Confusing Pump Issues Unexplained

[mmcwhorter]

I am seeing two very odd things with my pump-fliter system this year...and I am at a loss after some small degree of troubleshooting it.

Everything "works" fine, the system operates, FC is produced by the IC-40, the system filters, etc... BUT::::::::

A- after a long Off Time, pump start-up (prime) time to get water flowing is very long, like 3 minutes after a long time off....If I cycle the pump on/off/on/off with a ten-second dwell time, the water flow is pretty much immediate. So, no loss of prime over a short duration.
B- when the pump is turned off, there is a violent back pressure from the strainer basket that causes most all of the leaves in the wall skimmer to be ejected over the Weir door and into the pool, and most times this back pressure pops the skimmer basket up and sideways, rendering it useless next time the pump turns on. Sometimes, it interferes with the proper operation of the Weir door....holding it closed or vertical.

As to A: I bought a new gasket for the pump skimmer basket, Hayward Super Pump 2HP. What's very odd is when I run the pump for 15-30 minutes, then shut it off....then I open the lid on the pump skimmer basket: I hear a vacuum break when I pull the cover. So I am thinking it's not a leak on the inlet pipe or valve causing the extended duration to prime the the water flow when the pump restarts.

As to B: I am at a loss. This seems to happen went the filter whether or not the filter has been backwashed or not. Last night it did it with the pressure at 16 psi, I backwashed and it was down to 14-15. So, not a seriously clogged filter. I had to leave for a few days today and I asked my wife to keep an eye on it. When I get back I am thinking of trying this test in Recirculate mode.

ANY IDEAS?????

Confused in So MD.

 

[mas985]

Those symptoms are consistent with a suction side air leak. Air fills up the filter and is under compression when the pump is on. Once the pump shuts off, all that pressure is released through the plumbing and most of it goes backwards towards the skimmer.

A suction side air leak makes it more difficult to prime a pump as well.

Also, a pump should never drain of water when it is shut off. Yours sounds like it is draining.

All this issues could be due to a gasket leak in the pump lid and/or drain plugs. First, inspect all of the gaskets for cracks and if you find them, replace the the gaskets. If they look ok, then use a good pool lube to lube the gaskets for a better seal. If that doesn't work, you need to look at other o-rings/seals from unions and valves.

Also, make sure the pool level is halfway up the skimmer mouth.

 

[mmcwhorter]

I agree. About 3 weeks ago I replaced the pump skimmer gasket...and greased it. The old one was not cracked but it appeared to be vertically compressed. I was hoping that was it.

Then, I tightened the drain plugs, but did not replace last years teflon tape. Maybe I should back them out and wrap with tape.

Hard to tell how much water is in the basket after 3-4 hours pump off. I'll check soon.

Can the lid warp? And when I open the pump strainer basket cover with the screw wheels, I hear what sounds like a vacuum "sucking sound....That indicates to me that there that there is no leak.

I have three Jandy Diverter Valves in front of the pump. I'll look at that next. They are those stupid "Never Lube" type....maybe I need to remove and replace them with the right kind of screw (I have them already).

 

[Jimrahbe]

Those symptoms are consistent with a suction side air leak. Air fills up the filter and is under compression when the pump is on. Once the pump shuts off, all that pressure is released through the plumbing and most of it goes backwards towards the skimmer.

+1 to the above advice...

It sounds like a pretty good sized air leak to me..

I'd try to run using just the skimmer, and see what happens, then just the main drain, then the vac line etc..

Thanks,

Jim R.

 

[mmcwhorter]

I am opening ONLY two wall skimmers for suction from the pool. The deep-end suction is closed ....and also so is the Spa suction.

In fact, in the current situation it's darn near impossible to get the thing started if I switch the valves to only deep-end suction. The leak reduces the pump head drastically.

It's a good idea to play with the suction valves...I'm biz traveling but will do it Friday upon return.

I'll Teflon tape the drain plugs. And make sure the pump skimmer basket cover is as tight as I can make it.

Are there any ingenious ways to check air leaks on a permanent threaded PVC connection?

BTW: My returns are all open...four returns back into the spa and that water flows over the waterfall, the sidewall return that used to be used for old school vac, the deep end has a return, and two small returns by the steps at the shallow end.

 

[Jimrahbe]

Mark,

Returns don't really have air leaks, unless they also have water leaks when the pump is running.. If water drips out, with the pump running, then air will leak in when the pump is off... This often result in the pump or filter draining back into the pool when the pump is off..

Show us several pics of your equipment pad and maybe one of us can come up with some ideas..

One way to test for a suction side air leak, is to run water from a garden hose over the pump and valves... In theory, it you watch the water under the pump lid, when the water finds the air leak, it will get sucked in and the bubble under the pump lid will go away.

Thanks,

Jim R.

 

[mmcwhorter]

Yep, I was already thinking about posting pics...and for sure there are always bubbles up against the top of the lid when it's running.

It's time for me to open up the diverters and apply some grease on the suction side anyway. At startup, I did the return side only, ran out of time that day and never finished the suction side. Sounds like a proactive thing to do is go ahead and order the cover gaskets for each diverter valve now. I have three on each side.

Thanks, see you again on Friday when I return home.

 

[mmcwhorter]

And the only leak on the supply side is out of one of the Never Lube" ports. It's pretty slow. I already bought the parts to remove them all (6)....and replace with the proper threaded screw.

 

[mas985]

I am opening ONLY two wall skimmers for suction from the pool. The deep-end suction is closed ....and also so is the Spa suction.

In fact, in the current situation it's darn near impossible to get the thing started if I switch the valves to only deep-end suction. The leak reduces the pump head drastically.

That is because when you shut off suction ports, the pressure in the pump basket and suction side plumbing drops creating even more suction which tends to draw in more air from any existing air leak.

I'll Teflon tape the drain plugs. And make sure the pump skimmer basket cover is as tight as I can make it.

Drain plugs should not need Teflon tape. They should have gaskets that provide the seal (along with pool lube). If they don't have gaskets they may be missing.

Are there any ingenious ways to check air leaks on a permanent threaded PVC connection?

I have used pool lube on threaded connections to help find leaks. A suction side leak will draw in the pool lube and temporarily seal the leak and even in some cases for smaller leaks it may seal it for a longer period of time.

BTW: My returns are all open...four returns back into the spa and that water flows over the waterfall, the sidewall return that used to be used for old school vac, the deep end has a return, and two small returns by the steps at the shallow end.

Increasing the water paths on the return side, reduces head loss and increases flow rate. However, on the suction side, increased flow rate will also lower pressure in the suction side plumbing increasing any existing air leaks. Also, if this is done to an extreme, it can actually cause cavitation in the pump. To minimize problems with the pump suction side, it is always best to make sure the suction head loss never exceeds the return head loss.

 

[mmcwhorter]

Looks like the problem is solved and thanks to all for your comments and support. I went through a logical troubleshooting process and found Valve 2 missing the large "cover seal O ring"....See pic, valve 1 closest to the pump, valve 3 farthest, and valve 2 in the middle. Took apart all three, replaced all o-rings....greased them up well. I have no idea how the missing o-ring became missing. I probably re-greased these valves 3-4 years ago. Maybe I did not replace it...but the problem only got bad recently....so that's a bit of a mystery. Anyway, all new o-rings inside, greased up and working great. No bubbles. Pump takes about 3-4 seconds to get up to full speed after 1 hour or more off. No back pressure, etc...All good here. Thanks again.