Rush of Chlorine Odor When Solar Turns On

[ClemonsPool]

See if the problem continues when there are no tabs in the feeder.

I would not leave tabs in the feeder with no water flow.

Once the tabs get wet, they continue to dissolve and create a very dangerous, corrosive and toxic mixture of acidic water and chlorinated gasses that will migrate through the system and destroy anything they can get to.

A continuous flow of water keeps the concentration of chlorine in the feeder down to a reasonable amount.

I should mention this. If the pool temp reaches set point, then the solar turns off. The pool filter still continues to run, causing water to continue to flow through the tablet feeder. If the pool temp cools off a bit and the system thinks it could heat with the sun, then the solar kicks on and I’ll get a rush of the chloramine odor. Does that make sense? I think I’m running it correctly.

 

[JoyfulNoise]

Trichlor dissolves very rapidly at temperatures above 92F. This is one reason why you never use trichlor in a hot tub, the high water temps will dissolve the tablets too rapidly causing a very sharp increase in FC and drop in pH.

My guess would be that a rush of very hot water from the panels is running through the tab feeder when the solar valve opens and you are getting a big burst of chlorine from that.

I agree with @JamesW suggestion - pull the tabs out of the feeder, put them in a chemical floater in the pool and run the solar heating. I bet the odor stops.

 

[JamesW]

There's a bunch of air that gets introduced when the panels come on.

That could be causing any accumulated concentrated liquid and/or chlorinated gasses to get discharged into the returns.

The key is to prevent buildup of chlorine in the feeder by limiting the number of tabs and to make sure that you always have some flow through the feeder.

 

[mas985]

I’m trying to figure out how to do this given my existing setup. I’m wondering if I could somehow run some pvc pipe from the drain at the low end of the system on the roof, along the gutter, then down the side of the house. I would try to tap into one of the pool lines that runs in the ground along the side of the house after going into a backfield preventer to allow water to only flow down the drain, not up. Sounds crazy, I know.

Much of the water should siphon out as is. That is the reason you are hearing a rush of air into the VRV. But to help with the rest, you can use a small 1/4"-5/16" tube connected to the lowest point near the drain spigot. Because the siphon tube is thinner, air has a more difficult time traveling up the tube so it should siphon nearly all remaining the water even though it travels up and over the roof peak. However, the connection point is critical. It cannot be where air enters the plumbing due to the solar draining. So connect it to the pad plumbing at a point that is below the pool water level or anywhere where the plumbing does not lose prime because of the solar panels (i.e. before filter check valve). A check valve in the tubing is not really necessary because when solar is running, the amount of flow through the tube is insignificant.

One more thing, if you move the VRV to the supply side far end (picture right), then most of the water should get siphoned out of the panels without any modification.

 

[ClemonsPool]

Much of the water should siphon out as is. That is the reason you are hearing a rush of air into the VRV. But to help with the rest, you can use a small 1/4"-5/16" tube connected to the lowest point near the drain spigot. Because the siphon tube is thinner, air has a more difficult time traveling up the tube so it should siphon nearly all remaining the water even though it travels up and over the roof peak. However, the connection point is critical. It cannot be where air enters the plumbing due to the solar draining. So connect it to the pad plumbing at a point that is below the pool water level or anywhere where the plumbing does not lose prime because of the solar panels (i.e. before filter check valve). A check valve in the tubing is not really necessary because when solar is running, the amount of flow through the tube is insignificant.

One more thing, if you move the VRV to the supply side far end (picture right), then most of the water should get siphoned out of the panels without any modification.

Thanks for this information. I’m going to check into this option. I wonder how long it would take to drain 7 panels.

 

[mas985]

If you move the VRV, there should be only a small amount of water left. You can time the drain by temporarily connecting the tubing to the spigot and seeing how long it takes to drain.

 

[sktn77a]

Is that a Polaris pump plumbed in after the chlorinator? (I hope not..................)

 

[ClemonsPool]

Is that a Polaris pump plumbed in after the chlorinator? (I hope not..................)

It is. The pool company plumbed it that way. You’ve got me a bit nervous, but perhaps your concern could explain why I’ve already gone through one in less than 4 years. The second one makes a god awful sound every time it starts, like there may be air in the line, then mellows out shortly thereafter.

 

[JamesW]

The chlorine from the tab feeder probably ruined the seal and water ruined the front bearing.