Schematic Diagram - A.O. Smith 240 T-H3J Service Manual

5. Schematic diagram

Direct Vent Indoor models only
Hi-limit switch for exhaust
Intake port
Exhaust thermistor
Drain pan
Hi-limit switch
540 (T-H3) models only
Heat exchanger thermistor
Bypass valve
Flow adjustment valve
with Flow sensor
ON-OFF-switch for power supply
Outlet thermistor
Inlet thermistor
1. When a hot water tap is opened, cold water enters the water heater.
4. The main, proportional, and solenoid gas valves open to allow gas input.
ensure proper output water temperatures.
8. When the tap is closed, the water heater shuts down.
NOTICE
240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial
PCB
Heater
Drain plug
Inlet drain
13
Exhaust
Secondary heat exchanger
Primary heat exchanger
O.H.C.F
Flame rod
Igniter rod
Igniter
Gas solenoid valve 1
Main gas valve
120
Condensate drain
VAC
Gas solenoid valve 2
Gas solenoid valve 3
Surge box
Page
CONFIDENTIAL
Ver. 1.00