8.2 Cascade System - Recirculation System Application Example
When using the cascade system, external recirculation can only be connected to and controlled by the NPE "A2"
water heater. Set each individual water heater to the appropriate recirculation mode utilizing the 2-way valve and
front panel settings. Refer to the NPE-A2 Installation Manual for additional details.
If Recirculation Return Line Is Installed
Connect the domestic hot water return line to the desired number of NPE "A2" water heaters. Set each
unconnected NPE "A2" water heater to Internal Recirculation Mode. The NCB-H boiler should be set to Combi
Pre-heat Mode.
Pressure
Relief Valve
Heating
Supply
Pump
Air Separator with
Expansion Tank
Optional Universal
Temperature Sensors
Heating Return
Note
The HotButton or Aquastat modes cannot be used in cascade systems.
78
Installing a Cascade System
Pressure
Relief Valve
Hydronic
Feed
Expansion
Water
Tank
NaviClean
(recommended)
<NPE-A2>
<NPE-A2>
Sub1
Sub2
<NPE-S2>
Sub3
Ball Valve
Domestic
Cold Water
Supply
Check
Valve
Faucet