Part
1. Overview
18
Design Guide
DCM014A51
Figure 13. Cool/Heat Changeover Logic
Case 2: Changeover at the secondary changeover temperature.
1. By default, the secondary changeover temperature is 1°F above the primary changeover
temperature for cooling, or 1°F below the primary changeover temperature for heating,
which is configurable between 1°F – 4°F.
2. Case 2 will happen while the guard time is active in Case 1.
3. The
iTM
auto-changeover is applicable to both Heat Pump and Heat Recovery systems.
a. The
iTM
provides four changeover methods to meet a variety of expectations in a
project. Fixed, Individual, Average, or Vote methods can be specified in the
changeover group with targeted indoor units, as well as Primary/Secondary
Changeover deadbands.
1. Fixed Method:
a. Changeover is evaluated with the representative indoor unit.
b. Changeover affects all indoor units.
c. Good method for prioritizing the representative indoor unit for the Heat Pump
system (or multiple units on the same port of the BS Box in Heat Recovery
system).
Figure 14. Fixed Method