Trane Tracer VV550 Installation, Operation And Maintenance Manual page 46

Sequence of Operations
Hydronic heat is enabled if there is no valid primary air temperature. Hydronic heat is
disabled if the primary air temperature is greater than the configured reheat enable
setpoint.
Figure 1
Figure 1. Primary air temperature status determination
Air temperature
Hot
Cold
Note: For hydronic heat, set the configured reheat enable
setpoint to a very high value so that it does not affect
hydronic heat operation
For hydronic heat, the reheat enable setpoint is able to be configured. The hydronic heat
range is 70°F to 200°F (21.11°C to 93.33°C). When the primary air temperature is greater
than the configured reheat enable setpoint, reheat is turned OFF until the primary air
temperature drops 5°F (2.78°C) below the configured reheat enable setpoint. When no
primary air temperature is available, the controller checks the configured default primary
air temperature to determine if reheat can operate.
On/Off hydronic heat
The controller supports up to three stages of ON/OFF hydronic heat with no fan and two
stages with a fan (series or parallel). For more information on actuation, refer to
"Appendix D: Reheat Actuation Schedule Tables" on page
46
shows the primary air temperature status determination.
Primary air temperature
Hot
Warm
Primary air temperature
hysteresis region. No
change in primary air
temperature status.
Cold
Configurable points
Configured reheat enable
setpoint
Configured auto changeover
setpoint
Configured auto changeover
setpoint minus 10°F
97.
CNT-SVX17G-EN