Hydrogen gas build up in water tank?

[PleinAirCedar]

Hello Everyone,
I plan to use my hot water tank for the first time this year. I've had my 17B for 3 summers already and never needed to use it as I either boiled a little water for washing or used sinks at campgrounds to wash dishes and used the available showers in the bathrooms there, too.
I removed the anode and cleaned out the tank by just sticking the garden hose in there and flushing it out. This was last fall before I winterized the water system by using my compressor to blow it out. I put the anode back in sans Teflon tape but will clean it again once the danger of a hard freeze is past. I'll put the anode back in with Teflon tape, too.

I was reading the owners manual and came across this warning:
"HYDROGEN CAN BE PRODUCED IN THE WATER HEATER SYSTEM IF THE HEATER HAS NOT BEEN USED FOR A LONG TIME, GENERALLY TWO WEEKS OR MORE. THIS IS ESPECIALLY TRUE IF THE WATER HEATER HAS BEEN DRAINED. HYDROGEN GAS IS EXTREMELY FLAMMABLE. DUE TO THE RISK OF SERIOUS INJURY OR DEATH UNDER THESE CONDITIONS IT IS RECOMMENDED THAT THE HOT WATER FAUCET BE OPENED FOR SEVERAL MINUTES AT THE KITCHEN SINK BEFORE USING ANY ELECTRICAL APPLIANCES. IF HYDROGEN IS PRESENT THERE WILL PROBABLY BE AN UNUSUAL SOUND, LIKE AIR ESCAPING THROUGH THE PIPE AS THE WATER BEGINS TO FLOW. THERE SHOULD BE NO SMOKING OR OPEN FLAME NEAR THE WATER FAUCET WHEN IT IS OPENED."
Its on page 53 of the 2017 17B manual even though my 17B is a 2018.
Has anyone had a problem with hydrogen gas coming out of the water tank and hissing through the pipes? If you have, how did you solve/deal with the problem.
Thanks so much!

[cpaharley2008]

New warning to me, ignorance is bliss, but you are right, everyone should be informed....thanks. I thought after owing 3 prior Escapes, nothing changed!

[C&G in FL]

I’ve read that too. Never been a problem, but I am a non-smoker. However, you are going to either open the faucet or the pressure release valve before turning on the water heater so if there were any hydrogen in the tank, it would be displaced by water. IMO, offgassing by lead acid batteries during heavy charging or equalization is a more likely source of hydrogen. When I leave home for an extended Escape trip, I turn off the water heater. Though not empty, have never had a problem there, either.

[HABBERDABBER]

from: https://chemistry.stackexchange.com/questions/14121
/how-does-hydrogen-gas-build-up-in-hot-water-lines




Water reacts with the magnesium sacrificial anode over time to make H2. Normally, you'd be using your hot water often enough that you wouldn't notice the minute amounts of H2 coming out the tap with the hot water. But if your place is vacant for some time, a significant amount of H2
could build up and an ignitable mixture come out the first time a tap is turned on (or a dishwasher, which is a case study of an explosion occurring such that the appliance rocketed out from its mooring and hit the opposite kitchen wall).
Depending on the chemistry of your water, the reaction with the anode might be vigorous such that you could be getting puffs of hydrogen out of every use of the hot tap enough to set off "flammable gas" alarms. In this case or otherwise excessive consumption of your anode, switching to an aluminum anode may help.
In addition, bacteria can use the H2
as food and fart out H2S instead, giving the water a "rotten egg" odor instead. The aluminum anode switch can help with this too, or temporarily setting the heater to 160F for a day to kill the bugs (although exotic bacteria of this type can survive at high temp, and furthermore the H2S may be from the supply instead if the tank if the cold stinks too).
And yes, this has nothing to do with gas vs. electric heaters, it's purely the chemical reaction between water and the anode.
Summary: Run your hot tap for a few minutes after leaving your house vacant for some time; switch to an aluminum sacrificial anode.

