Main drain flow

[brucebc]

I have a small pool with one inlet just below waterline, one outlet just below waterline, and one main drain. Only one pipe to and from the pump/filter area. My main drain sump has two holes, one with a plug in it. Don't know if this is for pressure relief or what. No valves. No skimmer niche.

The no-niche skimmer kept getting stuck and making my pump suck air, so I took it out and bought a Betta 2 solar skimbot instead. It's a very well designed machine.

I've read the arguments against main drain, but in my case, without a niche skimmer, I'd prefer to have just the main drain. But when I plugged the vacuum port, my pump bogged down (perhaps to 30% of prior flow). And empties the basket if run on high speed. I think my main drain line is clogged somewhere. I took the pump off and used a drain bladder back up to the pool, but nothing came out except a few bubbles.

Next I'll try going in the main drain, with a camera, a plunger, a wet dry vac, etc. Seeking ideas: anything else I should try?

 

[ajw22]

Show us pics of your equipment pad and pool so we can better visualize your situation.

What HP is your Superflo pump?

What size pipes do you have?

I think your pump may be too large for the capacity of your suction system.

 

[brucebc]

I think Superflo VS is up to 1.5HP. I don't know what the piping under ground is, but the inlet and outlet are 1.5", and the last few feet to the equipment is 2". Below is a pic of some of the equipment. I don't think overpowering is the problem, I think it's a semi-clog, because I can get 10PSI at the filter and 60GPM at max pump speed with the vacuum port open. Yet only 2-3PSI and 5GPM with upper port closed (so only main drain open). Have not yet tried the reverse to be sure, but will soon. So it's flowing, water is coming out the inlet, but relatively little.

 

[ajw22]

What is the route your main drain is plumbed to the pump?

 

[brucebc]

What is the route your main drain is plumbed to the pump?

I'm not sure what you mean? If you mean, what does the pipe run look like underground, I have no idea, I just bought this house. I know the main drain and vacuum/skim port are connected, because there's only one pipe from the pool to the pump, but that's all I know so far.

 

[ajw22]

Good luck in your hunt. I don’t think you have a problem.

Main drains are usually not designed and connected to be high suction for safety reasons. And if you do not have a VGBA compliant main drain you should not be increasing the suction on the main drain.

Safety Drains VGBA - Further Reading

www.troublefreepool.com

Main drains are designed to be secondary to the skimmer and are there so that if the water level gets low the pump will not run dry.

Until you know how the main drain line connects with the suction line you will be groping in the dark.

 

[brucebc]

Good luck in your hunt. I don’t think you have a problem.

Main drains are usually not designed and connected to be high suction for safety reasons. And if you do not have a VGBA compliant main drain you should not be increasing the suction on the main drain.

Safety Drains VGBA - Further Reading

www.troublefreepool.com

Main drains are designed to be secondary to the skimmer and are there so that if the water level gets low the pump will not run dry.

Until you know how the main drain line connects with the suction line you will be groping in the dark.

This pool has no skimmer. The vacuum port is a heck of a lot more dangerous than the bottom drain. The bottom drain cover is VGB compliant. Groping in the dark continues this afternoon!