Magnesium Anode Rod in Garn

[bpirger]

Hi All:

I went through my single Mg anode rod in my Garn 1500 in the last 7 months. Wouldn't think it would be gone so fast....yet there it is (or isn't).

I see a replacement from Dectra is > $70. I see Mg anode rods from many others, apparently of similar size and length, are about $20. While I'm happy to support Dectra, I figure doing so with things like Gasket Kits and Flu Brushes might make sense....and using the much less expensive Mg rods from elsewhere would save a few $$$. Seems like warranty issues are moot since they don't provide a corrosion warranty anyways....

Anyone replace their rods? Any reason why not to take this route?

Thanks,
Bruce

 

[Kemer]

I had to replace mine also after less then a year

 

[heaterman]

There is a difference in the Mg content of the rod. I see the same thing in anodes used in commercial water heaters vs a residential model.

I have to say that the anode being gone (totally?) in one season would indicate an imbalance of some kind or maybe an electrical ground/stray voltage issue.

 

[Como]

I take it that all Garn's come with these but their rate of usage varies?

Can you fit more than one or a larger one if needed?

Sort of raises the question I guess as to when your water was last tested?

 

[Kemer]

I had my water tested twice so far.I have to believe heaterman that I have a stray ground issue

 

[bpirger]

My thinking has been that I have ground issues too? Harry said he used up his Mg rod in one season as well, so I was hoping it might be normal...and was hoping Steve would chime in...and sounds like it is NOT normal.

I have my Garn grounded by a ground rod driven in the ground under the drip edge of the garn barn....and bolted tight to the lifting flange (with the paint ground off) through the hole I drilled. The pumps have the ground wire tied to their casing. So is this a potential problem if there is a difference in the grounds? The ground wire to the pumps is likely 150' or so from its ground rod connection. So who knows.

I have no experience with Mg rods and all this, but it seemed like it was quick.

Garn installed in Nov, water was tested before the fill and a couple of weeks after the fill, dumped two buckets of the 200CLT or whatever they call it...and all was deemed fine by precision. Waiting to hear back on the second sample which I just sent.

So, all water tests were deemed good, before and after initial treatment, and things "look" good to me, but I don't know what I'm looking at. Don't see any rust.....good!

So perhaps I can measure between the ground rod ground and the pump wire ground to see what I might measure? Is it possible that the "first fill" would consume the rod more quickly then subsequent years, with the same water primarily in the tank?

 

[Frozen Canuck]

Not sure about the area you fellows live in but here it is very rare to see someone using a grounding rod only due to soil conditions (too dry) every electrician I know uses grounding plates only, due to the increased surface area (many times what a rod can provide.

They are not anything fancy just a large metal plate 3/8 or 1/2 about 24" square (or larger) with a grounding lug welded to them. I prefer to bury them 5' or more down where I know they will be moist at all times. Just a thought, if you use a low voltage source & tester & verify that the ground wire is OK as far as conducting is concerned then your rod(s) maybe dry & therefore unable to ground any source & therefore totally useless. Best to find out now before lightning or any other kind of voltage surge leaves you with the awful realisation that your ground was not working properly after the surge fries all the electonics connected to it. Garn, pump, controls etc.

Very pricey way to find out what a simple test can tell you now. If you are unsure/uncomfortable, call a local electrician, for the cost of a service call they should tell you in 15 min or so if the ground is conducting or not. Really the cheap end of the deal. You probably have more $$ in chemicals to protect the boiler/piping/pumps etc. No point taking a chance here when you consider the cost of being wrong.

 

[heaterman]

Not sure about the area you fellows live in but here it is very rare to see someone using a grounding rod only due to soil conditions (too dry) every electrician I know uses grounding plates only, due to the increased surface area (many times what a rod can provide.

They are not anything fancy just a large metal plate 3/8 or 1/2 about 24" square (or larger) with a grounding lug welded to them. I prefer to bury them 5' or more down where I know they will be moist at all times. Just a thought, if you use a low voltage source & tester & verify that the ground wire is OK as far as conducting is concerned then your rod(s) maybe dry & therefore unable to ground any source & therefore totally useless. Best to find out now before lightning or any other kind of voltage surge leaves you with the awful realisation that your ground was not working properly after the surge fries all the electonics connected to it. Garn, pump, controls etc.

