T.a.c. 2212-318 General Instructions Manual
Printed in U.S.A.
8/08
©
Copyright 2008 TAC All Rights Reserved.
F-24576-4
Application
The 2212-318 and 2212-319 Dual Setpoint/Deadband
Pneumatic Room Thermostats are designed for the
proportional control of pneumatic valves, damper
actuators, or other final control devices in
environmental control systems. These devices are
used when it is desirable to set up, between selected
heating and cooling setpoints, a temperature span
within which the HVAC system uses no energy for
heating or cooling. The high capacity, two-pipe,
pilot-operated, relay-type design provides pneumatic
feedback for accuracy and stability over the entire
operating range.
These thermostats are available in either direct- or
reverse-acting models, each utilizing two bimetals, one
heating and one cooling, to interrupt the deadband
(branch) pressure. In the direct-acting model, the
heating bimetal modulates the pressure between zero
and the deadband pressure, and the cooling bimetal
modulates the branch pressure between the deadband
pressure and main air pressure. In the reverse-acting
model, this action is reversed. The deadband pressure
is adjustable in the field, to adapt to specific
applications. Two concealed setpoint dials, one
heating and one cooling, are used to set the individual
heating and cooling setpoints to the desired values.
This creates the desired deadband between the two
selected setpoints. All calibration functions are
accessible from the front of the thermostat. The use of
a blank cover (21-928) is recommended with this
device. Other cover options may be utilized if desired.
Features
•
Factory-calibrated, stainless steel ball-in-seat
provides pneumatic feedback for stable, linear
operation.
•
Deadband is easily selected by setting the desired
heating and cooling setpoints.
•
Field-adjustable deadband output pressure is
factory set at 8 psig.
•
Leak-proof, self-closing branch gauge tap.
SPECIFICATIONS
Action: Proportional.
Setpoint Range:
Heating, 57 to 75
°
F (14 to 24
°
C).
Cooling, 65 to 83
°
F (18 to 28
°
C).
Throttling Range: 1.5
°
F (approx.) non-adjustable for each
setpoint.
Maximum Air Pressure: 30 psig.
Main Air Consumption: 30 scim.
Setpoint Adjustment: Individual concealed adjustments for
heating and cooling by means of a 20-881 calibration wrench.
Calibration:
Deadband, Factory-set at 8 psig (adjustable).
Direct-Acting Models,
Heating 5.5 psig at setpoint.
Cooling 10.5 psig at setpoint.
Reverse-Acting Models,
Cooling 5.5 psig at setpoint.
Heating 10.5 psig at setpoint.
Construction:
Mechanical Components, Die cast aluminum, stainless
steel, and glass-filled nylon.
Diaphragm, Fabric-reinforced Neoprene.
Air Lines, Connect to thermostat nipples with
spring-reinforced plastic tubes.
Branch Connections, Equipped with internal fiters.
Environment
Humidity: 5 to 95% relative humidity, non-condensing.
Locations: NEMA Type 1.
2212-318
2212-319
Dual Setpoint/Deadband
Pneumatic Room Thermostats
General Instructions
Blank Cover Shown
(Covers must be ordered
separately except as noted.)