Suction side leak - back pressure temp fix?

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C

cglubish

0
Apr 18, 2016
15
Kelowna, BC, Canada
Two pronged question here... I've followed all the usual steps to try and locate a suction side leak. No luck.
30 year old pool, 1 skimmer line to Hayward superpump to sand filter. I've had air bubbles on and off for years. Could never find a fix, so just ignored it.

Recently my heater started shutting off (low flow), because the pump is cavitating and never really getting a good flow going.

Exasperated, I called a pool company. He tried to find the leak and couldn't either. So then he suggested a stop gap fix of putting small eyes on the return jets. I have 2 return jets, and he put maybe 1/2 inch jets on (I had much larger one before). This made my filter pressure jump from 10psi to 19psi. The pump basket didn't fill right up, but did stop cavitating. The heater came on. And only water is coming from the jets (no more bubbles in the pool).

Is this a terrible idea? I under stand why the back pressure from restricting the jets would get pressure up in the heater and make it run. But I don't understand the physics behind why the back pressure he created stops air bubbles in the pool.

Any idea on what is going on? Is the back pressure going to damage my equipment or cause problems as stop gap fix? I assume the efficiency of the filtration process is not great. Could I damage the heater?

In the meantime I'll keep trying to find the air leak. But I've tried all the usual steps.... Frustrated.

Thanks!
 
By reducing the flow rate (water and air) through the pump, you have reduced the suction head at the pump.

You say you only have a skimmer line to the pump. No main drain?
 
mknauss said:
By reducing the flow rate (water and air) through the pump, you have reduced the suction head at the pump.

You say you only have a skimmer line to the pump. No main drain?
Click to expand...

My pool has a main drain that goes into the skimmer. Like the diagram attached. But I only have 1 pipe from the skimmer to the pump. It's all plumbed directly to the pump with no diverters or unions anywhere at the pump. Its old... 1980s.
 

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OK, that helps.

Have you tried plugging off the main drain port in the skimmer and see if that helps the air issue?
 
mknauss said:
I assume you have done all the tests shown in Suction Side Air Leaks - Trouble Free Pool
Click to expand...

Yeah, I can try again... I only have a small section of pipe coming out of the ground, hard plumbed into the pump. So there aren't a lot of options, but admittedly the connections are 30 years old. I couldn't find a leak, but maybe I should just redo the above ground plumbing...

I did replace the gasket in my pump lid a few days ago. It was old, but replacing it didn't help, despite the $25 the local store ripped me off for a gasket.
 
Be sure that gasket was well lubed.

Also check the drain ports on the suction side of the pump. The oring on them can dry out or crack.

Does your pool lose water with the pump off?
 
mknauss said:
Be sure that gasket was well lubed.

Also check the drain ports on the suction side of the pump. The oring on them can dry out or crack.

Does your pool lose water with the pump off?
Click to expand...
Not that I'm aware of... If its losing water its very small. This time of year I top it up occasionally, but in the spring when its cooler it seems stable. The pump is on an automatic timer so its off 1/2 the time.
 

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Have you ever used pucks in a floater and left it in the skimmer ? This will eat the piping directly under the skimmer and cause pin holes. Easy to check, put a plug in the skimmer hole that goes to the pump and take the cover of the basket so you can easily see the water level. Clean and dry everything in the area around the basket and pump / motor. When the water drops in the basket see if any on the surface around the pump / seal / motor shaft etc. If all is dry then the leak is in the ground. If you run your pump for a long time you will not see water lost as the suction is holding it in.
 
1Sammy said:
Have you ever used pucks in a floater and left it in the skimmer ? This will eat the piping directly under the skimmer and cause pin holes. Easy to check, put a plug in the skimmer hole that goes to the pump and take the cover of the basket so you can easily see the water level. Clean and dry everything in the area around the basket and pump / motor. When the water drops in the basket see if any on the surface around the pump / seal / motor shaft etc. If all is dry then the leak is in the ground. If you run your pump for a long time you will not see water lost as the suction is holding it in.
Click to expand...
I have never put pucks in the skimmer, but we only bought the house 4 years ago, so who knows about the other 26 years :)

So if I follow, you are suggesting I:
- turning off the pump
- plugging the line from skimmer to pump at the skimmer
- take lid off pump and watch water level. If it goes down, I have a leak underground.

