Installation Manual

H-Series Demand Duo™ 2 Installation and Operation Manual 38
The digital controller maintains communication between the tank and tankless via the tankless
communication cable to effectively control the tank temperature based on the selected temperature on
the tankless unit.
The digital controller will energize (120V) the pump when the tank temperature drops. When the tank
temperature returns to the selected set temperature, the digital controller will de-energize the pump and
remain in standby until the tank temperature drops again.
When power is supplied, the digital controller will maintain pump
operation. If system is not in use for an extended period of time,
disconnect power from the system.
ATTENTION
Controller Diagnostics
Tank Recovery Pump
Activated
Tankless Flow Rate has
dropped below 2.5 GPM
Slow flash indicates con-
troller is active with no
errors
Power supply is
working correctly
Displays Set
Temperature