710 / 710 ASME Service manual
Ver. 1.00
8
CONFIDENTIAL
5. Schematic diagram
1.
When a hot water tap is opened, cold water enters the 710.
2.
The water flow sensor detects this water flow and sends this information to computer.
3.
The computer initiates fan motor and sends signal to igniter to create ignition spark.
4.
The main, proportional, and solenoid gas valves open to allow gas input.
5.
The gas ignites and flames appear inside the burner chamber.
6.
Water circulates through the heat exchanger and is heated up to the set temperature.
7.
Using thermistors to measure temperatures, the computer modulates the gas and water valves to
ensure proper output water temperatures.
8.
When the tap is closed, the 710 shuts down.
Output Thermistor
Gas proportional valve
Gas solenoid valve 2
Gas solenoid valve 1
Gas solenoid valve 3
Water control
valve
Mixing Thermistor
Igniter rod
Heat
Exchanger
Gas
Hi-limit switch
Flow sensor
Exhaust
O.H.C.F
Main gas valve
Burner
Igniter
Fan motor
Hot water
Cold water
Inlet
Thermistor
Air-fuel ratio rod
Flame rod
Surge box
P C B
G F I
A C 1 2 0 V
Transformer
120 VAC