Check Valve for SWCG

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M

MarkHoop

Well-known member
Aug 16, 2022
133
Ontario, Canada
Pool Size
22000
Surface
Vinyl
Chlorine
Salt Water Generator
SWG Type
Zodiac LM3-24
I appreciate the feedback that I have been getting in the forums and have found them to be very useful (y).

I have been having HX corrosion issues since the installation of a new replacement heater in 2019 92 HX replacements)...another forum and another time...
I know that the manufacturer is claiming a few areas of concern
  1. Poor Pool Chemistry
  2. Lack of Check Valve between the Heater Outlet and the SWCG
  3. Lack of pool bonding
So for the sake of this forum lets simply focus on concern # 2. The manufacturer (Hayward) is actually coming for a site visit on Monday to discuss my situation and I would like to have an educated discussion with him as I do come from a scientific background.

Hayward still claims that for warranty purposes there needs to be a check valve between the Heater outlet and the SWCG. I know the easy answer is "they say it so ya gotta do it" and I get that but really, is this an actual scientifically based requirement?
  1. The concentration of Cl localized in the vicinity of the cell is fractionally higher than in the pool.
  2. The SWCG has a flow switch that stops Cl production on loss of flow
Is there any realistic opportunity here or am I simply banging my head against the wall due to the requirement?
 
MarkHoop said:
Hayward still claims that for warranty purposes there needs to be a check valve between the Heater outlet and the SWCG. I know the easy answer is "they say it so ya gotta do it" and I get that but really, is this an actual scientifically based requirement?
Click to expand...
No. It's a leftover from the 'all chlorinators need a check valve' rule that pre-dates SWGs. They were all tab feeders back in the day and the acid ate the heater when it leached out once the pump was off. (No flow) Ironically all it did was slow the damage down because the acid had to eat the CV first, and then eat the heater. Pentair (and others) have since removed the CV requirement but I haven't checked Haywards specs in a while.

*Edit* just checked and it looks like Hayward doesn't require it anymore per an aquapure 900 install manual

Screenshot_20231027_104951_OneDrive.jpg

You may have a hard time convincing a pro you don't need it, either way. My own 30+ year GC couldn't give me one reasonable argument why I needed it, once I shot down the acid, high chlorine and running/leaching while off concerns. True to form, he stuck to his guns with a 'because it says so'.
 
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What Newdude said.

Unfortunately most of this industry operates on the "because we've always done that" principle. Same reason all of their recommended chemistry levels have been virtually the same since the 1970s despite a mountain of evidence suggesting much better ways of doing things.
 
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dfwnoob said:
What Newdude said.

Unfortunately most of this industry operates on the "because we've always done that" principle. Same reason all of their recommended chemistry levels have been virtually the same since the 1970s despite a mountain of evidence suggesting much better ways of doing things.
Click to expand...
Plus a really easy way to get around warranty concerns...too bad really
 
MarkHoop said:
The SWCG has a flow switch that stops Cl production on loss of flow
Click to expand...
The SWCG has a flow switch that “Should” stop Cl production on loss of flow

There are cases where the cell continues to produce chlorine while the pump is off due to a faulty flow switch and because there is no way for the power to be removed when the pump is off.

I do not know if that happened in your case, but it is something to check.

If chlorine is produced while the pump is off, then the chlorine could damage the heat exchanger.
 
JamesW said:
I do not know if that happened in your case, but it is something to check.
Click to expand...
Good point and certainly one that I can test quite easily in the spring once I get the pool back up and running however the fact is that I run my pump and SWCG 24/7 (probably a discussion for another forum) so the only time there is no flow is when I backwash etc and I always switch off the SWCG and heater prior to stopping the pump.
 
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MarkHoop said:
Ya, unfortunately it is still in the heater manuals but a good "tid-bit" for the discussion
Click to expand...
I'd argue that the SWG manual is specific to SWGs, and not a blanket 'chlorinator' requirement like the heater manual. You've got nothing to lose by trying.

If you're the least bit handy you could install a CV in minutes before they get there.
 
Newdude said:
If you're the least bit handy you could install a CV in minutes before they get there.
Click to expand...
Handy is not the problem. Fortunately or otherwise, I have already been transparent about my issues with the manufacturer and really just need to understand where my issues around the new heater are coming from.
 
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If Hayward recommends it why not just use it...its not a big deal to have one, this way you don't have to worry about it if something does happen warranty wise and they don't cover it because no cv. Cv's are cheap I put it in my new build..
 
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