Opening the relief valve when filling CAN (not always) get rid of the air pocket that is engineered into the design of WH Tank. Air pocket allows for pressure increases due to swelling of water when heated. Loss of air pocket----weeping relief valve.
To not lose air pocket......turn on water supply and bleed air via hot/cold faucet (Cold inlet valve open/hot outlet open---if you have one/bypass closed)
Also not ALL WHs have 2 switches for electric element
Suburban has an ON/OFF switch in outside compartment----lower left corner. May have another on/off switch inside rv if mfg. adds one.
Atwood if 2003 or prior years will have an ON/OFF switch on backside of WH Tank on cover over electric element. May have another inside rv if mfg. adds one.
2004 and newer ones will only have an ON/OFF switch on panel on wall.
