Sequence Of Operation - Rinnai N Series Manual

Sequence of operation

Incoming
Air
Igniter
FR
Heat
Exchanger
Thermistor
Water Flow
Control
Valve
Out going
Temperature
Thermistor
© 2015 Rinnai America Corporation
PROPRIETARY and CONFIDENTIAL
1. Water flow begins:
Exhaust
2. Ignition Sequence:
Combustio
n
Fan
3. Normal Operation:
Primary Heat Exchanger
Zero Governor
Gas Valve
Secondary Heat Exchanger
Bypass
Control
Valve
Water Flow
Sensor
4. Shut-down Sequence:
Gas
Supply
Connection
Enhancing Lives By Changing The Way Water Is Heated
5. Standby Mode:
- Water flow sensor sends pulses to the PCB.
- When flow exceeds approximately 0.4 gpm the ignition sequence begins.
- Combustion fan starts, drawing air in from the venting and through the unit.
- Spark igniter begins sparking.
- Gas control assembly opens. Gas is pre-mixed with air in the fan assembly then delivered
to the burner.
- Ignition Occurs.
- When the flame rod has proven flame the spark igniter stops sparking.
- PCB monitors flame rod, fan motor frequency, outlet water temperature, temperature set
point, and water flow rate.
- Fan speed modulates as needed to meet user's water flow demand.
- Zero Governor gas valve automatically maintains proper gas/air mixture.
- Water is preheated in the secondary (latent) heat exchanger.
- Water is heated further as it passes through the primary heat exchanger.
- In certain circumstances the heat exchanger will purposely overheat the water inside the
heat exchanger while the bypass valve tempers the water down to the set point
temperature. This can provide for higher flow rates.
- The water flow control valve will limit flow as needed to maintain output temperature.
- Due to the combustion efficiency, condensation forms inside secondary heat exchanger
and drains into the condensate trap and through drain at the bottom of the unit.
- PCB senses flow rate less than 0.26 gpm.
- Gas control valve closes & water flow control valve resets to a standby position.
- Combustion fan will then run for a period of time to purge the combustion chamber.
- PCB monitors all components
3 8/17/2021