pump slowly losing prime

[sjpoolowner]

Thank you again. I did a little experiment and tried to block skimmer side flow using the thing and ran the pump at 3000rpm. Then to my surprise I actually noticed water flowing into the skimmer pipe. I examined the plastic thing (what is it called?) after turning off the pump and found that the flap that I initially closed the hole was actually moved. I guess it does that when the pump is running really fast and main drain only can't provide enough flow? So it looks like when I primed the pump, I actually opened both the skimmer and the main drain.

So assuming that no air is sucked into the skimmer, what are my options now? Try to run the pump at full speed regularly? Replace the o-ring? Add lube to the pump lid area?

Would appreciate any help. This issue is really bugging me now.

[mas985]

So I take it that even running at 3000 RPM did not remove all the air?

I removed the plastic flaps from my skimmer a long time ago. For efficiency reasons, you really don't want to restrict flow in anyway and leave everything wide open. Plus restrictions on the suction side can cause air leaks as well as other issues.

But besides the pump lid, there are several other areas where air can get sucked into the plumbing; pump drain plugs, valves, and worst case, a cracked pipe. Any construction over the buried pipes recently? One trick to find leaks in plumbing is to spray shaving cream on the various valve/plug connections and see if anything gets sucked in. If you eliminate everthing on the pad, then look again because a lot of times you may think there is no leak when in fact there is. Hopefully it isn't in underground. Air leaks can be one of the hardest things to find. Water leaks not so hard.

[sjpoolowner]

Yes. What you see in the pic was as best as I could do at that moment. I might have done better if I keep repeating it. Unless I did something wrong.

What I did to prime was: stop the pump, open the air valve of the filter, run the pump at high speed (up to 3000 rpm) until water coming out of the filter air valve, close the filter valve and wait a little. I didn't open the lid since there was water in the basket except for one time to clean up the o-ring and lid surfaces. And I had to try this sequence multiple times to achieve that.

Anything to try for the lid?

I'll try the shaving cream method. I do hope it isn't in underground!

Thanks a lot.

[BigDave]

sj,
Did you happen to notice if your returns had strong flow when you were running the pump at high speed after it was primed?

[mas985]

Besides Bigdaves question above, what was the filter pressure at 3000 RPM after priming?

Also, it is somewhat counter productive to open the filter bleeder valve when the pump is off since this allows air into the filter which then displaces the water actually making it harder to prime. You are much better off opening the valve only after the pump is turned on to prevent draining of the filter.

Silicone pool lube is the best stuff to use on the pump lid and drain plugs.

[PoolDoc]

Silicone pool lube is the best stuff to use on the pump lid and drain plugs.

I am *not* disagreeing; when you need a lube on a pool pump, that's what you need. And, it can help stop leaks. (or even find them!, when goop-ed onto the inlet fitting to pipe fitting contact area)

But, gosh, I hate that stuff.

It's pretty much a last resort for me. I'll replace seals, O-rings, lids, fittings, etc. before I'll get that stuff out. It is the stickiest, hardest to get off goop I've ever dealt with, except maybe epoxy paint. But epoxy paint eventually dries, and that stuff never does. If a tube of that gets loose in a tool box . . . plan on HOURS of fun cleaning up.

And, when you put it on a pump O-ring, you can pretty much guarantee that every bit of dirt, sand, grit, leaves or twigs that get within 3" of the ring will be magnetically drawn to the goo, and then instantly and permanently attached. (Of course, that's more of an issue in the East, than on the West Coast or Southwest.)

Once there, it's almost impossible to get dirt off. Forget about a paper towel -- they aren't strong enough. You have to use a rag . . . which is then ruined for any further use. Especially, hand wiping.

Did I mention that I hate that stuff?

[mas985]

Ben,

I am not sure we are talking about the same thing. This is the stuff I use and for me at least, it doesn't get sticky nor does it dry up so you can easily wipe it off with a rag if you ever need to:

http://www.lesliespool.com/Home/Pump...ies/68926.html

BTW, this is exactly the same stuff as plumber's silicone grease which I have used as well with the same results.

[PoolDoc]

I've used the "Jacks Magic" stuff that's been around in the pool industry for years. It's great for sticking a large O-ring -- that would otherwise jump out -- in place, say on a Challenger pump. But it's also as I said.

I have used the Rainbow chlorinator silicone, and it's not like that. The Leslie's stuff could be more like the Rainbow stuff, in which case it wouldn't be so good on a Pentair Challenger pump back O-ring . . . but it would be much better everywhere else.

[sjpoolowner]

Thank you all. My answers to your questions are:

1. The flow seems strong when I run it at high speed. As mentioned earlier, that's after 95% priming.

2. The filter pressure is 27 psi at 3000 rpm, 29 at 3100 and 31 at 3200. I think the pressure was 10-11 psi when running at 2000 rpm. I have Sta-rite system 2 PLM 200 cartridge filter (200 sq ft). Haven't cleaned it for about 2 years since I didn't notice significant increase in filter pressure yet. I plan to do it before opening the pool this year.

3. I tried to open the filter air valve after turning on the pump. Not much difference observed. I see intermittent clusters of small bubbles coming out of the returns but they seemed to stop after a while.

I decided to run the pump at 3000 rpm for hours and see if that makes any difference. I'll update this afternoon.

Based on the fact that water level in the pump basket is lowering very slowly, it looks to me that pump not being fully primed is a different issue than the air leak? Or are they actually same? Should I suspect clogged suction line as well?

Thanks again. I really appreciate your help.

[sjpoolowner]

Actually, I kept watching the returns after running the pump at 3000 rpm for 15-20 minutes and noticed the bubbles kept coming out. They are very tiny bubbles and not "shot" out of the return. Rather they just float along the wall where the return is. Very intermittent, sometimes I have to wait 10-30 seconds to see another group of bubbles. I also noticed that they come out of only one return, whose water flow is stronger than the other return's.

Does this mean the air trapped in the pump basket is slowly being pushed out and thus a good thing? Or does this merely indicate air is slowly entering into the system? I tried to look into the pump basket to see any bubbles coming from the suction but it was difficult to see inside (the lid not as transparent as I would want it to be and also air pockets made it harder).

I think I am okay even if the pump doesn't fully prime as long as it stays that way and I don't need to re-prime the pump. But I'll have to fix any air leaks.

Thanks a lot.