Zinc Anode for Salt Water Pools, is that recommended?

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JoyfulNoise said:
there will be a competitor that will have less onerous restrictions on their heater that will make its lifecycle costs cheaper and service companies will be happier to service those heaters as it’s less involved.
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Most service companies decide which heater gets installed and most have a preferred manufacturer, so it is unlikely that any competitor will get any significant traction.

Other than Pentair, Hayward and Jandy, the only heater maker that has any market share of any significance is Raypak and they require an anode.

The manufacturers all get together to decide these things at a yearly top-secret meeting in Switzerland.

They just decided that the zinc anode will be required to have its own anode made of magnesium to protect the zinc anode from corrosion.
 
JamesW said:
The manufacturers all get together to decide these things at a yearly top-secret meeting in Switzerland.

They just decided that the zinc anode will be required to have its own anode made of magnesium to protect the anode from corrosion.
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And I’m sure all the corporations just purchased large holdings in the world’s major zinc mines too …

Why are the “evil lairs” always in Switzerland? Do they have some kind of national tax incentive in place to attract evil geniuses? Maybe everyone gets a lifetime supply of excellent chocolate if they move their evil operations there? 🤔
 
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The newest Installation manual requires 8 anodes made of different metals.

The zinc anode gets a manganese anode for protection, which gets an aluminum anode, which gets a magnesium anode, which gets a calcium anode, which gets a lithium anode, which gets a sodium anode, which gets a potassium anode.

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Ouch. I'm feeling like I need to redact that comment else I end up in a tough spot with Pentair.

I'm not going to attempt to regurgitate the reasoning I was given with specificity. Most corrosion issues are unsurprisingly excluded from the warranty because they have zero control over the circumstances that create said corrosion within the heater. If an anode exists, they may consider an effort was made to protect it and they look at our notes harder, and think about it slightly longer.

*Edited* to add; I.E. The state of the anode may be relevant to the report.

I should also clarify that all heat exchanger warranty denials require us to perform a full water chemistry analysis (test strips not valid), provide pictures of the header tubes, and inform the homeowner the reason. Obvious bonding issues are also relevant. Documentation is needed to ensure it's truly not Pentair's obligation if it's being rejected.

I don't speak for Pentair, but I believe they trust their reps to make good decisions based on good reports from their warranty stations. We see Pentair occasionally cover things they weren't obligated to, because they see the value in customer experience. You could argue this makes for an unfair rule set, but I feel it's a virtue. A human can extend grace if moved to do so, where the rule exacted consequence. It means an effort is made to consider variables. And with that comes the good and bad, I suppose, of the people involved to do it.
 
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bradgray said:
Ouch. I'm feeling like I need to redact that comment else I end up in a tough spot with Pentair.

I'm not going to attempt to regurgitate the reasoning I was given with specificity. I understood it in the context of the discussion. It more or less amounted to, most corrosion issues are obviously excluded from the warranty because they have zero control over the circumstances that create said corrosion within the heater. If an anode exists, they consider an effort was made to protect it and they look at our notes harder, and think about it slightly longer.

I should also clarify that all heat exchanger warranty denials require us to perform a full water chemistry analysis (test strips not valid), provide pictures of the header tubes, and inform the homeowner the reason. Obvious bonding issues are also relevant. Documentation is needed to ensure it's truly not Pentair's obligation if it's being rejected.

I don't speak for Pentair, but I believe they trust their reps to make good decisions based on good reports from their warranty stations. We see Pentair occasionally cover things they weren't obligated to, because they see the value in customer experience. You could argue this makes for an unfair rule set, but I feel it's a virtue. A human can extend grace if moved to do so, where the rule exacted consequence. It means an effort is made to consider variables. And with that comes the good and bad, I suppose, of the people involved to do it.
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Thanks for clarification. Pentair representatives have a right to look into the circumstances behind warranty claims as to confirm the failure is due to a Pentair defect.

It would be helpful if Pentair published the items to be reviewed to determine that the proper effort was made to maintain their equipment according to their manuals. Too much is left to individual representatives discretion which leads consumer to assume Pentair is looking for reasons to deny a warranty claim.

You do not need to feel you must respond and defend Pentair. We appreciate you sharing what you see on your side of pool care.
 
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I think there’s a few points to keep in mind -

1. I studied corrosion and worked in a corrosion lab as an undergrad (one of my mentor professors who took a keen interest in me becoming an engineer). Corrosion is an incredibly complex, and not-entirely-well-understood, set of chemical phenomena. Even under the most controlled circumstances in a lab you can have multiple reaction mechanisms causing “corrosion”. Materials and environment matter a lot and there is no one “catch all” explanation for any given process. And, just as varied, there is no one perfect solution to fixing problems of corrosion.

2. Pool heaters take a beating. Hands down they are the most stressed part of any equipment pad. It’s a big chunk of metal, plastic, and ceramics, parts of which regularly heat up to well over 2000F or more (NG flame temp is ~ 3,500°F). You also have highly mineralized and corrosive water flowing through the heat exchanger tubes. For those that use their heaters daily, you have a system constantly cycling through these temperature extremes multiple times for hours on end every day. There is no other piece of equipment asked to do so much on a regular basis. There is no comparing their workload with any other kind of heater/boiler system.

