Pool is losing water! HELP!

[CrockerDave]

Howdy!

First let me say that I'm a semi-rookie when it comes to pools. I bought my house 1 yr ago & it came with a pool. I've got the water chemistry aspect of things down pretty good, but I'm not the best at troubleshooting mechanical issues...which brings me here

The issue i'm having is this: when my pump kicks on, the water level in my pool DRASTICALLY drops (like 1" in a little over an hour). The water level only drops when the pump is turned on. This just started happening this past Sunday (Aug 2nd). It's so bad that i'm having to decrease the time I run my pump to ~2 hours per day, and then fill the pool back up with the water hose every day (not looking forward to next month's water bill). From reading some other threads on here, i'm thinking I may have an underground pipe leak on the suction-side (i really hope not). Another possibility I thought of is that maybe my multi-port valve is broken and the water is going out my waste/backwash line. Something else I noticed is that when my Polaris is OFF, there is a small stream of water leaking from what appears to be the impeller area of the Polaris booster pump. When the Polaris booster pump is ON, the leak stops.

Some info about my pool & pump/filter arrangement. Pool was built in 1997, it's 15,000 gal, gunite IG. I have 3 lines that go to my pump (each line has its own valve...like they type of valve you'd see on a garden hose spigot); #1 a "main drain" in the deep end, #2 a line from the skimmer baskets, and #3 a "vacuum line" which comes from a small plastic pipe that protrudes about 2-3" into the side of the pool & it's ~6-8" below the waterline (I hook my vacuum hose up to this). Unfortunately I don't know the make, model, or capacity of my sand filter, pump, & booster pump for the Polaris 380. I do know that both pumps are single speed pumps. I can take pics of all this when I get home from work today. And I think the previous owner left me a folder with information about the pool...I'll find that; hopefully it has specs in it on the equipment.

ANY help, suggestions, or comments are greatly appreciated!! Thank you in advance!!

 

[OldPoolBoy2]

This seems to be more of a supply side leak rather than on the suction side. Where does your filter waste water go. Is it plumbed somewhere or do you use a hose? If it was plumbed then the spider gasket on your multi port valve could be suspect (or the valve itself). What is the pressure gauge reading now when running and what was its normal running pressure before this occurred?

 

[CrockerDave]

Another piece of info I forgot to mention; when the pump is on, water comes out of the jets like normal (just wanted to add that).

This seems to be more of a supply side leak rather than on the suction side. Where does your filter waste water go. Is it plumbed somewhere or do you use a hose? If it was plumbed then the spider gasket on your multi port valve could be suspect (or the valve itself). What is the pressure gauge reading now when running and what was its normal running pressure before this occurred?

My filter waste water goes through a PVC pipe to the city sewer connection. The pressure gauge is reading 10 psi now. Before it was around 15-20 psi (it would read around 15 psi after backwashing the filter.
I think today after work i'm gonna open up the multi port valve & inspect it. Also, what is a spider gasket?

Thanks for your help!

 

[brysclar]

I do not have a multi-port valve, so I can't speak to that. I can tell you I had a similar leak situation in my pool. My water level was dropping a couple inches a day, only when the pump was on. I couldn't find anything. I called a leak detection company. They pressure tested the lines and found cracks in my return jets. Short term solution: they epoxied the cracks. Long term solution: replace the returns. It cost $275 for the service call. They didn't charge anything to seal the cracks, and they gave me a written estimate to replace the jets.

 

[CrockerDave]

I do not have a multi-port valve, so I can't speak to that. I can tell you I had a similar leak situation in my pool. My water level was dropping a couple inches a day, only when the pump was on. I couldn't find anything. I called a leak detection company. They pressure tested the lines and found cracks in my return jets. Short term solution: they epoxied the cracks. Long term solution: replace the returns. It cost $275 for the service call. They didn't charge anything to seal the cracks, and they gave me a written estimate to replace the jets.

Interesting...I could see that definitely being a possibility. About how old was your pool when this happened?
Thanks!

 

[duraleigh]

You should be able to eliminate some things pretty easily.

1. It is not a suction side leak. That would suck in air, not spew water.

2. can you disconnect backwash at some point to observe if water is going out the backwash when you are in filter position?

3. Are you sure it only leaks pump running?

 

[CrockerDave]

You should be able to eliminate some things pretty easily.

1. It is not a suction side leak. That would suck in air, not spew water.

2. can you disconnect backwash at some point to observe if water is going out the backwash when you are in filter position?

3. Are you sure it only leaks pump running?

To answer your questions...
2. The only way I can disconnect the backwash is to break apart one of the connections where the PVC pipe goes to a PVC fitting. I could do this if I absolutely had to, but I think it would be tricky.
3. Yes, i'm sure it only leaks when the pump is running. After re-filling the pool back to the proper level & turning the pump off, I've checked every couple of hours (and I checked it the next day), and the water level stays the same

Thanks for all the help guys! When I get home I'm going to attempt to ID the brand & model of my multi-port valve & sand filter and also open up the multi-port valve & inspect the spider gasket & the valve itself. I'll report back on what I find. I've got my fingers crossed that it's just the spider gasket! I googled it, and found a youtube video on how to replace them...looks pretty straightforward.

 

[duraleigh]

Well, it would be good luck if the spider gasket was the fix and I think it's quite possible. Keeping our fingers crossed. Let us know.

 

[brysclar]

Interesting...I could see that definitely being a possibility. About how old was your pool when this happened?
Thanks!

I honestly don't know. The house was built in 1984, and I moved in about 3 months ago. I would estimate the pool is about 20 years old.

 

[CrockerDave]

I wanted to post back an update: PROBLEM SOLVED!! My spider gasket was fried. My multi-port valve is a Praher 1.5" side-mount SM 10-3, 26-1173 (I've learned that they were purchased by Pentair at some point). The whole Praher/Pentair thing made googling the correct part number for the spider gasket a bit tricky, but I found it online & my local Leslie's had it in stock for about the same price ($19). I think I read somewhere online that older Pentair multi-port valves were actually manufactured by Praher, but sold under the Pentair name (or vice-versa, I can't remember).

Anywho, I installed the new spider gasket yesterday using the Blue RTV to "glue" it in, and I applied some waterproof grease on the top of the gasket. Spider gasket part number is 271104 (some places online call it a "diverter gasket"). Hopefully this will be of some help to someone. Also, I kept seeing online that there were 2" and 1.5" models of multi-port valves and I wasn't sure where to measure on mine to determine this. However, when I went into Leslie's, I had the part number for the 2" & the 1.5". I asked the guy @ Leslie's "How do I know which size I have?" He showed me the top of a 2" multi-port & it was much bigger (diameter) than mine...very obvious when you see them side by side.

Pics of what my old spider gasket looked like when I removed the multi-port:


Here's the waterproof grease I used on the top of the spider gasket (purchased @ Lowes):


Here's the Blue RTV I used under the gasket to "glue" it down (Purchased @ Ace Hardware store):

 

[brysclar]

Wow! Fried is right! Nice job.

Sent from my LG-D850 using Tapatalk

 

[CrockerDave]

Thanks! I'm definitely relieved it was only a gasket. I wasn't looking forward to busting apart PVC connections...

Thank you for all the help guys!!

Oh, and one more thing I wanted to share...I learned that it's a best practice to always turn the multi-port valve 1 direction (i.e. don't turn it clockwise one day & then counter-clockwise the next day). I had NO IDEA about this and never even thought about it being "bad" for the spider gasket.