[PleinAirCedar]

Originally Posted by HABBERDABBER

from: https://chemistry.stackexchange.com/questions/14121
/how-does-hydrogen-gas-build-up-in-hot-water-lines




Water reacts with the magnesium sacrificial anode over time to make H2. Normally, you'd be using your hot water often enough that you wouldn't notice the minute amounts of H2 coming out the tap with the hot water. But if your place is vacant for some time, a significant amount of H2
could build up and an ignitable mixture come out the first time a tap is turned on (or a dishwasher, which is a case study of an explosion occurring such that the appliance rocketed out from its mooring and hit the opposite kitchen wall).
Depending on the chemistry of your water, the reaction with the anode might be vigorous such that you could be getting puffs of hydrogen out of every use of the hot tap enough to set off "flammable gas" alarms. In this case or otherwise excessive consumption of your anode, switching to an aluminum anode may help.
In addition, bacteria can use the H2
as food and fart out H2S instead, giving the water a "rotten egg" odor instead. The aluminum anode switch can help with this too, or temporarily setting the heater to 160F for a day to kill the bugs (although exotic bacteria of this type can survive at high temp, and furthermore the H2S may be from the supply instead if the tank if the cold stinks too).
And yes, this has nothing to do with gas vs. electric heaters, it's purely the chemical reaction between water and the anode.
Summary: Run your hot tap for a few minutes after leaving your house vacant for some time; switch to an aluminum sacrificial anode.

I think if I flush out the hot water tank with the hose and then install the standard anode and sanitize with bleach (the whole system), I should be ok. I may just leave the anode out and put in a small circle of screen to keep spiders out of the water heater. Leave it for a week or so as we still could get a killer freeze here.



It seems that I feel this applies to keeping your water heater in functioning condition and in use. It doesn't seem to apply to an empty and sort of damp water heater tank.
thanks!

[TTMartin]

Originally Posted by PleinAirCedar

:I may just leave the anode out and put in a small circle of screen to keep spiders out of the water heater.

While not having the anode in for a couple weeks probably won't be a problem, don't do it over the winter. The threads can get corrosion on them making it hard to reinstall the anode.

[jerryc]

Now I know what apparenty caused this.

[C&G in FL]

Originally Posted by HABBERDABBER

from: https://chemistry.stackexchange.com/questions/14121
/how-does-hydrogen-gas-build-up-in-hot-water-lines




Water reacts with the magnesium sacrificial anode over time to make H2. Normally, you'd be using your hot water often enough that you wouldn't notice the minute amounts of H2 coming out the tap with the hot water. But if your place is vacant for some time, a significant amount of H2
could build up and an ignitable mixture come out the first time a tap is turned on (or a dishwasher, which is a case study of an explosion occurring such that the appliance rocketed out from its mooring and hit the opposite kitchen wall).
Depending on the chemistry of your water, the reaction with the anode might be vigorous such that you could be getting puffs of hydrogen out of every use of the hot tap enough to set off "flammable gas" alarms. In this case or otherwise excessive consumption of your anode, switching to an aluminum anode may help.
In addition, bacteria can use the H2
as food and fart out H2S instead, giving the water a "rotten egg" odor instead. The aluminum anode switch can help with this too, or temporarily setting the heater to 160F for a day to kill the bugs (although exotic bacteria of this type can survive at high temp, and furthermore the H2S may be from the supply instead if the tank if the cold stinks too).
And yes, this has nothing to do with gas vs. electric heaters, it's purely the chemical reaction between water and the anode.
Summary: Run your hot tap for a few minutes after leaving your house vacant for some time; switch to an aluminum sacrificial anode.

All true. But aluminum is not as reactive as magnesium and if the intent is to sacrifice the anode rather than the tank, magnesium anodes provide better sacrificial protection. With either material, there are benefits and drawbacks. I, personally, would rather replace a water heater at a shorter time interval rather than smelling hydrogen sulfide constantly and would gladly switch to an aluminum in that situation.