Does temperature affect SWG cells when winterizing?

[PoolGuyNJ]

Note: Modified Topic title.

AFAIK, temperature drops can effect the bond of the coating to the plates. The two have slightly different expansion and contraction rates. While Ruthenium is a metal, Ruthenium Oxides are crystalline and is used to prevent corrosion. Because it's crystalline, the formation of micro cracks in the coating is possible when stressed by the differences in the expansion and contraction rate.

While this may not immediately create a failed cell, and in fact, usually doesn't, when the cell is brought back on line, the flow of water through it is generally somewhat turbulent. This turbulence will generate some additional eroding friction and vibrations. Guess what happens to the coating's micro cracks? They may grow or expand.

Bringing in the cell in the winter may reduce the some of the stresses a cell's coating faces. As long as the cell isn't tossed in the bottom of a closet where the kids may bounce it around looking for their missing glove, the coating will not face the increased brittleness of it's crystalline nature vs. expansion/contraction characteristics of the plate metal, regardless of the small amounts of stresses involved.

Larger and more important factors in cell life are chemical and friction erosion. But everything that we can do to extend our ROI, should be.

I did try to get real numbers with respect to hardness, brittleness and temp relations on Ruthenium Oxide but was not able to find any.

I do have several customers with older cells (i.e. greater than 5 years) that have been bringing in the cell diligently. They also watch their chems.

Scott

PS/Side Note: Any idea why Autochlor's support page says:
How does the AutoChlor system remove calcium build-up on pools?

By extracting excess hardness (calcium etc.) from the water during the electrolytic process. This improves the feel of the water, protects the pool equipment and saves you money.

 

[JasonLion]

Do you have any evidence to support this? I have never heard of this effect, nor has a single case of this actually happening ever been reported on the board before. The last time you brought this up, a fair number of people posted contrary evidence. If you can support your assertion I would like to hear about it.

 

[Strannik]

Re: Cell replacement

AFAIK, temperature drops can effect the bond of the coating to the plates. The two have slightly different expansion and contraction rates. While Ruthenium is a metal, Ruthenium Oxides are crystalline and is used to prevent corrosion. Because it's crystalline, the formation of micro cracks in the coating is possible when stressed by the differences in the expansion and contraction rate.

I thought we already had this discussion...

Ruthenium Oxide is used as a catalyst, that's a main purpose of it. Plus ruthenium oxide is not the only part of the coating, it's more of a ceramic coating than crystalline. By the way, when you say expansion/contraction rates are different, do you know what they are?

Sudden temperature drop (50C within minutes) would probably affect it, winter/summer changes - won't. The water flow by itself won't affect it either. You can leave the cell turned off for years with pump running, and when you turn it on it will still be working.

Bringing the cell inside certainly wouldn't hurt it, but I wouldn't go as far as claiming it will extend the life of the plates.

Now I'm going to put a disclaimer here, I'm talking about quality coating manufactured by Australian, American and European companies. With Indian and Chinese manufactured anodes anything is possible.

PS/Side Note: Any idea why Autochlor's support page says:
How does the AutoChlor system remove calcium build-up on pools?

By extracting excess hardness (calcium etc.) from the water during the electrolytic process. This improves the feel of the water, protects the pool equipment and saves you money.

When you ask "why", what exactly do you mean?

 

[PoolGuyNJ]

WRT to the Autochlor support page, I suppose I should have asked them. It just seems like a silly thing to say.

WRT to the earlier post, I am duplicating my response to the Over sized Salt Cell thread.

What is being said is contrary to what I was taught, that it's not necessarily how hard you drive the unit but is the combination of the factors of power, water friction, chemistry and temperature changes that effect cell life.

The temp concern is not a rapid change type, such a condition is not normally encountered. With the exception of water, AFAIK, all matter expands and contracts at specific rates and amounts as temps rise and fall, respectively. The difference when two different materials are bonded, so there is direct contact, will stress that bond.

In the case of, say, a bimetalic strip as used in a thermostat, the strip will bend a measurable amount due to their being ductile. In the case of a cell blade, one of the two materials, the metal or the coating, and I don't know which, one will shrink more than the other. This will stress the bond. It has to. Ruthenium Oxide, according to my having Googled it for some time, last night and this morning is in a crystalline form when used for cell manufacturing. If the makers of cell blade use a ceramic matrix to bond it to the blade and it has some kind of elasticity, I can see it surviving. Neither ceramics nor crystals are my areas of expertise but I have never heard of either being ductile or elastic.

