I don't know what possessed me to check the anode rod in my 4 year old water heater with a 6 year, "guarantee" but it was gone...dissolved...useless. Home Depot. Order one for $18 and pick it up at the store 10 days later or get one in the store today for $25.

The anode rod is the thing that stands in the way of the tank leaking. It is very important to have one!

Now for some details: I have a short tank, so the blow-off valve is on the side. That means there are (2) two holes in the top which fit 3/4 MIP threads. The anode rod requires a socket of 1&1/16th inches or 27 mm. I couldn't get it loose with a breaker bar, and I'm no pansy. I had to use my 300 ft-lb torque wrench, and bounce on it, to get the threads to break loose. The other plug is 1/2 inch square drive and a second anode rod will fit in that hole. The anode rods are 42 inches when they are born, so I had to cut them off at 24 inches because the bottom of my tank is 26.25 inches below the threaded holes.

I have modeled a residential plumbing system as a bunch of resistances and figured out how to do the piping for a minimum of scalding in the shower when somebody flushes the toilet, but I have not analyzed why the anode rod gets eaten by the tiny currents caused by dissimilar metals. If anybody wants to play with that idea, feel free to post the explanation in this Thread.

 

I have not analyzed why the anode rod gets eaten by the tiny currents caused by dissimilar metals.

Could it be that water flow, plus the diluted salts in it, cause said currents? Quite a few years ago, I did a project for the maritime industry. I learned then that large ship propeller's blades are manufactured from bent, shaped and welded plates that form a hollow assembly. The internal space is not left empty, but is rather filled with oil to prevent galvanic corrosion. This because as the blade slices through the salt water it somehow acts as a generator. Maybe @atferrari can explain this better than me.

 

Could it be that water flow, plus the diluted salts in it, cause said currents?

My definition of a battery:
The EMF is caused by 2 dissimilar metals in an ionic solution.
The effectiveness of the battery is enhanced by the solution being any Ph except 7.
The current is enhanced by dissolved ions (like NaCl) in the solution.
There is nothing in that which mentions velocity.
Remember, I'm talking about a residence on land. I am completely ignorant about propeller velocity acting as a generator.

As usual, I am open to getting educated on this site.

 

Remember, I'm talking about a residence on land. I am completely ignorant about propeller velocity acting as a generator.

Yeah, maybe you're right and whatever role water flow plays in generating current might be negligible (or maybe non-existent?)... much more like a battery, as you've just mentioned... this is a problem whose electrical model or simulation should be very interesting to see.

 

Just the difference in the metals potential cause the current. It's like ionizing radiation is to us. It breaks the atomic structure....in this case...of the tank......down. All elements have a potential. O2 loves to ionize metals.

Many fields study this in great detail.

 

I don't know what possessed me to check the anode rod in my 4 year old water heater with a 6 year, "guarantee" but it was gone...dissolved...useless. Home Depot. Order one for $18 and pick it up at the store 10 days later or get one in the store today for $25.

The anode rod is the thing that stands in the way of the tank leaking. It is very important to have one!

Now for some details: I have a short tank, so the blow-off valve is on the side. That means there are (2) two holes in the top which fit 3/4 MIP threads. The anode rod requires a socket of 1&1/16th inches or 27 mm. I couldn't get it loose with a breaker bar, and I'm no pansy. I had to use my 300 ft-lb torque wrench, and bounce on it, to get the threads to break loose. The other plug is 1/2 inch square drive and a second anode rod will fit in that hole. The anode rods are 42 inches when they are born, so I had to cut them off at 24 inches because the bottom of my tank is 26.25 inches below the threaded holes.

I have modeled a residential plumbing system as a bunch of resistances and figured out how to do the piping for a minimum of scalding in the shower when somebody flushes the toilet, but I have not analyzed why the anode rod gets eaten by the tiny currents caused by dissimilar metals. If anybody wants to play with that idea, feel free to post the explanation in this Thread.

You are not the first to have trouble getting the thing loose...

From. https://www.familyhandyman.com/plum...r-heater-by-replacing-the-anode-rod/view-all/

To loosen the rod, you’ll need an air compressor, a 1/2-in.-drive impact wrench and a 1-1/16-in. socket. If you don’t have an impact wrench, go buy a cheap one for about $30. Even with a breaker bar, it can be nearly impossible to break the anode rod free.

...

If the hex head is set below the top of the heater, you’ll need a 1-1/16-in. socket to reach it. If it protrudes above the top, you can use any type of wrench. Chances are your old anode rod will be frozen in place by corrosion.
...

