Is it OK for the SWG to be on without water flow?

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D

davelinde

0
Sep 18, 2012
391
Lake Nona, Florida
Split from original topic. Please ask questions in your own topic, rather than hijacking someone else's topic. JasonLion

OK... tagging one more SWCG install question onto this thread. Mine is plumbed after the filter but only feeds the main returns, there is a valve in front of it to send water to 4 other water features. I remember the plumber said he thought it was good to be able to run them without chlorinating too.

One question though... the SWG is wired to come on with the pump and I have no other automated control over it. Is it OK for the SWG to be on without water flow? It has an indicator and sense low (no) flow so I am guessing it is smart enough not to harm itself?
 
While the flow switch is a safety interlock and it's supposed to work, however there is a thread going on where one didn't and caused an explosion as best we can determine. There was some other stuff going on, but if the flow switch had shut the swg down the event wouldn't have occured.

Having said that, I'd want an additional layer of protection than just the built-in flow switch. Will your automation system tell the swg not to run when the water features are on? I would think you should be able to program that in.
 
Flow sensors are not as reliable as one might wish, so it is recommended practice to make sure that the SWG is never turned on when the pump is off, typically by only powering up the SWG when the pump as power. If you have an automation system that integrates with your SWG, it does this same thing in a slightly different way, insuring the SWG is never active when the pump is off.

It is common to put the SWG on the pool return line and not on other "feature" lines, though this is not normally required. The most common case is to not have the SWG feed the spa. Running a SWG at it's pool setting will be way too much chlorine for the spa. (Unless you have an automation system that compensates for this, which most do). Feeding just chlorinated water to a waterfall or fountain is wasteful as chlorine can evaporate out while the water is in the air. (Though this isn't really a major problem because you don't lose all that much chlorine unless it is a mister or other extremely small drop fountain.)
 
Bama Rambler said:
Will your automation system tell the swg not to run when the water features are on? I would think you should be able to program that in.
Click to expand...

The SWG is hardwired onto the pump relay at the moment, but I do think it might be possible to move it to it's own relay and program it, though once it is a separate on/off item it could be manually turned on alone. My other option would be to always flow water through the SWG when any feature is on. I think the implication of that would be that I'd need to set the waterfall valve to partially open instead of programming the pump speed. I need to play with it. If I drop the pump speed so the waterfall makes a pleasing trickle the SWG flow sensor trips but if it run the pump higher with the waterfall valve full open there's too much water flowing on the waterfall.

Hmmm... maybe I'm over complicating this.
 
davelinde said:
there is a valve in front of it to send water to 4 other water features. I remember the plumber said he thought it was good to be able to run them without chlorinating too.
That is not good! That needs to be replumbed! I would rather have the chlorinator running into the water features rather than power the iC40 without water flow.

One question though... the SWG is wired to come on with the pump and I have no other automated control over it. Is it OK for the SWG to be on without water flow?
Absolutely not.
It has an indicator and sense low (no) flow so I am guessing it is smart enough not to harm itself?
Click to expand...
I would not trust the flow switch on an iC40 to be your only safety.

The other thread that Bama is referring to had two problems that "Budman" had no idea was happening, The pool builder was responsible for one, crossing the power source for two iC40's, and a defect, a stuck flow switch, was responsible for the other. Either one could do the same damage but having both just made sure that it would happen.
 
As I navigate my way through the setup here I am better understanding my valves and the intent. I plan to remove the actuator from the valve that splits the return from the water features and leave it set sending water both directions to insure flow over the SWCG all the time. I will use the extra actuator for the solar system (when we install it later). For the time being the actuator is in the center position and switched "off" so it can't move.

Based on the clear advice here I think I will be careful not to run the SWCG without flow and I think keeping the valve fixed will accomplish that.
 
What you should do is ask the plumber if he could come back and replumb it correctly, to take water for the water feature after the cell. You can tell him that you should not have to pay him for this because it is a safety issue, and more importantly (to him) is that, the way it is plumbed right now is a liability for him! If you had an event that involved the cell, i.e. a hydrogen explosion, that he would be liable for damages. Im sure that once you informed him of that, he would be happy to make it right.
 
Pool Clown said:
What you should do is ask the plumber if he could come back... tell him that you should not have to pay him for this because it is a safety issue
Click to expand...

