Compatibility of heaters with SWG

[Titanium]

I am considering whether to convert my pool to a saltwater pool. The recent acquisition of a AquaLogic PS4 control system ended up coming with a SWG cell.

I downloaded some equipment manuals for new Jandy (Laars) gas-fired pool/spa heaters. The manuals for the Jandy Lite2 and another Jandy line both stated that the heater was for freshwater pools only and not for saltwater pools. The acceptable chemistry for both heaters stated that the TDS would need to be below 2000 ppm. http://www.jandy-downloads.com/pdfs/H0248900D.pdf

So I decided to call Jandy technical support in order to find out which heater line would be acceptable for a saltwater pool, since the manuals I was looking at indicated that these two particular lines were not suitable. The Jandy tech guy said that when the manuals said "saltwater" that this meant pools with a salt content of less than 6000 ppm. He said that Jandy considers pools with salt content of less than 6000 ppm as "fresh". I then asked him about the requirement to keep TDS below 2000 ppm and how this would be possible with the recommended salt level of 3000 ppm. He went away for awhile and came back with the answer that in order to determine the "true" TDS levels for purposes of following the water chemistry of the manual, that one should first test the TDS levels, then subtract out the salt levels, and then that would be the TDS levels used to determine whether one was meeting the 2000 ppm limit or not.

I must admit that, as an engineer, that this conversation did not leave me with a warm and fuzzy feeling. I think that I would need the verbal assurances given in the above paragraph to be documented in writing somehow. Especially that the "How to Order" page on the Jandy website for the heaters mentions several different metallurgies available for the heat exchanger tubes. Oddly, I can not find any reference at any internet sites that sell Jandy heaters that there is even an option to buy different metals for the heat exchangers.

[web]http://www.jandy-downloads.com/pdfs/Heater_ordering.pdf[/web]

I then asked whether my existing 23 year old Laars heater would be suitable if I converted my pool to a salt water regime. He said that my old heaters heat exchangers would have no problems in a 3000 ppm salt pool.

Maybe I should be hitting this question from the other direction. What material is suitable for heat exchangers and headers in a 3000 ppm salt water pool?

Titanium

 

[Poolsean]

He's correct. If you test for TDS and do a separate test for salinity, the difference it the TDS that they are looking to maintain below 2000 ppm.
Your heater should be fine with a salt system, as long as you don't exceed 6000 ppm and maintain your chlorine levels at about 3 ppm.
High salt and high chlorine levels can cause corrosion to your heat exchanger.
With a 23 year heater, your heat exchanger may be in a worn condition already, so it would be good to perform a visual inspection first.

What type of heater material is ok with salt sytems? They all are, within reasonable salt and chlorine levels, and proper water balance maintained.
Titanium Heat Exchangers, as in heat pumps, are virtually chemically impervious to attack. There are certain coatings that can be had with gas heaters too.

Hope this helps,

 

[Titanium]

Poolsean,

Thanks for your reply.

OK, so maybe the Jandy guy wasnt' being as flaky as I thought.

I just wish that the Jandy manual had clear definitions of "fresh" and "saltwater" and how to determine the "true TDS". It seems like these would be questions that every heater owner would need to know in order to run a 3000 ppm saltwater pool.

Why do you think that Jandy offered some many options for the heat exchangers and headers? :?

My CYA is presently off the charts at 160 ppm or so, and I plan to rectify that this winter by partial refill and drain cycles. So I can live with a chlorine level as low as 3 ppm with the recommended CYA level of 50-80?

And you have an excellent suggestion of visually checking the condition of my heat exchangers. This is on the To Do list. Also, the pool inspector from last year had mentioned that we needed a new stainless steel burner tray, so I will be looking a little closer at this component also. My heater input versus output BTU's indicate an efficiency of 70%. It looks like the newer heaters are more on the order of 82%-84% effcient. This old Teledyne Laars (now Jandy) appears to be made like a tank. I am always suspicious that the new units would not be constructed as rugged.

Thanks again for your help.

Titanium

 

[EskimoPie]

I had this exact concern on my recent build. I'm using a Sta-Rite 400k BTU gas heater and have a SWCG. Reading the Sta-Rite manual it had similar statements not to use it in a salt water pool, only fresh water. I called Sta-Rite and asked them if this heater was approved for use in a SWCG equipped pool and they said absolutely. It does leave me with a little uneasiness since if I have a heater failure down the road they have the legal option to deny a warranty since the manual says 'no saltwater' and I have no proof of otherwise.

 

[Poolsean]

AutoPilot has been selling salt chlorine generators in South Florida for years and have worked fine with gas heaters using cupric-nickle heat exchangers (the standard material used). You will see some corrosion effects with extremely high chlorine levels maintained, and excessive salinity levels.
The fact is you're more likely to see the damage as a result of improper water chemistry than you are from 3000 ppm salt.