Operating Principle - Noritz NR50-OD Service Manual

5. Operating Principle

NR50-OD
NR66 (-SV,-OD) / N-0531S (-OD),
NR71 (-SV,-OD) / N-0631S (-OD)
Circuit Board
G.F.C.I.
Transformer
AC120V
Gas Solenoid
Igniter
Valve 2
Gas Solenoid
Valve 1
Primary Gas Valve
Gas Supply
Frost Sensing Switch
(NR71-SV/N-0631S only)
Heat Exchanger
Thermal Fuse
Gas
Proportioning
Valve
Air Supply
Frost Sensing
Switch (Optional for NR50-OD)
Inlet
Thermistor
Water Flow
Sensor
Impeller
Water
Drain Valve
Cold Water Supply
NR66-SV/N-0531S,
Exhaust NR71-SV/N-0631S
NR66-OD/N-0531S-OD,
NR71-OD/N-0631S-OD
NR50-OD
Fan Motor
Rotational
Frequency
Sensor
Outlet
Thermistor
Water Filter
Water
Drain Valve
Hot Water
Fixture
34
Exhaust
High-Limit Switch
Flame Rod
Ignition Electrode
Burner
Flow Control Valve
Anti-Frost Heater
(Optional for NR50-OD)
Hot Water Supply