Titus TA1 Installation Manual

TA1/TA2 Controller, CTE-5202 Thermostat
Installation, Operation, and Maintenance Manual

General Information

Power Requirements

TITUS TA1/TA2 controllers operate on 24 VAC power. Power
required to operate the controller and actuator is 7 VA plus any output
loads for fan relays, heating contactors, and control valves (assume
10 VA each). Always switch control voltage off prior to disconnecting
any wires from the controller to prevent possible damage to control
components.

Damper Control

TITUS TA1/TA2 controllers provide pressure independent VAV control
for terminal primary air valves. Primary airflow volume is monitored by
means of a multipoint center-averaging velocity sensor located in the
inlet duct. Differential pressure is measured by an on-board platinum
ceramic transducer. Dampers are always shipped full open and move
counter-clockwise (CCW) to close. The primary damper opens and
closes to vary air volume to match cooling demand. Changes in static
pressure will result in damper position changes for a given flow
volume. In automatic changeover (ACO) sequences, the primary
damper also moves to match heating demand. If the primary fan
system is off and the terminal is calibrated to control a minimum flow
limit other than 0 cfm, the damper will drive full open. Flow limit
adjustments are at the thermostat (As shown in Figure 1).

Live Supply Volume Readout

A voltage output corresponding to actual primary air volume may be
monitored at the thermostat to assist in balancing and troubleshooting
these units. This output signal follows the same cfm vs DC voltage
calibration curve that is shown on Figures 4 and 5.

Supply Air Temperature Sensing

A duct-mounted thermistor is used to measure primary air
temperature in sequences involving automatic changeover (ACO) or
morning warm-up (MWU). It is fastened to the inlet duct with a
sheetmetal screw and wired to terminals 'AI1' and '┴' on the
thermostat (As shown in Figure 2).
Alternatively, autochangeover and morning warm-up may be triggered
by a contact closure. When controller terminals 'X' and 'Y' are shorted
together, the unit will operate in the heating or morning warm-up
mode. When there is an open circuit between 'X' and 'Y', the unit will
operate in the cooling mode.

Night Setback/Unoccupied Signal

Units ordered with optional night setback (NSB) sequences employ a
differential pressure switch (As shown in Figure 3) to sense loss of
primary duct static pressure. By this method, these units change
operating mode when the air handler fan is de-energized.
Alternatively, night setback operation may be triggered by a 24 VAC
signal (10 mA) from a source external to the unit. Whenever 24 VAC
is applied to controller terminals '-NSB' and 'NSB', unit will operate in
night setback mode.
Installation Manual
Figure 1.
Figure 2.
Figure 3.
ANA-IOM-1.0 3-10-20
Pressure Switch