5. Schematic diagram
The diagram below refers to both the T-D2-IN and T-D2-OS.
1. When a hot water tap is opened, cold water enters the T-D2-IN or T-D2-OS.
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 T-D2-IN or T-D2-OS shuts down.
H
O
T
C
O
L
D
G
A
S
PCB
Hi-limit SW
Inlet drain
plug filter
Mixing
Thermistor
Drain plug
Main gas valve
Gas solenoid valve 2
Fan motor
Flame rod
Igniter rod
Igniter
O.H.C.F
Heater
Flow adjustment valve
with Flow sensor
Gas proportional valve
Gas solenoid valve 1
Air-fuel ratio rod
Gas solenoid valve 3
Output
Thermistor
Bypass valve
Inlet
Thermistor
Transformer
To Next Page