Rinnai I Series Installation And Operation Manual page 97

Hot Water Supply
Building Outlets
When the recirculation logic starts, the pump will operate as described below:
•
When the DHW return water temperature reaches approximately 6°F (3°C) below the
DHW set point temperature, power to the pump will be discontinued from the PC Board.
•
After the off interval time of the boiler has passed, the pump will turn on again.
•
If the boiler does not detect flow from the pump during the DHW recirculation on times,
an E631 diagnostic code will display on the controller.
IMPORTANT
The target flow rate for DHW recirculation is from 1.3 GPM (5 L/min) to 4 GPM (15 L/min). If the
flow rate is less than 0.8 GPM (3 L/min), the DHW recirculation pump will operate and an E631
diagnostic code will display on the controller. If the DHW recirculation pump flow rate drops to
less than 0.4 GPM (1.5 L/min), the DHW recirculation pump will stop and an E631 diagnostic
code will display on the controller. The proper pump size needs to be selected for the pressure
drop through the recirculation loop (maximum current: 2 Amps).
Rinnai I-Series Condensing Boiler Combi Manual
DHW Recirculation Pump
Timer
DHW Recirculation Pump
Connect to "DHW_Pump
Terminal" (label on PC Board)
Timer Connects to T/T 2
Gas Supply
Cold Water Supply Line
Building Return Line
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