lbertran said:It could be that there was antifreeze in the water heater from the last winterization of the fresh water system. If antifreeze is allowed to be heated, it can create an unpleasant smell.
Footloose, 1985 E35-3
Guy Stevens said:Does it smell sickley sweet? = Leak from the heat exchanger into the tank.
Metalic = Sediments
Old Socks? = Sulphor, bacterial breakdown of biological mass
Each has a different cause, and a different treatment, however that said, if it doesn't smell Sickley sweet, (Which means it is dead, and needs to be thrown out), then you should flush it. I would go ahead and flush it really welll.........
WITH THE HEATER OFF
At the dock, disconnect the input hose from the pump on your system, plumb a short hose onto it that you can stick in a bucket. Drain the water heater, using the drain plug.
First Fill the bucket up with vinegar, straight a good place to get cheap vinegar by the gallon is Costco. (This is an anti-scaling compound, known in the chemical world as acidic acid.). Pump this through your system into the water heater. Try to get the water heater full of the vinegar. Leave it sit for several hours.
Next put fresh water in the buckets and pump through the system till all the vinegar, and the associated brown crud comes out of the water heater. (Now sometimes your pump doesn't have enough umph to make this happen, and you have to get the shore power hose with better pressure connected into the game, but you have to be carefull not to burst any fittings or hoses when you are using the higher pressure.) Again drain it.
Next you can neutralize the water tank to eliminate the acids, drive it base, and get rid of any of the bacteria that may be acid dweling. To do this fill your bucket with water, and disolve a box of baking soda in it.... Pump this through, again trying to let the water heater stay full of the mixture for a couple of hours at a minimum.
Again pump clean water through it, then drain it.
Third do a bilogical shock, mix up about 2 capfulls of unscented Chlorox tm in each of your five gllon buckets and pump that into the water heater.... Again leave site for several hours if not overnight.....
Pump the water heater out again with clean water....... And again drain it.... Then hook everything back up.
If you still get the smells etc, it may be that your tanks need the same treatment, and that the smell is from the water in the tanks and is more prevelent to the nose in the heated water. (Cold spagatti sauce has no smell, only when you heat it in a pan do you smell it. )Drain the tnanks fill with vinegar based solution, drain, fill with baking soda, drain rinse fill with Chlorox. Drain rinse fill with fresh water taste smelll etc...