Garn Anode rod

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Kemer

Member
Feb 26, 2008
213
Northeast Pa
I just found out than my second anode rod is gone.I'm told I must have a stray ground.I will call my power co.to see if they will come out and check things out.Any body know how I can track this stray ground? My water was checked twice and came back Ok.I also ground and drilled a hole in the ear of the garn to make my connection to my ground rod but I used the ground rod from my back up generator.I was told by an electrician that would be ok.Maybe not?
 
Harry - a "stray ground" is not a problem. You want to make sure you have a very stable ground between the GARN and a ground rod/plate AND the electrical panel feeding the GARN power. The consumed anode rod is doing its job, but the cause for rapid consumption is often water chemistry. Did you contact Precision Chem? Did you note the anode rod consumption on your last sample sheet?
 
I'll speak for Harry here in the interim and say yes, it was Mike at Precision with the water test. I too had a rod consumed in the first year, first 8 months really. Harry, do you have the garn connected to the ground from the panel? Is it just through the pumps or directly? I know I had my Garn connected to a driven ground rod (drilled a hole in the flange and ran a #8 copper wire to it). But my ground coming from my panel was NOT conencted to my pump initially....my make shift temporary wiring for a year didn't carry the ground to the pumps...to I just had the Garn connected to the ground rod...and not to the panel ground. Now maybe somehow that was causing a small current to flow? I don't know.

I now have my panel ground connected to the pumps (and presumably through the plumbing to the Garn) as well as the ground rod. I wonder if I should remove the ground rod connection and have just the panel ground? It is a 12AWG wire going about 100' from the panel connection. If there is a difference in the ground connection from the plumbing and the ground rod, a potential, then I can understand how this could cause a current to flow...and hence the consumption of the rod....

I too had two water checks just fine and noted the rod was gone....and just heard replace the rod. I just added a couple hundred gallons of water to the Garn, my next test is in 6 weeks or so...everything looks good inside to me...so I will find out what the story is then.

If my second rod is consumed as fast as the first, I think I'll remove the ground rod connection and see if that helps (ground coming only from the panel then). It might not be OK to tie the panel ground to another ground rod through the Garn anyways from an electrical code point of view. Yes, there are ground rods driven at the panel as well.
 
I did note to Precision that I used up a ground rod when I sent my second test in.My second test came back OK.When I talked to Kieth at Garn He said it more then likely was a ground issue.
He claims that in rural areas that stray ground effect milk farmers and there cows won't produce milk and that power co. are familiar with stray grounds and have equipment to trace them down.I doubt they will do it for free.I will call to find out.Kieth also said rods should last 7-8 years. I'll post as soon as I find out anything.Does any one know where to get cheaper rods?

PS Garn owners Kieth also told me they have a baffle to fit in the last tube to increase efficiency and reduce sparks.I ordered one approx.$70.00
 
Kemer said:
I just found out than my second anode rod is gone.I'm told I must have a stray ground.I will call my power co.to see if they will come out and check things out.Any body know how I can track this stray ground? My water was checked twice and came back Ok.I also ground and drilled a hole in the ear of the garn to make my connection to my ground rod but I used the ground rod from my back up generator.I was told by an electrician that would be ok.Maybe not?

Kemer, et al;

I'll quote myself from another post regarding auxiliary bonding connections to ground. I don't mean to be preachy, but I am also a Power Engineer, so I also know a few things about pipe corrosion from stray currents and dissimilar piping connections, and poor water chemistry, but situations like this where the anode device is consumed so quickly is almost ALWAYS linked to stray ground currents. Please be sure to note the terminology in that; the issue is not necessarily a bad ground, but certainly electrical current flow to that ground.

Folks;

As an electrician, it causes me some concern that a GROUND rod was driven and tied to a lifting lug for the Garn.

I am not sure how the building is serviced where the garn is located, but the GROUND is to be tied to the electrical panel ONLY, and anything metallic in the building (such as gas lines, water piping, etc) should be tied to that ground (and is henceforth called a BOND) to ensure none of these systems can become energized. This BOND wire is run seperately from the metallic piping back to the load compartment of the electrical panel, electrically bonding the two together.
What you may have there is a ground-current path from a potential ground-faulted device that may be travelling through the structure of the Garn and into the ground rod as electricity will follow the least-resistive path back to ground. Stray electrical currents can not only cause enormous corrosion issues, but can also get people electrocuted from stray voltages. Were I you, I would disconnect the ground rod from the Garn, ensuring that all electrical wiring to the Garn has a proper bond wire and that the bond has been made continuous throughout all the splices and junction boxes. Then I would find the electrical panel that services the building in which lives the Garn, and open the panel cover (service side) and ensure that there is a ground wire present and it is connected at the propoer location in that panel. Next, follow the grounding wire (heavy, usually green covering or bare copper) from that panel and ensure that it is connected to a good grounding device. In my case (Canada) we can use two 10 ft long ground rods, driven 10 ft apart, or a certified ground plate, buried at least 3 ft.
All circuits that come from that panel, such as those that serve your pumps, etc. should have a BOND wire that connects the metallic bits of the devices being energized back to the electrical panel BOND BUSS. This is usually a row of uninsulated terminals mounted in the load compartment of the panel box where all the other bare copper bond wires are tied to.
As usual, if you do not feel comfortable doing this, find a qualified electrical friend and lure him/her to your spread with the promise of BBQ’d vittles and some brew. Safety is paramount!
Cheers.
 