Correct? This seems logical, why didn't I think of this. We are heading out of town for the weekend, but I'll try on Tuesday.

Thanks everyone who chimmed in so far! This forum is a life saver for me.
 
OK, I did the follow.
1) Turned off pump
2) plugged port from skimmer to pump at the skimmer (with the winter plug)
3) took lid off pump basket
4) I also, put the sand filter to waste and removed the pressure gauge relieving seal in the sand filter. I was thinking back pressure could create a slow siphon effect and throw off my results if I had a problem further downstream? My physics skills aren't good enough to know if that's possible, but figured it wouldn't hurt.
5) Waited 24 hours.

The water in the pump basket sadly drained a few inches. And I see no water in around the equipment. :(

So I guess that means for sure I have an underground leak? How would I locate it? I have 10 feet of concrete deck on the skimmer side, then 20 feet of grass, then a concrete slab where the pool equipment is. Either end involves concrete so it would be nice to narrow down where a leak is.

UGH. Is there any sort of stop gap fix for this to get me through the summer?
 
That's not what i was wishing on ya . The "usual" place is right under the skimmer in one of the fittings, SORRY.
You may be able to carefully cut the cement and break it away from the skimmer without damage to the skimmer. Last one i did i broke the skimmer as the cement was 8" thick as the diving board was next to it. You will need to dig down below the skimmer and an opening big enough to get in there and work under the skimmer. The leak of course could be any place and not at the skimmer but usually there is no reason to cause a break any other place UNLESS there is a coupling in the piping ?
A few things you can try. Add a water line to the piping under pressure and see if water comes to the surface. Add air and see if you see bubbles or can hear the air if you water down the area with your garden hose. You can turn the line into a loop line and use stop leak in a bucket with a small pump and run it for a few hours so the stop leak finds the hole and jams itself into it stopping the water lost. I have had mixed results with this. On a pressure line it works great as the build up is on the inside trying to get out even after the fix. But on a temp pressure line after you turn it back to your suction line it usually pulls out the juice and the hole is exposed again. I have never played with them but there are skimmers you can add over the side of the pool and run a pipe to your pump on the surface.
 
If I break the skimmer, I need to replace the vinyl liner right? We just replaced it a few years ago, so I really don't want to do that! If I cut into the concrete further away, then carefully dig towards the skimmer would that be ok, or would I need to cut concrete right at the skimmer? Whatever the case, I assume I'll be hiring someone since this seems above my pay grade. But I'd like to at least be able to know what to tell that person.

Too bad Widsor is quite far from Kelowna...
 
I just realized I can hear cavitating in the grass about half way back to the equipment. If I lay down and put my ear to the ground - don't ask how I figured this out :)

I don't think there are any couplings, but who knows. Maybe the previous owners broke the line digging or something. It is 30 years old, and we've only been here 4.

I'm not sure if the line I can hear is the suction or return line... But if it was suction, do you think hearing cavitating would indicate the leak is BEFORE that point (at the skimmer like you suggested). Or would it be impossible to tell...

Either way I'll dig up the grass there. That's an easy enough task to maybe get more intel and avoid the concrete.
 
hey hey hey, you might get lucky, fingers crossed fer ya... IF it comes to it there will be no need for a new liner if you break the skimmer. Yes you can leave as much cement around the skimmer as possible and "tunnel" over to it. Go at it from the direction were you think the piping is as you will need to cut it and re couple it after the fix if you have to go that far.
If i heard as you are hearing i would plug one end and put the garden hose on the other end with a no leak fitting that i would make up and see if the pressure from the hose would push water to the surface. In most cases if on open ground the water will come straight up. Of course if under the pad then it will have to rise and follow over to the edge to get out.
 

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