: Indicate remote bulb return air thermostats
in lieu of room thermostats where acceptable.
**************************************************************************
Thermostats shall be two-pipe, pilot-operated type with pneumatic feedback,
proportional action and shall have an adjustable throttling range of one to
55 degrees C 2 to 100 degrees F with a minimum range of minus 12 to plus
121 degrees C 10 to 250 degrees F. Averaging elements shall be 825 mm 1
foot in length for each square meter 4 square feet of ductwork
cross-sectional area with a minimum length of 2.44 meters 8 feet.
2.8.9
Nonmodulating Pneumatic Thermostats
Thermostats shall have integral positive acting relays, zero or maximum
output pressure. Remote element thermostats shall have standard or
averaging bulbs. Averaging bulbs shall be 825 mm one foot in length for
each square meter 4 square feet of ductwork cross-sectional area and a
minimum length of 2.44 meters 8 feet. Differential ranges shall be field
adjustable. Remote element thermostat differential range shall be one to
14 degrees C 2 to 25 degrees F with minimum control ranges of minus 23 to
plus 121 degrees C minus 10 to plus 250 degrees F. Room thermostat
differential range shall be one to 5.50 degrees C 2 to 10 degrees F with
minimum control ranges of 13 to 32 degrees C 55 to 90 degrees F.
2.9
SUNSHIELDS
Provide sunshields for outside air temperature sensing elements to prevent
the sun from directly striking temperature sensing elements. Provide
sunshields with adequate ventilation so that the sensing element responds
to the ambient temperature of surroundings. The top of each sunshield
shall have galvanized metal or aluminum rainshield projecting over the face
of the sunshield. Sunshields shall be painted white or shall be unpainted
aluminum.
2.10
PRESSURE SWITCHES AND SOLENOID VALVES
Provide pressure switches and solenoid valves.
2.10.1
Pressure Switches
Switches shall have an adjustable setpoint with visible setpoint scale.
Range shall be as indicated. Differential adjustment shall span 20 to 40
percent of the range of the device.
2.10.2
Differential Pressure Switches
Switches shall be an adjustable diaphragm-operated device with [two SPDT]
[one SPDT] contacts, with taps for sensing lines to be connected to duct
pressure fittings designed to sense air pressure. Fittings shall be
angled-tip type with tips pointing into the airstream. [Range shall be 125
SECTION 15901N
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