Thanks ControlGuy. So you are saying only one connection to the Garn, through the electrical supply wire to the pumps.

So is the idea that this additional ground rod then causes a potential across the Garn becuase of different potentials from where the ground rod at the Garn and ground rod at the panel are driven?

Is there some kind of ground fault that happens through the pumps? In other words, is there any way for some amount of current to flow from the pump hot wire back to the panel ground, but in a small amount? And when tied to an external ground rod, the flow goes though the GArn and not back to the panel?
 
bpirger said:
Thanks ControlGuy. So you are saying only one connection to the Garn, through the electrical supply wire to the pumps.

Yes, only one BOND connection from the Garn to the electrical panel. This is usually the bare copper wire that is in the cable that supplies 120 VAC to the fan and whatever else is on the Garn. This wire directs any short-circuit current (or ground-fault current) back to the electrical panel. In the case of a fault, like a pinched cable, the fault current conducted through the bond wire to the panel is intended to trip the breaker supplying that circuit. If there is no bond, then the metallic parts become energized, waiting for a path to ground. (likely when you grab the handle to open the feed door, etc)

bpirger said:
So is the idea that this additional ground rod then causes a potential across the Garn becuase of different potentials from where the ground rod at the Garn and ground rod at the panel are driven?

Essentially, yes. It could be currents induced in power cables (or low voltage wiring) that is referenced to ground and the actual in-ground loop from one ground rod (at the Garn) back to the ground rods (or plate) at the panel, and then back to the Hydro wiring that serves your building. Someone mentioned farmers and dairy; this is a potentially very complex bonding situation with lots of metal stanchions, pumps, pipes, lights, structure, etc. All these metals can have different electrical potentials relative to ground, and the CODE says to attach bonding wires to all metal parts and bring that back to ONE reference point. (the service ground) It is amazing just how sensitive animals are to stray electrical potentials. (I guess if we walked around in mucky ground saturated in conductive saline urine in our bare feet ...)

bpirger said:
Is there some kind of ground fault that happens through the pumps? In other words, is there any way for some amount of current to flow from the pump hot wire back to the panel ground, but in a small amount? And when tied to an external ground rod, the flow goes though the GArn and not back to the panel?

Could be anything. All copper wiring, piping, steel structure, duct work, etc, are antennas that can pick up EMF and conduct currents. When a plumber hooks up a new hot water tank, they use galvanic isolation fittings that isolate the copper pipes from the hot water tank. This to reduce the incidence of galvanic or stray currents causing galvanic corrosion in the hot water tank. Then the electrician comes along and puts a bond clamp on each of the hot and cold pipes, gas piping, etc so that no metallic items can become energized accidentally and cause stray ground faults. The trick is that all bond wiring MUST be brought back to the same single reference at the electrical panel. Entire engineering careers have been devoted to bonding / grounding issues! Especially related to lightning ...

For example; I have seen a low voltage control panel in a hot tub where the 24vac low-voltage control circuits (relays) were referenced (one side tied) to the metal control box. This caused the A/C supply breaker (a 40 amp GFI 2-pole breaker) to trip. We're talking maybe 5 milliamps.! This was UL and CSA certified! Anyway, there are many electricians, good at quick and efficient installs, that have no real understanding (or interest) in these finer aspects of their trade. This does affect other trades as well, especially plumbers, Gas fitters, HVAC techs, and sheet metal folks. All of these are either serviced by electrical power or near it and are required to be bonded to the electrical ground system.

I hope this helps!
 
Start with the easiest thing - you said your guy told you the water was "good". Define "good". What made it "good"? .

One question - does your installation contain any copper? Pipe or baseboard?
 
Garns come "equipped" with a lifetime of twice a year water chemistry checking by Precision Chemical, I believe in WI. They have a relationship with Dectra, the Garn company. From all accounts on this site, they are very good. SO every 6 months we send off a sample and they recommend what to add, if anything, into the Garn.

My Garn water sees about 10' of 1.25" copper pipe, along with some black iron pipe. Black iron is attached to the Garn itself, then brass ball valves, then the copper, then the HX, and the same back (in reverse, copper, brass ball valves, black iron)

Thanks Control Guy. SO it seems very likely then that Harry and I are both suffering from having the ground rod attached to the Garn, as well as the bare wire in the AC supply wiring....

