Component Replacement Instructions
Ignition line
Six screws
Wire harness connector
PC Board (dip switches)
Three screws
1. Turn off the gas supply.
2. Turn off the 120 V power supply.
3. Remove four screws securing the front panel. Remove front panel.
4. Pull out wire harness connector at the gas manifold assembly. See Figure 1.
5. Move aside the ignition line by pulling it out from the clear plastic tubing.
6. Remove the six screws that attach the gas manifold to the combustion chamber (part of the heat
exchanger assembly).
7. Remove the three screws
that attach the gas manifold to the gas valve. Pull out the gas manifold.
Figure 1
8. Remove the four screws attaching the gas connection to the underneath side of the water heater.
See Figure 2.
Figure 2
Gas connection attached with 4 screws
Regulator screw access
9. Pull the gas connection down to disconnect it from the gas control assembly.
10. Pull out the gas control assembly. Remove the wire harness from the 4 solenoids.
11. Replace the O-ring (included in kit) where the assembly attaches to the gas connection. Make sure
the old O-ring is removed and discarded. Install the new gas control assembly.
WARNING
Failure to correctly assemble the components according to these instructions
could result in a gas leak or explosion.
305e/o, 305i, 505e/o, 505i
On-Demand Gas Tankless Water Heater Service Manual
20
Gas Control Assembly