You may also have to slip a “cheater” pipe over the wrench handle to increase your torque. The weight of the water in the tank is usually enough to keep the entire heater from turning. But if it begins to move, have a helper (or two) hold it in place.

 

My definition of a battery:
The EMF is caused by 2 dissimilar metals in an ionic solution.
The effectiveness of the battery is enhanced by the solution being any Ph except 7.
The current is enhanced by dissolved ions (like NaCl) in the solution.
There is nothing in that which mentions velocity.
Remember, I'm talking about a residence on land. I am completely ignorant about propeller velocity acting as a generator.

As usual, I am open to getting educated on this site.

Before I moved into my 1950's house I replaced the plumbing with PEX, one pipe in the kitchen was a 2 inch Galvanized it was not coming apart I thought I would have to cut it out when the plumber came to crack my cast Iron Sewer drain to install a second drain for an upstairs washer drain I asked if he could suggest best way to do it. I was using a 4 foot cheater was just smashing the pipe deforming it, just wouldn't budge.

He came up and grabbed my sledge hammer and pipe wrench and smack the back of the pipe wrench a few times real hard, it loosened the rusted pipe threads and it came right off. I've done that ever since, works like an impact wrench.

kv

 

I replaced the plumbing with PEX,

One of the mysteries here is that I always connect my water heaters with a dielectric. It might be 4 inches of CPVC or 18 inches of flexible plastic with pre-installed ends. That leaves a steel water tank connected to an iron 90 degree angle and some plastic (at both pipes). How that takes out a anode rod is a mystery to me.

Wait...what about the copper wire bonding the tank to the copper pipes in the house and which connect to the iron pipes which are buried in the dirt? That is not a simple model in my mind. Of course, everything is easy, right after you know how. I simply don't know the answer to this one.

Anyway, job done, really quickly, good day for me. I'll check again in 3 or 4 years.

 

I'll check again in 3 or 4 years.

By all means... don't keep us in suspense...

 

One of the mysteries here is that I always connect my water heaters with a dielectric. It might be 4 inches of CPVC or 18 inches of flexible plastic with pre-installed ends. That leaves a steel water tank connected to an iron 90 degree angle and some plastic (at both pipes). How that takes out a anode rod is a mystery to me.

Wait...what about the copper wire bonding the tank to the copper pipes in the house and which connect to the iron pipes which are buried in the dirt? That is not a simple model in my mind. Of course, everything is easy, right after you know how. I simply don't know the answer to this one.

Anyway, job done, really quickly, good day for me. I'll check again in 3 or 4 years.

Has the Main Line to the house been replaced? Mine was so rusty I need to just replace the Hot Water Heater it's going on 12 years now, it was new when I purchased the house. Our water is class B very good quality spring water the problem is it's hard as h-double hockey sticks (Trying to cut down on my Swearing) now if I can control my drinking to one glass a week.

Anyway back on subject, so if your pulling in any Salt from ground water exchange from the Main line partial pressure laws play a critical role in the Chemistry.

https://en.wikipedia.org/wiki/Dalton's_law

In chemistry and physics, Dalton's law (also called Dalton's law of partial pressures) states that in a mixture of non-reacting gases, the total pressure exerted is equal to the sum of the partial pressures of the individual gases. ... and is related to the ideal gas laws.

Add some copper pipe dissimilar metals and we are tuning up a electrolysis roaching the pipe, same as a Manual Defrost Refrigerators Ice Box, the weld to the box is different alloy as what is made from the box or the tube and leaks eventually. But, you know that I think.

I could be really wrong, maybe someone else has a better reason?

kv

 

The dissimilar metals don't have to be in contact with each other......or even close to your house. You could have an entirely plastic plumbing system(even a well)......and still corrode the lining. You want the ions in the water to react with anode.....instead of lining.

You can also use chemical water treatment(i.e..pH control, etc) for scale prevention.

And they have a electric powered anti-corrosion systems.

 

Could it be that water flow, plus the diluted salts in it, cause said currents? Quite a few years ago, I did a project for the maritime industry. I learned then that large ship propeller's blades are manufactured from bent, shaped and welded plates that form a hollow assembly. The internal space is not left empty, but is rather filled with oil to prevent galvanic corrosion. This because as the blade slices through the salt water it somehow acts as a generator. Maybe @atferrari can explain this better than me.

From all what I know and recall from vessels I navigated on, propellers were always solid pieces of "bronze" (a complex alloy in fact), carefully balanced after taking it out of the mold.

