75
Installing a Cascade System
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System Application #5- Cascade System with DHW Indirect Tank (for Low DHW Demand)
Sub2
Sub1
Main
Temperature
sensors (required)
Cold water
Cold water
DHW
Supply
Return
Backflow
preventer
Indirect
tank
Aquastat
Air separator
12” (30 cm)
maximum
Expansion tank
Note
●
In this configuration, space heating and DHW can operate simultaneously.
●
The aquastat on the DHW indirect tank must be connected to a sub unit.
●
If a dedicated sub unit is used, the input capacity requirement of the indirect tank shall not exceed
the capacity of the single boiler.
●
Connect the DHW pump to the sub unit.
●
Connect zone pumps to the zone controller. Do not connect zone pumps to the main or sub units.
●
System Application 6 - Cascade System with DHW Indirect Tank (for Low DHW Demand)
Temperature
sensors (required)
Sub2
Sub1
Main
Cold water
Cold water
DHW
Supply
Return
Hydro/Air separator
Dirt collector
Backflow preventer
Expansion tank
Indirect
tank
Aquastat
Note
●
In this configuration, space heating and DHW can operate simultaneously.
●
The aquastat on the DHW indirect tank must be connected to a sub unit.
●
If a dedicated sub unit is used, the input capacity requirement of the indirect tank shall not exceed
the capacity of the single boiler.
●
Connect the DHW pump to the sub unit.
●
Connect zone pumps to the zone controller. Do not connect zone pumps to the main or sub units.