How to set up and run my VS pump?

[davelinde]

My (first ever) pool has had water for a week now. I'm learning as I go...
We arranged our own subs to build it so the startup and learning has been a bit of a patchwork between the various guys testing their bit, giving advice and leaving. I understand all the valves and what it all does... but I'm collecting minor questions as I go. Here's my wonderment today...

1. Air? During one orientation I was told I don't want air trapped in the top of my filter since (for obvious reasons) filter efficiency is reduced. Purging air seems easy. However each time I check there seems to be air collecting in the top of the filter. Also, at the lower pump speeds I can't purge it. I'm thinking maybe the site glass over the pump basket could be leaking? Am I right that once primed the suction side should not accumulate air if operating properly?

2. Gauges? The plumber left a pressure gauge and vacuum gauge and later someone told me to put them on the pump for final inspection. So I did. Just passed inspection. Do people normally leave the gauges on the pump, or does it make more sense to put the plugs back and only have a gauge on the filter (which seems to read very low mostly)?

3. Speed? As noted, at lower speeds I cannot purge air from the filter... but assuming I stop the air at the source - can I use very low circulating speeds? How low? For my water features I assume I just pick the speed/valve setting that makes them work nicely... and it's subjective. But for filtration and cleaner (robot) settings, how should I pick a speed? How do I pick a duration for my timers?

If there's a search or sticky I should be reading... let me know - I assume these are very basic questions for people who know what they are doing (which is currently NOT me).

 

[JasonLion]

The will often be some air in the pump strainer basket, especially at lower speeds, but there should not be any air in the filter. If the filter is filling with air you have a leak on the suction side (including possibly at that gauge you mentioned).

Once you pass inspection, you should remove the gauge etc from the pump and install the drain plug(s).

You want to use a pump speed around 1000 RPM for general pool filtering, as long as that is fast enough for your skimmers to work effectively. If required by the skimmers, or a SWG, you may need to go higher, though many get it to work at 1000 RPM. Higher speeds are generally required for water features, as you said adjust till they look right.

 

[davelinde]

COOL! seems I'm on the right track more or less then. I'd been playing with speeds between 900 and 1100 based on nothing in particular. I just noticed the plugs have o-rings and those gauges were sealed with pipe dope. I think the o-ring should do better - so the gauges are coming out now. I'll reseat the pump strainer too... I've pulled it a few times because the basket is still picking up a few pebbles and concrete debris that must have dropped into the lines when we opened the main drains or skimmer.

 

[davelinde]

"The will often be some air in the pump strainer basket, especially at lower speeds"

The plumber was by and that's what he said too... though neither one of us had an idea why. He just said that with the variable speed pumps that can run at low speed they tend to collect a little air. How?

I've replaced the gauges with plugs and run the pump a little faster now and it is much better - but I still collect a little air in the filter and even here/there in the returns (when I crank the pump up high I will see some air purge from the return jets). hmmm...

 

[jblizzle]

My 2-speed gets a fair amount of air at the top of the pump when I run on low as well ... no bubbles in the pool or air in the filter I don't think.

If I throw it on high speed, and purge the bubble from the pump out of the filter, I see no more air in the pump/filter/pool.

Only guess is the extra suction on higher speeds creates a better seal on the pump lid. On low speed, the lid is not pulled as much and a little air squeaks by. At this point I have been running on low for months and it does not appear that the bubble is getting bigger.

Sounds like you are getting more air than this though ....

 

[JasonLion]

The pressure inside the pump strainer basket (on the suction side of the pump) is lower then the ambient air pressure. Because of that some gas will come out of solution and form bubbles in the strainer basket. At higher speeds the pump is efficient at clearing out the majority of the gas that does accumulate, but at lower speeds it is not nearly as good at doing so, so more gas accumulates.

It sounds like you have a fairly slow suction side air leak. A good tactic for pinpointing the location of the leak depends on being able to see air bubbles entering the pump strainer basket. If you can see bubble entering, try running a garden hose over each plumbing connection on the suction side in turn. If you run water over the connection that is leaking, air bubbles will stop entering the pump strainer basket.