Presumably Harry we should make sure that we have good continuity from our AC power GND line to the Garn itself, presumably through the pumps/plumbing, though perhaps a dedicated wire to the Garn "ear tab" we drilled and bolted directly to the AC power bare copper line? And then remove the connection to that ground rod. That way we have a single point connection back to the panel....

Does it make sense ControlGuy to connect a wire directly from the AC supply bare wire to the Garn, replacing the connection to the driven rod located out at the Garn? Then we don't rely on the connection through the pump housing, plumbing, etc. to the Garn. Everything is tied to the supply bare wire...no ground loops.
 
Why do these garns have anodes when boilers with storage don't? If you are putting steel tanks in your house you want them to last as long as possible. Why no anodes in all these storage tanks?
 
Generally in pressurized vessels, the air (and oxygen) are eliminated from the system, and no more can enter. Therefore, there is usually minimal concern of oxidation. The Garn is a big tank of water open to the air...there's a "manhole" cover on the top you can enter to go inside. So, air is always free to enter. Hence, the oxygen in the water can cause corrison issues. Or biology in your water can cause issues...or other things. This is why you want your radiant tubing to have an oxygen barrier, to prevent air from entering a system.

So with the Garn, or any open system that is encased in steel, you need to monitor the water chemisty and add additives to prevent oxidation, life, etc.

Now, some will say that you should test the water inside your pressurized boiler as well, or else you could run into long term problems. I think it is a good idea from time to time, but generally I suspect it is every few to 5 years, not twice a year. If you find a boiler which is constantly letting in fresh water, due to a leak, then you will find that boiler will likely rot and corrode very quickly, becuase there is always oxygen entering the system. Not a good thing! Other things in water chemistry can also cause problems....but generally, pressurized systems are much less susceptible.
 
Any outfit that won't share the analysis with is shady.

Even if the copper is isolated from the system with dielectrics, it still corrodes (albeit much slower) as the copper slowly dissolves into the water. Being an open system, the presence of O2 & CO2 accelerates this process. Add long periods of high-temp circulation (winter) and long periods of low-temp stagnation (summer) and you have a perfect corrosion machine. I stopped using copper in heating systems and could probably start a full-fledged business repairing copper-based corrosion in residential HVAC systems but I hate cleaning up other people's messes. I do it sometimes to spread the word that copper is evil and should never be used in hydronic systems unless you design an all-copper system, but I'm a voice in the wilderness right now. The proof is extensive pitting/grooving in the first few inches of iron after the iron/copper connection. Putting brass in between is not sufficient. The anode rod simply has a lower galvanic potential than anything else in the system and once consumed, the attack will continue at the next weakest link (copper/iron joints or depending on the alloy, the boiler shell - not good.) Keep in mind that is only where the attack will be concentrated, any iron/steel parts will be corroding, just at different rates. At 0.85V potential difference, copper/iron galvanic corrosion could very well masquerade as a ground issue. Virtually all dissimilar metals can develop a potential between themselves and hence corrode since boiler water is a decent electrolyte. The solution is to use the same material (iron/steel), compatible material (brass/bronze) or inert material (PEX/EPDM) throughout the installation. This is best practice but few people follow it and hydronic suppliers seem bent on introducing a whole rainbow of exotic materials into the marketplace with predictable results (galvanic corrosion).

Your anode did its job, replace it to buy time and good luck.
 
bpirger said:
Does it make sense ControlGuy to connect a wire directly from the AC supply bare wire to the Garn, replacing the connection to the driven rod located out at the Garn? Then we don't rely on the connection through the pump housing, plumbing, etc. to the Garn. Everything is tied to the supply bare wire...no ground loops.

BP; If I were you, I would disconnect the extra ground rod connection from the Garn. I am not that familiar with the Garn but I believe that there is a draft inducer fan right on the Garn and it is 120Vac. The cable that supplies the Garn has a bond wire, that once connected to the connection box of the fan should be then connected to all the steel of the Garn through the bolted connection of the fan electrical box to the fan chassis, through the bolts, to the Garn body. This is the 'bond' connection to the ground at the electrical panel. You may also need to examine the piping connections from the black iron to the brass / copper. There is a dielectric potential at these connections but that shouldn't be bad unless the water chemistry is aiding the galvanic current flow, or you are having the problems exacerbated by the connection to the grounding rod. You might also consider that the chemicals you were sent to add in the water for your initial setup are likely only to protect the iron / steel bits of the Garn. All the copper and brass parts need different chemicals that bond with the exposed surfaces of the interior of the piping to protect the other metallic bits. These are more expensive, typically, and you don't get them unless you ask. Also, the anti-oxidant chemicals are consumed over time in protecting the steel surfaces. There are items I've used in boiler systems that are 'tags' of different metallic composition, that you put in a fixture in your piping. Over a period of time, the tags are removed and sent to the supplier where they are measured to see how much of each tag has been consumed. This gives a picture of what's going on over the entire system and the amount and type of chemical can be extrapolated from there. To be fair, my experience has been typically with large close-loop systems, in power plants, but the corrosion and mineral deposition in the boilers is always a challenging and vexing subject. Good luck. Jim
 
I just checked my anode rods to re-confirm that they are still full length and show a minimum of corrosion. I put my Garn into service 12-21-2010. I might add that I have used it continuously, it does not sit idle, as I heat my domestic water in the summer months.

