72 Appendixes
6.7 Navien H
2
Air Add-on Controller Kit (Optional)
The Navien H2Air is an add-on controller for the water heater. It adds input and
output functions to the water heater for a combination application where space
heating and domestic hot water (DHW) are supplied simultaneously. With this add-
on controller, a thermostat (1 or 2-stage) and an outdoor sensor can be installed
along with a hydronic air handler to add space heating functionality to the system.
6.7.1 Basic Principles
The following diagram shows the basic operation of the heater system with the Navien H2Air add-on controller.
CAUTION
Do not configure the system for DHW recirculation when it is configured to run an air handler using the
H2Air add-on controller. DHW recirculation and Navien H2Air configurations cannot be used at the same
time.
Flow Switch
Check
Valve
Cold Water
Supply
DHW Supply
Space Heating
Supply
Heat Demand
Output
Thermostat
Outdoor Sensor
Water Heater
Space Heating
Return
Mixing
Valve
Expansion
Tank
For details, refer to the installation manual that is provided with the H2Air add-on controller kit.
