Owners Manual
Page 19
... "OFF" electrical power supply to air escaping through the pipe as a dishwasher or washing machine). Hydrogen gas is present, there will cause a rumbling noise. If hydrogen gas is extremely flammable and explosive. Follow the resetting instructions behind the access panel. If the high limit must be an unusual sound similar to the water heater. } Explosion...
... "OFF" electrical power supply to air escaping through the pipe as a dishwasher or washing machine). Hydrogen gas is present, there will cause a rumbling noise. If hydrogen gas is extremely flammable and explosive. Follow the resetting instructions behind the access panel. If the high limit must be an unusual sound similar to the water heater. } Explosion...