Given the above, I would suggest that Pentair, and all heater manufacturers, need to set clearer expectations on their products and installation. Most homeowners are not experts at any of this and rely solely on the people building their pools to do the right thing. There will always builders that cut corners or hire subs that aren’t properly trained to do the work. Pentair needs to be a part of that solution by setting clear expectations for their equipment installs and ensuring that a customer is educated in what needs to be done. Maybe it requires an independent inspection with a sign off checklist by a Pentair rep before equipment is commissioned into service. Homeowners can not be expected to know what is the right way of doing something and builders, by and large, will not spend their time on it unless they are forced too.

Pentair values customer relationships … ok, good. Then treat the customer with respect and help make their experience a positive one instead of coming in way after the fact and handing them disappointing news. As a pool owner, if you simply say “oh that wasn’t installed right…” or “you should not have used that kind of stuff in combination with our equipment…” then how does that help? I can’t go back in time and if I was told to do it the “right way” from the beginning then I would have …
 
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I don't feel a need to defend Pentair. I do feel a need to clarify my original comment, which unfairly approximates placing words into their mouth. Given the path of this discourse, I'll touch base with our rep and report back.
 
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I robbed our rep of his lunch hour and have an update. All-in-all, the suggestion "they are considered when looking at warranty" is technically true. However, I seem to have embellished to what extent these influenced verdicts. The discussion I had with Pentair originally about the topic, was specifically over a 2 year old MT400 with a leaking exchanger. Chamber was full of water to the ignitor. When we pulled the heater off the pad we discovered they had bonded the equipment to a metal fence, which was fully connected to another 1,000 or so linear feet of metal fencing in a townhome complex - with several other equipment pads bonded to this same fencing. When we brought this up as a concern, it triggered a question from our rep about whether an anode was present, and his comment about how this may have been helpful, which was an echo of our prior rep's comments on the topic. What was meant by them however, was that an anode would have revealed the problem much sooner, before cumulative damage took down the exchanger.

Thus:
1) Sacrificial anodes are not given value when determining whether a corroded heat exchanger is covered or denied.
2) At least some Pentair representatives believe a properly installed zinc anode has some value, as opposed to none.
3) Anodes are not officially claimed by Pentair to be inherently preventative nor protective, and subsequently are not in their literature. Though, this seems to be more about installation error or extenuating overrides, than their attitude behind them in general.
4) Anodes may be used by Pentair as correlative sign of bonding or chemistry issues. In other words, radical deterioration may be a first sign something is amiss. This was the key insinuation I misunderstood.
5) If an anode is present, and shows little deterioration, more investigative work is encouraged to determine if the age of the anode and exchanger are incongruous. This relates to the above.

And there we have it. I will edit my prior posts to include this amendment.
 
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I think that most have the zinc 3/4" NPT plug, but some might come with the plastic sealed and you have to drill out the hole to install a pressure relief.

It's really not a drain plug.

The drain plug is the plastic plug in the front.

The zinc plug is where you can install an optional pressure relief.

It is probably a good idea to remove the zinc plug to examine it for corrosion in cases of leaking heat exchangers.

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Yes. A hunk of zinc that is attached to or in contact with water but without a conductive pathway to close the circuit between itself another piece of metal in the water or the ground around it creates no galvanic couple. It’s essentially just a chunk of metal sitting water.
 
For an anode to work, you need a conductive path between the anode and the metal being protected.

When you have a metal that you want to protect, the anode provides electrons to neutralize anything that tries to remove electrons from the protected metal.

For example, if oxygen or chlorine made contact with the copper heat exchanger and tried to pull electrons from the copper atoms, the electrons could come from the anode and reduce the oxygen to oxide or chlorine to chloride.

The goal is to be able to protect the copper from losing electrons by providing an alternative source of electrons.

The zinc loses electrons more easily than copper, so the copper will be protected and the zinc will be preferentially oxidized and "Sacrificed".
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What does the plate look like that the copper heat exchanger pipes are connected to? How are the pipes connected to it and how is the plate connected to the tub? IIRC there’s some high temp RTV sealant used …
 
I thought so.

Bad design.

Copper in contact with steel, even stainless, will cause a galvanic couple to form. Copper-steel couples aren’t the worst you can have, but they are bad. Unless the copper tubes are designed with a galvanic transition layer (like household plumbing copper-to-steel adapters used on many hot water heaters), it’s going to cause problems. But it’s probably best, lowest cost solution Pentair can employ without making the entire combustion chamber out of platinum metal 😂
 
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JoyfulNoise said:
What does the plate look like that the copper heat exchanger pipes are connected to? How are the pipes connected to it and how is the plate connected to the tub? IIRC there’s some high temp RTV sealant used …
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Thick and heavy. The plate just sits against the tub and gets sealed with the manifold bolts. No RTV.

These are from out latest swap.
 

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