Well... actually he's been paid already because he passed all the inspections. Ironically he will be here tomorrow to quote the addition of solar so I'll talk to him about it. So if he cuts out the valve and puts in a tee it's safe? If a flow detector fails you think I could go after his license? If so, why isn't it code?
 
A tee would give you no control over the water feature, and i doubt any water would go to it. Path of least resistance.

When i said you should not have to pay, i was referring to the corrective plumbing he needs to do, that he may want to charge you for.

It isn't(violating) code because the manufacturer has provided a flow switch (not that there is a code to enforce with respect to the operation of SWCG's to begin with). The fact that i wouldn't trust the flow switch is just my opinion/advice.
 
If you run the SWCG without water flow, the process of electrolysis (or lack thereof) will produce hydrogen gases which will build up and cause the cell to explode. While the flow sensor is installed to turn the cell off without water flow (technically, it's installed to turn the cell on with proper water flow), it should not be relied upon to control the cell and will fall under "improper use of product" which deems it a non-warranty issue. For these reasons, the SWCG is installed on the same relay as the pump.
 

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"A tee would give you no control over the water feature, and i doubt any water would go to it. Path of least resistance."

The water features are running off a cascade of tees now and they all flow fine, each water feature is on its own cascaded valve. The plumber was here and said this is how he plumbs all features, especially spas which will tend to over chlorinate if they are not split off. We are going to move the actuator from controlling the return/water features to controlling the new solar when it's done. This will make the valve splitting the features from the returns pretty much a service valve only.

When I set up the flow rates for all the different configs I'll make sure I always get flow on the SWCG, so the flow switch will be a backup only.
 
If the water features work with all ports open, great! What you can do is adjust the valve actuator so it stops before it closes off the port going to the cell. So when you run the water feature you can have some of the water still going to the cell. Your pool guy may know how to adjust the cams. You just need to be careful not to close it off too much. I can't stress enough that the cell needs flow to keep the gas that gets produced flowing to the pool in the event that the flow switch fails/sticks and not allowed to accumulate in the piping.
 
Pool Clown said:
If the water features work with all ports open, great! What you can do is adjust the valve actuator so it stops before it closes off the port going to the cell. So when you run the water feature you can have some of the water still going to the cell. Your pool guy may know how to adjust the cams. You just need to be careful not to close it off too much. I can't stress enough that the cell needs flow to keep the gas that gets produced flowing to the pool in the event that the flow switch fails/sticks and not allowed to accumulate in the piping.
Click to expand...

Actually, my setup is a bit more complex but as I've had some time to fiddle with it I think it's all good... Hopefully the ascii schematic below is understandable. The first tee of the return cascade is between the SWCG/main returns and the water features. If I remove the actuator there and manually leave it split 50/50 I will always have flow to the SWCG (for pump speeds above about 800 rpm). In the default condition all the other valves are running at 100% through with nothing diverted until I get to the Bubbler/Sunshelf valve which I will default to run the returns on the sun shelf.

If I cam the waterfall to divert at about 80% through, 20% to the waterfall I get a nice trickle down the rocks while still getting good flow to the SWCG. I think I'll keep the therapy jets cammed at 100% through or 100% to the jets (which shuts off the bubbler/shelf returns if I use the therapy jets). So in all cases I have flow to the SWCG. One of the pool contractors showed me how to cam the actuator and it is easy. Now all I need to figure out is how to program the iAqualink and I'll be set up.

Bubbler ---- X ---- Sun shelf returns
. |
. |
. X ---- Therapy jets
. |
. |
. X ---- Waterfall
. |
. |
. X---- SWG ---- Main Returns
. |
. |
. VS Pump
. (Suction side)
. |
. |
. Skimmer ---- X
. |
. |
Main Drains ---- X ---- Vacuum
 
Pool Clown said:
Is that the way it has always been plumbed? If so, there is no problem here. All the water features appear to be downstream of the cell. Maybe you can post a picture to confirm this but, i think you are ok.
Click to expand...

This is the original plumbing config. Maybe my diagram is not clear. The first X is a T valve in cascade with more T's. The first T can send 100% of the water to the features and 0% to the SWCG/main return, or it can split the water 50/50 between the SWCG and the features, or it can send 100% to the SWCG and 0% to the features. If I just leave the valve in the 50/50 position all is good I'm thinking.

THANKS! for the advice, help... I'd hate to explode something due to ignorance. (Actually, I'd hate to explode something for any reason)
 
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