Space Temperature Control; Single Loop Space Temperature Control; Single Zone Variable Air Volume - Trane Symbio 700 Controller Application Manual

Space Temperature Control

System Types of VVZT and CVZT operate to provide space comfort heating and cooling. A system
mode wired input or Heat Cool Mode Request input determines the heating or cooling mode of
operation. If a heat cool system mode input is not provided, the Symbio™ 700 operates per Heat Cool
Mode Request default value, Auto is the default setting. In Auto, the controller will automatically
determine it is appropriate to heat or cool based on space temperature, setpoints, and heating/cooling
configured for the unit. The space temperature and space temperature setpoints determine a space
heating or cooling demand. If space temperature is above the cooling setpoint, this represents a space
cooling demand.
Symbio 700 supports two types of space temperature control: Single Loop Space Temperature Control
and Single Zone Variable Air Volume.

Single Loop Space Temperature Control

Configured VVZT and CVZT System Types operate in Single Loop Space Temperature Control when
only a space temperature input is provided the Symbio™ 700 control (no discharge air temperature
sensor installed). In heating modes, with staged gas heat or staged electric heat installed, the supply fan
will operate at maximum speed. In cooling modes, the supply fan will operate at the lowest speed
allowed for the stage of cooling capacity and 100% when all compressor stages are on. When space
temperature is between the heating and cooling setpoint, the supply fan operates at a minimum speed.
Alternately, the supply fan can be setup to cycle off when there is no demand for heating or cooling via
Supply Fan Configuration Command setting.
Cooling capacity increases as space temperature increases above the cooling setpoint. Heat capacity
increases when space temperature decrease below the heating setpoint. Capacity decreases has
space temperature approaches the desired space setpoint.
Figure 6. Multi-speed fan sequence of operation

Single Zone Variable Air Volume

Single Zone VAV operates in DX and economizer cooling modes of operation when configured for
System Type: VVZT (variable speed indoor fan type) or CVZT (multi speed indoor fan type). A valid
16 ACC-APG002A-EN