Spa Drains to Pool After Check & 3-Way Valves Replaced

[DS]

I've learned much from this forum the last couple years but never had reason to post until now...

I have an inground pool/spa combo with elevated spa. Overnight, without the pump running, the spa drains to the pool water level. With the pump off for 36 hrs the spa water level never goes below the pool water level. Here's the actions taken without success: Replaced pressure side check valve flapper to spa. Replaced diverters in both pressure and suction side 3-way valves (Jandy Never-Lube). After replacements, configured valves so path from spa to pool is blocked on both pressure and suction side. Spa still drains to pool.

My hypothesis: There is an underground plumbing connection between the pool and spa that circumvents the equipment pad. Perhaps there is a pressure release valve that diverts the jet pump flow to the pool return line in the event the spa jets all become blocked?

Any help is much appreciated.

 

[JasonLion]

Welcome to TFP!

Problems like this one are almost always the check valve. Given you have ruled that out, the next most likely is that the spa leaks, but is getting refilled from the pool when the pump is off by the check valve.

There isn't normally a connection between the pool and spa that does not go through the equipment pad. The only exception is when you don't have a spillover there can be a hidden spillover pipe. But any such spillover pipe would have it's input at spa water height, not down at pool level.

The next step is probably to do a careful trace of all the plumbing and make sure there isn't some additional pipe connected to the spa on the equipment pad that you don't know about.

 

[DS]

Thanks. All plumbing at pad is accounted for and I even tried the food color test in the spa near the fill inlet and drain to at least try to determine source as pressure or suction side. No luck on that since apparently the leak is too slow to draw in the food color. I'm in CA in the event plumbing practices vary by state. My water bill has not spiked so I don't think water is going somewhere other than the pool.

 

[DS]

Also, I forgot to mention that there is a jet pump plumbed directly to the spa without a connection to the circulation system. I noticed that when the pump basket lid on the jet pump is removed a steady stream of water flows from the suction side and doesn't subside. Is this normal? I turned off the ball valve on the suction side of this pump and of course the flow stopped but the spa is still leaking. Does this issue provide any evidence or is it just coincidental?

 

[jblizzle]

Re: Spa Drains to Pool After Check & 3-Way Valves Replaced

If the jet pump is below water level, then the spa will drain when it is open ... thus the reason a ball valve was added.

Not sure what the issue is causing the spa to drain as you have checked everything. I would not be surprised that a leak would not be noticed on the water bill ... water is not as expensive as most people think.

Posted from my Droid with Tapatalk ... sorry if my response is short

 

[mas985]

Can you post a picture of your pad plumbing?

 

[DS]

Here are pics. I can post more if these don't help.

 

[mas985]

After replacements, configured valves so path from spa to pool is blocked on both pressure and suction side. Spa still drains to pool.

Exactly how did you have it configured? The return valve appears to be slightly on for the spa. If you shut that valve off completely (disable actuator), does the spa stop draining?

I know you have the check valve and that "should" stop the spa from draining but replacing the interior flapper doesn't always fix a check valve.

If the spa still drains with both 3-way valves in the off position, then one more thing to try:

Remove the SWG and the pump lid and leave them off. Assuming the valves are above pool level, this should break the siphon between the pool and spa. If the spa still drains, then it is probably a leak. If it doesn't, then there is still something wrong with the valves.

BTW, is the spa water level above the pad?

 

[DS]

Thanks so much for help with troubleshooting. This problem seems impossible.

After replacements, I closed both 3-way valves to the spa (fully blocking flow from/to the spa). This was done manually by removing the actuators and operating the valves manually. I left them in this position and didn't run the pump for 36 hrs and the spa still drains. However, the water level in the spa always holds at the same level as the pool. You're correct that the spa return valve is currently partially on. The pics represent normal operational position not the test position.

The spa water level is above both the pad and 3-way valves. The pool water level is equal to pad and slightly lower than the 3-way valves.

BTW, here is more info that may or may not be helpful...The circulation pump runs with air visible under the pump lid. If more suction is drawn from the main drains/skimmer than the suction side pool cleaner the air under the pump lid decreases. Also, when the pump turns off water squirts out from under the pump lid.

 

[mas985]

BTW, here is more info that may or may not be helpful...The circulation pump runs with air visible under the pump lid. If more suction is drawn from the main drains/skimmer than the suction side pool cleaner the air under the pump lid decreases. Also, when the pump turns off water squirts out from under the pump lid.

That is symptomatic of high suction when the cleaner is engaged but is probably not related to the spa issue.

I would try the experiment I suggested in my last post:

Remove the SWG and the pump lid and leave them off. Assuming the valves are above pool level, this should break the siphon between the pool and spa. If the spa still drains, then it is probably a leak. If it doesn't, then there is still something wrong with the valves.

This should pin point the issue. Also, if you see water flowing into the pump basket or out of the SWG port, that could point to a leaky valve. Just make sure the spa valve is in the off position for both.

 

[DS]

Well, another disappointing outcome following that experiment. Removed pump basket lid, removed SWCG cell, both 3-way valves closed to spa. No flow into the pump basket and no flow from SWCG port, but the spa still drains. Looks like I have an underground plumbing leak. No visible signs of leakage anywhere in the yard. Any suggestions on the next step?

 

[mas985]

If it is a leak, it seems suspicious that the spa level does not drop below the pool level. If you set the valves to spa only mode (close off the pool), does the spa still drop to pool level and stop?

Also, is there a way you can measure the exact pool level and does it go up slightly when the spa drains? If the spa is leaking into the pool and if the area of the pool to spa is on the order of 15:1, then if the spa drops 15", the pool should rise 1". If the pool does not rise at all, then it is definitely leaking.

If you confirm the leak, the first place I would look is at main drains. Drain the spa and remove the covers and see if there are any gaps between the pool and the pipes.

 

[DS]

I thought about the pool level test last night so I marked on the tile where the pool level is when the spa is full. This morning the pool level did not change but the spa drained. To confirm how much the pool should raise if the spa was draining into it I did the following: After the spa was filled and the auto-fill shut off, I intentionally drained the spa about 16" (normal overnight drop) and the pool level raised about 1". Unless I'm missing something, it appears this test confirms the water is not going to the pool. However, I'm still perplexed about why the spa level holds at pool level over an extended time...

 

[mas985]

That confirms that the water is going someplace other than the pool which would indicate a leak. It is possible that the leak just so happens to be at the same level as the pool. This would indicate a location that was fairly high in the plumbing and the only thing I can think of is the spa jet plumbing. It could even be the venturi air vent that fills with water when the jets are shut off.

Do you have a picture of the plumbing during the build (pre-gunite)?

Are any of the jets at about the same level as the pool?

Have you inspected around the jet area that penetrates the spa wall?

 

[DS]

So life happens and resulted in this project being temporarily shelved...

Here's what happened since the last post post:

I shut off the return flow to the spa until it actually stopped draining. Apparently, I did not cut the flow long enough before because this time the spa kept draining below the pool level and finally held at the bottom of the fill pipe. Next I plugged the fill line with a plumber's test plug and refilled the spa with a hose. The plug has been installed for weeks now and the spa has not drained (I've been maintaining the spa water separate from the pool to avoid algae, stains etc). Therefore, it seems clear that the leak exists in the underground fill pipe between the pump and the spa. Short of excavating my deck and landscaping, what methods are available to locate the leak?