pump priming only 3/4 of the way

[SunnyD]

I'm really having a hell of a time this year with the pool opening. Meanwhile, my pool is turning into a pond.

I finally got my variable speed pump going (huge rookie mistake so please ignore my other post. I was running on 110V when the pump is 230. An electrician came in and sorted that out).

I then had to adjust all my plumbing as this pump connections are a little higher.

I got it running today praying that there would be no further complications. I was wrong. The pump is only priming about 3/4 of the way up. This seems to be good enough (temporarily) to circulate the water but it shuts off after a few minutes when the "auto prime" fails.

I used teflon lubricant and greased up the O-ring around the window of the pump. It appears to be in good shape. Water seems to be coming in from the skimmer at a good rate but it just doesn't create the full prime. There appears to be no leaks in the skimmer line. The water in the pool has stayed fairly constant.

I've cleared out the skimmer basket and the pump basket. Not sure what else I can do.

Any help/suggestions is appreciated!

[Teapot1]

Provided the water remains above the pumps intake its not necessary for it to be completely full. If as yours sounds the water is not constantly above the pump intake and lowers after a few minutes you loose prime and get the error message. In a nutshell you have a small air leak on the intake line so work your way through to locate it. O rings get flattened after a few years, I am a retired pro and even found flattened O rings on my setup last year so replace any or all if they are getting old, very low cost fix. Also not sure of the teflon idea, thick silicon grease stays in place, its why big manufacturers use it, if teflon worked I an sure they would change it.
Good hunting and let us know how you get on.

[SunnyD]

I replaced the O-rings, greased them up and I'm still getting about 3/4 the way up. The good news is that circulation is happening. I am able to bypass the auto-prime setting and the pump now defaults to timer mode after the prime fails. The water level stays consistently 3/4 up.

Here is what I think is happening and what I have heard from the store pros. I currently only have the skimmer line open. The main drain at the bottom of the pool has a leak and has been sealed off. Although this was not an issue for my previous pump, it was set up for 1 1/2" plumbing (what my pool currently has). My current pump is set up for 2" (internal) and 3" external plumbing. I've had to put in an adapter from 2" to 1 1/2". I'm assuming there just isn't enough water coming in. Thoughts?

What am I looking at for costs for repairs of the main drain? I'm assuming this is a huge undertaking otherwise the previous owners would not have just sealed it off.

The main problem I'm having now is that when I run my pool vacuum (not robot), I cannot get suction as the pump starts running dry pretty quick. I guess the only option is to buy a robotic cleaner or fix my old pump.

[Teapot1]

You dont need a main drain, they do very very little except leak. Dirt comes in from above the surface and that is the best place to remove it. What rpm are you running at? Yes 1.5" plumbing will put a restriction in the line so no point in trying to go above the maximum the skimmer can provide. I take it your pump is above the waterline from the sound of it which gives more issues with air getting in. Have you run on filter with a hose in the skimmer to force feed it so to speak?

[SunnyD]

The skimmer can go max of 3450 rpm (same as the max speed of my old one). That is what I am running at when I try to vacuum (and when priming). I have noticed that when it starts to return to normal speed (2000 rpm) the water level rises to the top but then slowly creeps back down after about an hour. I will try the force feed technique.

[Teapot1]

I have noticed that when it starts to return to normal speed (2000 rpm) the water level rises to the top but then slowly creeps back down after about an hour.

Ok thank you, you still have an air leak. Once you reduce the pump speed the suction is naturally reduced if air begins to creap back in its an air leak. As you have changed O rings then look very carefully at the pump filter lid for signs of a crack there or around the pump body.

[SunnyD]

OK, I'll give it another go today. Hopefully I just missed something