Very pricey way to find out what a simple test can tell you now. If you are unsure/uncomfortable, call a local electrician, for the cost of a service call they should tell you in 15 min or so if the ground is conducting or not. Really the cheap end of the deal. You probably have more $$ in chemicals to protect the boiler/piping/pumps etc. No point taking a chance here when you consider the cost of being wrong.

Good advice!

Ground rods are pretty standard practice around here, due to mostly wet soils. I don't know about the areas where kemer and pirger are located.
Once in a while I'll see a job where the inspector "requested" multiple rods but have never seen a ground plate. I do however understand the concept of surface area and agree 100%.

 

[heaterman]

My thinking has been that I have ground issues too? Harry said he used up his Mg rod in one season as well, so I was hoping it might be normal...and was hoping Steve would chime in...and sounds like it is NOT normal.

I have my Garn grounded by a ground rod driven in the ground under the drip edge of the garn barn....and bolted tight to the lifting flange (with the paint ground off) through the hole I drilled. The pumps have the ground wire tied to their casing. So is this a potential problem if there is a difference in the grounds? The ground wire to the pumps is likely 150' or so from its ground rod connection. So who knows.

I have no experience with Mg rods and all this, but it seemed like it was quick.

Garn installed in Nov, water was tested before the fill and a couple of weeks after the fill, dumped two buckets of the 200CLT or whatever they call it...and all was deemed fine by precision. Waiting to hear back on the second sample which I just sent.

So, all water tests were deemed good, before and after initial treatment, and things "look" good to me, but I don't know what I'm looking at. Don't see any rust.....good!

So perhaps I can measure between the ground rod ground and the pump wire ground to see what I might measure? Is it possible that the "first fill" would consume the rod more quickly then subsequent years, with the same water primarily in the tank?

I can't answer that for you ........It could be an electrical issue, it could be the initial fill just settling down......?? Usually a galvanic reaction will occur on a joint where you have dissimilar metals so I don't think that is what you are looking at.
My personal opinion is that if the anodes are totally gone in one season something is amiss. My son in law just pulled his after 3 years and I would say they are maybe 50% of original mass.

 

[thecontrolguy]

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 pane, 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.

 

[Frozen Canuck]

Good catch by "the control guy".

I do recall at least one thread where this was mentioned (I sure hope it was not done the way it was written).

If anyone has not taken their ground wire from the rod/plate then to the electrical panel FIRST & then attached bonds from there out please do so ASAP, as the entire system/building could become energized, with really nasty unintended consequences.

Boilers of any type make excellent conductors as they are: 1) made largely of steel. 2) full of water.

BTW same applies to your homes for those of you that DIYed your houses.

 

[bpirger]

So yes, my panel that services the Garn has the proper ground wire out to two ground rods. The ground wire of the wire out to the Garn barn is tied to this ground lug in the panel....just as it should be. No worries there. The ground wire out in the Garn barn is tied to the "shells" of the 00R pumps, via the grounding scew, as they should be....and indeed, all the grounds are continuous thorought the system.


I also added, in the Garn barn, a dedicated driven ground rod and ground line from the rod to the Garn itself. So this is a "separate" connection to earth ground for the garn.

So the ground rods driven for the panel in the house actually tie to this Garn barn ground rod THROUGH the garn itself. So if there is any potentional on, say, the house ground system, compared to the Garn ground rod, then current will flow through the Garn. Now, one would think that the house's ground through the two ground rods is a "good ground" and all would be fine....no problems to date....and the Garn ground is the same potential as the house "ground".....i.e. ground....but I would agree with the consensus that consuming a Mg rod in 6 months indicates perhaps something is fishy.

I can try and measure the potential between the grounds. I will also talk to Dectra and or Mike at precision.

I wondered if connecting an additional ground rod to the Garn and connecting this to the house ground system was an issue. I understand ground isn't ground everywhere....and while we only have a foot or so of topsoil up here on the hilltops covering miles of shale rock....I don't know of any particular grounding problems....though I don't know....

Thanks for any and all comments!