anode in buffer tank?

scott markle_2

I'm thinking about using a small electric heater as a buffer tank. Parallel piped with mono-flow T's.

Does anyone see any potential issues with a tank anode in a closed loop heating system. Could the anode do more harm than good?

Unknown

Remove the anode?

It might be a good idea to remove the anode in a closed loop application and replace it with a threaded plug. As the anode reacts with the water electrochemically, it forms aluminum or magnesium hydroxide which is a white powdery material. In an open loop system, the substance is continually flushed away, but in a closed loop the powder might accumulate and tend to coat surfaces or clog small water passages with a slimy mess.

But I guess keeping the anode would not be any worse than having a boiler with an aluminum HX!

scrook_2

unless...

it's a magnesium anode. Can't see it hurting or helping either way, guess I'd just remove it and plug the hole anyway though.

scott markle_2

I think I can handle a little precipitate it will probably just stay in the tank. I can kind of imagine my plug ending up as a corrosion point.

hot_rod

It provides a great hole

to use for a gauge, pressure or temperature, or a 30 lb pressure relief valve.

It's a great location for an auto air vent as most WH have a domed top and collect air nicely.

Or an additional supply outlet to pair a couple together, for higher flows, like a geo buffer tank.

It may void the warranty to remove it, should that ever be a concern.

But in a closed loop, sealed system I don't see a need for it.

They can be a bear to remove, find a 6 point socket and a breaker bar.

hr

Larry Weingarten

It might be time...

... for some scientific research. My experience with anodes (magnesium) in closed systems is that they corrode away in a normal manner and help keep tanks going. Sadly, I only have a few situations I've kept track of long term. In theory, no oxygen should prevent further rusting, but that is not the only mechanism eating steel tanks. I vote for keeping a mag anode in place. Put in a combo style and you can then add anything you wish to the outlet :~)

Yours, Larry

ps. I should add that there is a good book by Fontana and Greene called "Corrosion Engineering". It's third chapter on eight forms of corrosion is the clearest description of the processes I've seen. I see they range from $3.36 to about $172 on www.addall.com !