Never seen sacrifice anodes of any kind on the propeller itself but profussely distributed, starting in the cavity housing the propeller and the rudder. Amongst the tens and tens of plans kept on board, there is one with quantity and location to be welded at different places on the hull and appendages when going to drydock.

In the past, it was common to have a spare propeller and a spare anchor on board. Nowdays, anchors only.

I recall two old vessels carrying even a spare intermediate shaft!!

 

I don't know what possessed me to check the anode rod in my 4 year old water heater with a 6 year, "guarantee" but it was gone...dissolved...useless.

Well thanks a lot. My heaters are over 25 years old and I’ve never checked their anodes. One more horrible chore for my list. Terrific.

At least I know not to bother without borrowing a breaker bar first.

 

Never seen sacrifice anodes of any kind on the propeller itself but profusely distributed,

I saw a movie where the, "bad guys" were smuggling something in the sacrificial anodes of a ship. Might have been a James Bond movie...or not. I'm mostly glad I don't need to figure out how to weld zinc or magnesium to an iron boat.

Has the Main Line to the house been replaced?

No. 3/4 iron pipe. The meter outlet will blow 28 GPM, but after 150 feet of nasty old iron pipe, I get 7 GPM at the house.
It's enough. 3 GPM is sufficient for most anything in a residence.

At least I know not to bother without borrowing a breaker bar first.

I like the 1/2 inch air gun idea. Those things can slam hundreds of foot pound pulses into a nut without spinning the tank. I fix cars, so I have that equipment. Maybe you don't.

The dissimilar metals don't have to be in contact with each other......or even close to your house.

So...figuring out how it works won't fix anything. I guess I'll just keep replacing anode rods.

ps. I finally got an answer on my Fluke 27. No parts available. Odd. When I phoned Global Test Supply they knew all about Fluke 27's and had parts. After I paid for shipping and waited 3 weeks for an answer, they can't get parts. Now I have to look at the, "best meter" Threads here and buy a replacement. (Those $4 Centek meters from Harbor Freight are a pitiful excuse for a meter compared to an old Fluke.)

 

I saw a movie where the, "bad guys" were smuggling something in the sacrificial anodes of a ship. Might have been a James Bond movie...or not.

It sounds funny if not ridiculous because unless specifically required after an accident / collision, nobody goes down there, much less with welding / cutting equipment what would arouse LOT of interest in crewmembers first of all. Seamen have spent centuries figuring out how to smuggle things into the vessel with varied results going from funny to tragic.

I know someone who, vis-a-vis Customs regulations abroad and scared of running out of cigarettes at sea, used to hide cartoons everywhere from lifeboats to the standard compass. Until one day he decided to quit smoking.

Now I feel better. Much much better.. but then, coffee.

 

ps. I finally got an answer on my Fluke 27. No parts available. Odd. When I phoned Global Test Supply they knew all about Fluke 27's and had parts. After I paid for shipping and waited 3 weeks for an answer, they can't get parts. Now I have to look at the, "best meter" Threads here and buy a replacement. (Those $4 Centek meters from Harbor Freight are a pitiful excuse for a meter compared to an old Fluke.)

5-years ago there were Fluke parts all over eBay. Either the sellers ran out of energy to ship $6 and $12 parts or their inventory dried up.

I don't know what happened.

I have a 1983 Fluke 8025A -the first handheld digital DMV with the mil-spec carrying case. I replaced the display and selector switch for $15. Now they are nowhere to be found. I hope nobody drops mine (unless it is in the indestructible case).

 

Could it be that water flow, plus the diluted salts in it, cause said currents? Quite a few years ago, I did a project for the maritime industry. I learned then that large ship propeller's blades are manufactured from bent, shaped and welded plates that form a hollow assembly. The internal space is not left empty, but is rather filled with oil to prevent galvanic corrosion. This because as the blade slices through the salt water it somehow acts as a generator. Maybe @atferrari can explain this better than me.

Actually, that's entire PURPOSE....to get eaten away rather than the tank!

 

Actually, that's entire PURPOSE....to get eaten away rather than the tank!

Yeah, I get that... but I'd like to know the science behind it

 

I like the 1/2 inch air gun idea. Those things can slam hundreds of foot pound pulses into a nut without spinning the tank. I fix cars, so I have that equipment. Maybe you don't.

I don't, but I was thinking about impact versus 'slow' torque as I was writing that. The pipe wrench-plus-BFH (Big EffingHammer) solution might be a better approach, and I already have those.

 

Typo?

BFH (Big EffingHammer)

That would be BEH