I do know that crystals have aligned molecules or atoms, depending on whether they are elemental or molecular. Many ceramics are not, such as most glass but many are. Exert pressure on either and they break along fracture lines. Some ceramics are partly crystalline.

My understanding is the coating is to prevent corrosion, not some catalytic process. The electrical current that flows between each set of plates, if no salt was in the water, would simply produce Oxygen and Hydrogen. Since we want chlorine, we add salt. The same charge splits the salt molecules as well as water molecules. The use of the coating is not to protect the titanium blade from the chlorine being produced, but rather from the caustic byproducts that cause our pH to rise. This may one of the more significant factors in a salt cell's life and by spreading the generation over a larger surface, may result in a longer continuous use life. That being said, since many close their pools due to cold weather, the temp concerns, I think are still valid.

I am not a scientist. I am a pool guy. I am not qualified in stating definitively, with credentials, reports, research, etc... usually disclaimer stuff. I have been taught and I have looked for information, just as any one of us can do. I know I have customers that don't want the cell brought in at closing and those that do. I know I have replaced the cells of those haven't brought them in, both cells my then employer sold as well as others. I know I have yet to have to replace any of the cells I have been bringing in for years. The number of them is not large, maybe 6 or 7 so, IMHO, that doesn't make for a definitive sample, yet. If the cells for those customers last another few years, they will be approaching the 10K hours of use. That makes me go hmmm.

Scott

 

[JasonLion]

PoolGuyNJ, do you mostly, or exclusively, work with Pentair products? The Pentair cell design is different from nearly all of the other companies. Pentair includes a significant portion of the electronics/user interface as part of the cell, while nearly every other manufacturer places the electronics/user interface with the power supply. This could lead to additional failure modes that don't really have anything to do with the cell plates, but instead involve the electronics package.

 

[PoolGuyNJ]

My personal preferences do lean towards Pentair. However, there are a lot of times when it's not the in the customer's best interest and that is where my priority is. While a Pentair may work well, it may not work best for a given situation.

As an example, if a customer has a Hayward Astrolite and the fixture has been holding water for a year, it's toasted. I am not going to suggest a Pentair fixture, even though it will work and fit. It's not UL certified for that niche. If a homeowner has a older Jandy RS8 and his pump died, I'm going to ask him if he wants to U/D his control board to use an E-Pump or just a 2 speed, assuming there is a space for the 2 speed relay to save on the power bill or just a replacement pump or motor, as the case may dictate.

Does being straight cost me potential revenue? Yes, but I like who I see when I look in the mirror. The revenue will come because this type of attitude is not found every day. Some people can't be pleased or will try to scam me. They may get me once, never twice. I thank them for the opportunity to be of service and suggest that they might be better off with someone else providing for their service needs. I like my customers and they like me. I like that just fine. Trust is a powerful thing.

WRT to the Intellichlor, I like the electronics on the cell. It keeps them cooler than in a control panel with the transformer and bridge rectifiers and limited air flow. Any replacement cells get new electronics. The latest spin of h/w has addressed all known issues, such as the phosphate shutdown issue that was problematic for Intellichlors and confusion with LED indicators. While there is more in the cell, overall, they have proven themselves. Look at Hayward's cells. The cell is lasts but the board overheats in a known place and has a dedicated end user sponsored web site with the fix. Jandy knows their bridge rectifiers don't dissipate heat well and their transformers fry. Have they done anything to fix it? Not that I know of. Let me add that it is possible they have and I just haven't seen it yet.

Scott

 

[spishex]

IMO Pentair is also easier to access for technical support. For me, if there's a toss up between a Pentair product vs. a Hayward or Jandy unit I'll go with Pentair because I know if I do end up with an issue I'll at least be able to get someone knowledgeable on the phone without waiting too long (usually ). Or I can drive 1.5 hrs to their offices and bang on the door!!

 

[Strannik]

WRT to the Autochlor support page, I suppose I should have asked them. It just seems like a silly thing to say.

We have the same thing on our website, but it came from them. If you want to know the logic behind it I can ask them. If my memory doesn't fail me, I asked the same question ages ago and the response I got was that it accumulates calcium on the cell which then gets washed away when you clean it with acid, or it converts calcium to bigger particles which get filtered out by filter. But don't quote me on this it might be just my imagination. I will ask them this question.

WRT the rest - we really need to split the discussion into several topics and not jump between them

 

[Strannik]

Well I got a response from Autochlor, pretty much outlining what i said above. However they said that effect will be negligible, so they will remove it from FAQ. Thank you for reporting it!