I did not use a separate ground rod but chose to make sure all connections were bonded back to the panel. The panel grounding bar is connected to a ground rod driven in the drip line of my workshop.
 
I just removed the connection to the ground rod at the Garn barn and confirmed I am indeed tied to my ac ground, er bond wire. SO, this is certainly a new situation for me and I will see how my rod handles it. It is essentially brand new...so I should be able to see consumption quite clearly.

I too have been burning the Garn non-stop since 17NOV10, using it for DHW all summer burning every three of four days with crappy spruce I had to clear to build the addition.

I don't question corrosion issues at all, and they were my number one concern with the Garn, except the price, or perhaps especially considering the price. However, I have yet to see a boiler system anywhere that doesn't use a large amount of copper in it, and personally I have never seen a boiler fail prematurely from corrosion without a "stupid" problem, like a constant leak. Now, I'm not in the industry and my view of such things is limited likely to say 15 residential systems, but they have all been apparently operating OK for their anticipated lifetime....and some I have seen are way beyond what I'd call a lifetime...40 years or more.

I do believe that in industrial systems the level of monitoring and control is massively advanced compared to residential systems. But as far as I know, there isn't such things in place in residential systems. Am I wrong? Do people do annual boiler water checks on their oil/gas boilers? Are there tracers used similar to wear metals in machinery in residential systems, or the industrial system you mentioned control guy?


I have heard of inherently nasty water in some areas of the country that will quickly attack copper, but I'm under the impression that in general, a closed system is quite robust (as long as it has no leaks). I think domestic water has been plumbed for many decades in copper, largely without issue, except for those few locations of particular water chemistry. Is this not true? Granted, these systems are largely entirely copper.

As for the open system, many Garns have been in place for quite a long time, and reportedly, as long as they are maintained with the chemical program, they have held up extremely well. One user here last year reported a major corrosion problem, but he also largely accepted responsibility in that his water sample testing was acquired a few hundred feet from the Garn itself, and it is believe that biology was in his tank and biological corrosion caused big issues. He operates a chicken farm, so it is quite feasible how this happened. A very thorough cleaning was done, from inside the Garn, and far as I know he's back in operation. Otherwise, with proper chemical monitoring and treatmemt, Garns have historically been rather robust. Of course I'm always interested in learning new things...and if there is a better approach to water chemistry, I'm open to listening and learning. Precision Chemical in WI, the folks who have a deal with Garn, has reportedly been very good and top notch. Heaterman here has installed many of these beasts, and sees many all the time. His experience on this topic has been invaluable, and hopefully he'll have a moment to chime in.

Every now and then this issue appears to rise, and there are experts out there who do this all day on a much grander scale, so learning from you would be ideal. But there also has to be a "tempering of reality" when it comes to association with the industrial strength vs. residential. I agree PEX would be apparently a great way to plumb an entire residential system, that's what I have in my floors and all my domestic water. But I also would have to think there are millions of miles of copper installed in the US, and generally it all seems to outlast the boiler, which themselves seem to live a very long time. There are always exceptions...and please let me know what I'm missing.
 
Thanks guys for all the input.I too have run mine all year for hot water.Is there a way to check for ground if I choose to remove my ground off the rod? I have a newer home with what I think is quality wiring installation.The one thing different with my system is I used the ground rod from my 17Kw standby generator that is connected to a auto switching panel.This was also installed by a reputable electrician.The garn is hooked up to my Gen so I can't see how I can isolate it from the same ground circuit that the ground rod is connected too.
Keep up the input.I will forward this to my electrician and see if I can get to the bottom of this.

Harry
 
Harry,

I measured from the AC ground wire to the Garn and assured that I was connected to the panel ground. This doesn't really give you any indication of quality of ground, or if there is a potential difference. Presumably I could use the same meter to measure for a potential difference between the line ground and the Garn, the line ground and the driven ground rod, etc.

Is that a suitable test to perform ControlGuy to find a "stray potential" between the panel ground (bond) and that of a driven ground rod located out at the Garn barn building? Presumably if you have a potential here, than the Garn is the "short" between the two, and hence the consumption of the anode rod will be drastic, since there is a current flowing through the Garn itself.
 
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