I don't know why this just came to mind during camping season but when winterizing, I've always drained the hot water tank, flushed it out and put it on bypass before putting anti-freeze in my system. So the tank remains empty while in storage. So what prevents the inside of the tank from rusting when there's no water in the tank? There has to be periods of time where humidity and condensation form in the winter months meaning there's droplets of water that form on the tank walls. I always put the Anode rod back in rather than leaving an open hole but does the Anode rod still attract ions when surrounded by air rather than water?

Good question but I believe the tank is coated or plated internally. I do power rinse mine every spring. The anode rod flakes off and falls to the bottom.

Is leaving the rod out for long periods a mistake? Maybe an outwears material on the hole to allow air circulation but no critters?

I don't know what the proper way to do things is as far as whether to leave the anode rod in or out during the winter but I've always put it back in after flushing so I don't forget where I put it.

Suburban water heaters use a porcelain-lined, steel tank.Richard

I guess I'm confused then. Porcelain doesn't rust so what's the point of an anode rod if the tank is lined with porcelain? Is it in case the Porcelain breaks or the tank is somehow otherwise compromised?

Hot Water Tanks with Anode Rods | Good Sam Community

16 Replies

mobeewan
Explorer
Jun 17, 2019
The anode rod protects the tank and fittings at their threaded connections with the tank. These connections may have dissimilar metal fittings screwed into them. Including bronze relief valve, cast metal housing for temperature control valve that screws into the tank that also includes a copper temperature probe, cold water inlet fitting & brass check valve in the hot water outlet.
RobWNY
Explorer
Jun 17, 2019
Yes Soundguy, you're right. I used to have an Atwood HW tank on a previous TT I had. No Anode rod. Just a plastic plug for flushing thing out but I had no idea Suburban tanks were porcelain lined until today.
SoundGuy
Explorer
Jun 17, 2019
RobWNY wrote:
I learned quite a bit today about hot water tanks. I never knew they were porcelain lined for one thing.

Only Suburban WH tanks, Atwood tanks are aluminum and are not porcelain lined.
SoundGuy
Explorer
Jun 17, 2019
lryrob9301 wrote:
Sorry the previous poster was incorrect. Suburban tanks are aluminum, so the need for an anode rod and why they don't rust. Atwood tanks are glass lined thus no need for an anode rod.

Time to study up - it's exactly the reverse of what you're saying. :S
RobWNY
Explorer
Jun 17, 2019
Thanks everyone for your thoughts. I learned quite a bit today about hot water tanks. I never knew they were porcelain lined for one thing. I never allow anti-freeze to get in my hot water tank so that's never an issue and I do flush it out if it's going to to sit for weeks. I'll just keep doing what I have been doing. Flush/Put Anode Rod back in/By Pass/Winterize. I really need to think about summer things in the summer LOL
BB_TX
Nomad
Jun 17, 2019
lryrob9301 wrote:
Sorry the previous poster was incorrect. Suburban tanks are aluminum, so the need for an anode rod and why they don't rust. Atwood tanks are glass lined thus no need for an anode rod.

Sorry but you are wrong. Do your research.

Water Heaters by Atwood features Aluminum clad tanks while eliminating the need for an anode rod.

Heated water attacks all metals - and that's why Suburban uses a porcelain-lined, steel tanks with an anode rod to "absorb" the electrolytic action
lryrob9301
Explorer
Jun 16, 2019
Sorry the previous poster was incorrect. Suburban tanks are aluminum, so the need for an anode rod and why they don't rust. Atwood tanks are glass lined thus no need for an anode rod.
MFL
Nomad II
Jun 16, 2019
Here is my take Rob. Yes to bypass, no anti-freeze in WH. I flush twice a year, in Fall and again in Spring. In Spring, after adding bleach to fresh tank, flushing system, WH still by-passed, I now open WH by-pass, and add the bleach water from fresh tank to WH, allow to sit over night, flush WH, and drain everything. Now add fresh water to fresh tank, drain fresh tank. Refill fresh tank, run through all faucets, and fill WH. I'm now good for the season.

If I am not going to use the camper for a few weeks, I drain the water heater. By draining, not leaving heater full, it seems to greatly extend the life of my anode rods.

I always keep some water in fresh tank, during season, and the black tank also.

I do put teflon tape on the anode, and keep it installed over Winter.

If you can understand this, I hope it helps! :)

Jerry
Chris_Bryant
Explorer II
Jun 16, 2019
The tanks are sprayed and fired, then the flame cup is welded in. It’s this final weld that needs protection.
The tank corrodes because of the action of heating the water, not just being wet.
midnightsadie
Explorer II
Jun 16, 2019
I pulled mine when new put in a quarter turn valve and a short spur nipple ,when done camping for the trip, I drain the tank ,and the holding tank, empty the poo tank. mine 13yrs old still making water hot.