What am I missing? Am I connected to main drain?

May 25, 2016
11
Phoenix/AZ
#1
I've never messed with the valves on this pool since move-in about a year ago. Pool came with an auto vac that was always connected. Trying to SLAM but not moving as fast as I had hoped. My Hayward Vac needs repair so I have taken it out. It occurred to me I may not be sucking from the main drain and just the skimmer. Sweeping algae and it goes no where. See photo above. Looks like I am just pulling from the skimmer. When I try to move at what I think would be half way my pump goes dry and I lose prime and filter PSI. What am I missing? Am I doing it wrong? Guidance please.

WP_20170502_18_09_28_Pro (2).jpg
 

Jimrahbe

Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
10,924
Bedford, TX
#2
Blake,

The top port on the your valve, the one that is currently shut off, should go to one of two places..

1. Your Main Drain
2. A vacuum port in the wall of your pool.. would most likely have a little flap or door..

What you can do to tell which is this...

Go to your skimmer and take out the basket.. Do you see two input pipes? See if they are both open or if one has a plug in it.
If one of the holes has a plug in it, then that would be a pretty good indication that the main drain is plumbed back to the equipment pad.
If both holes are open, then (on old pools) that would indicate the one pipe goes to the skimmer and the other to the Main Drain. With this system you need a diverter plate (Looks like a space ship) to make the main drain work.

When you move the valve "half way" make sure the word "off" never points to the pump... this will shut off all the water to the pump.

Try this and let us know what you find,

Thanks,

Jim R.
 
OP
OP
B
May 25, 2016
11
Phoenix/AZ
#3
Blake,

The top port on the your valve, the one that is currently shut off, should go to one of two places..

1. Your Main Drain
2. A vacuum port in the wall of your pool.. would most likely have a little flap or door..

What you can do to tell which is this...

Go to your skimmer and take out the basket.. Do you see two input pipes? See if they are both open or if one has a plug in it.
If one of the holes has a plug in it, then that would be a pretty good indication that the main drain is plumbed back to the equipment pad.
If both holes are open, then (on old pools) that would indicate the one pipe goes to the skimmer and the other to the Main Drain. With this system you need a diverter plate (Looks like a space ship) to make the main drain work.

When you move the valve "half way" make sure the word "off" never points to the pump... this will shut off all the water to the pump.

Try this and let us know what you find,

Thanks,

Jim R.
Hey Jim,

Yes, two input pipes and one is covered.

When I turned the handle towards the pump, "off" towards me, to which I thought would be the half way point, the pressure dropped.

Blake
 
OP
OP
B
May 25, 2016
11
Phoenix/AZ
#4
Follow up question: If the main drain has not been used in some time, could it just be that the pipe is empty and it's taking longer to prime? I turned the valve all the way and it stays dry. How long can I let the pump run "dry" to see if it needs primed?
 

Jimrahbe

Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
10,924
Bedford, TX
#5
Blake,

You don't want the pump to run dry for more than 30 seconds...

If I understand correctly, with the handle pointed up and the word "off" pointed down the pump will not prime.. if so, then we have two possibilities..

1. The main drain is plugged, either on purpose because it was leaking or plugged with debris.

2. Your pump has a suction side air leak and can't make enough vacuum to suck the water up to the pump.


My first step would be to take off the pump lid, inspect the gasket and lube it with "pool lube" and reinstall it. Then turn the pump on using only the skimmer and then switch to the 50/50 position. Use a garden hose and run water over the pump lid and intake pipes and see if the basket fills with water. If the pump runs ok when you use the garden hose, then you have a suction side air leak. The external water helps seal the leak.

To see if the main drain is plugged you could take the valve apart and stick a garden hose up into the top pipe and use a rag to prevent as much water coming down as possible. With the hose on full blast see if you see any indication of water coming out of the main drain...

Having said all that.. Main Drains are not really needed. I have two rent houses and neither of them have operational main drains, and the pools are just fine. If your plan is to sweep debris into the main drain in place of a vacuum, that will just not work. Main drains just do not have enough suction to make that plan work. In my opinion, if the Main Drain is working great.. if not, it might not be worth the effort to fix it compared to the limited benefits of having it working.

Your call...

Thanks,

Jim R.
 
OP
OP
B
May 25, 2016
11
Phoenix/AZ
#6
Blake,

You don't want the pump to run dry for more than 30 seconds...

If I understand correctly, with the handle pointed up and the word "off" pointed down the pump will not prime.. if so, then we have two possibilities..

1. The main drain is plugged, either on purpose because it was leaking or plugged with debris.

2. Your pump has a suction side air leak and can't make enough vacuum to suck the water up to the pump.


My first step would be to take off the pump lid, inspect the gasket and lube it with "pool lube" and reinstall it. Then turn the pump on using only the skimmer and then switch to the 50/50 position. Use a garden hose and run water over the pump lid and intake pipes and see if the basket fills with water. If the pump runs ok when you use the garden hose, then you have a suction side air leak. The external water helps seal the leak.

To see if the main drain is plugged you could take the valve apart and stick a garden hose up into the top pipe and use a rag to prevent as much water coming down as possible. With the hose on full blast see if you see any indication of water coming out of the main drain...

Having said all that.. Main Drains are not really needed. I have two rent houses and neither of them have operational main drains, and the pools are just fine. If your plan is to sweep debris into the main drain in place of a vacuum, that will just not work. Main drains just do not have enough suction to make that plan work. In my opinion, if the Main Drain is working great.. if not, it might not be worth the effort to fix it compared to the limited benefits of having it working.

Your call...

Thanks,

Jim R.

Jim - Great advice. Thank you!