Pc Board; 305E/O, 305I, 505E, 505I - A.O. Smith GTS-305-NE Service Manual

Component Replacement Instructions

PC Board

1. Turn off the gas supply.
2. Turn off the 120 V power supply.
3. Turn off the water supply.
4. Remove four screws securing the front panel.
Remove front panel.
5. Remove the plastic guard covering the front of the
PC board.
6. Remove the controller connections.
7. If a surge protector with terminals is installed, then
remove this board by removing two screws. This
board should be re-installed on the replacement PC
board.
8. Remove the two screws at the top and bottom of the
PC board.
9. Pull out the PC board, remove plastic cover, and
remove the connections.
10. Adjust dip switches on the new PC board.
Switches 1-8 (SW1): Configure the dip switches the
same as on the original PC board. If necessary,
refer to the Dip Switch section or to the Operation
and Installation Manual for more information on
these dip switches.
Switches 1-6 (SW2): Replacement PC boards have
an additional bank of 6 dip switches. Configure
according to the diagrams on the following page
based on your model and gas type.
11. Attach connections and plastic cover.
12. Insert PC board and attach with two screws.
13. If a surge protector with terminals was installed on
the original PC board, remove it and install it on the
new PC board. See Figure 15.
14. Attach connections for the remote controller.
15. Attach plastic guard.
16. Perform the Gas Pressure Setting Procedure.
On-Demand Gas Tankless Water Heater Service Manuals
305e/o, 305i, 505e/o, 505i
27
Figure 15
Screw
Remote controller
terminals
(NOT for 120 V power)
If these 2 terminals are
present then this is a
surge protector board
with terminals to
connect freeze
protection solenoid
valves and should be
installed with the new
PC board.
Attached with 2 screws
Screw