Seriously considering upping Horsepower...

[Cammer]

I've been fighting our suction cleaner (Hayward vac xl) for almost a year now and all but narrowed it down to horsepower. I'm not looking for the wisest answer (i.e., most efficient, cost-effective, or most durable) here as I am very busy with work, my wife is pregnant, and I just need the **** suction cleaner to work during the day to take the load off (I've been cleaning manually for a year now). Just hoping to ballpark whether increasing HP is: a)"absolutely retarded", or b) "not the best solution, but it should get your cleaner working and not destroy your equipment."

THE RUB: To get enough suction umph just to manually vacuum the pool, I open 1 skimmer and the dedicated suction line only. This lineup will successfully move the self-propelled suction line cleaner for about an hour before the wheels stop turning, but only if I prime the cleaner hose every time.

I know all the many many contributors potentially at play here (filters, plugs, leaks, etc. etc.). While my ME professional background really just makes me dangerous in the residential arena, hopefully it also means I'm competent enough to have ruled out all these minor contributors as real concerns. Or maybe I'm just a dumba**.


Pool specs:
Hayward 1.25 brake HP (SF = 1.25)
Basic 4-cartridge filter setup
20,000 gal
Hot Tub: 2 drains, 2 returns, 4 jets. Overflows into pool.
Pool: 2 drains, 2 skimmers, 4 returns, 1 dedicated suction cleaner line
*The pool is only 10 years old so pump station manifold/valving is excessive; the underground PVC is likely a mess. In my industry piping head loss is minimal almost no matter how congested. Hopefully one of you can tell me if it can be a more serious residential issue. If it is I would assume the solution is still HP...


THANKS IN ADVANCE GUYS, LOVE TFP.COM.

 

[mas985]

Before considering a new pump, there may be other things at work here.

THE RUB: To get enough suction umph just to manually vacuum the pool, I open 1 skimmer and the dedicated suction line only. This lineup will successfully move the self-propelled suction line cleaner for about an hour before the wheels stop turning, but only if I prime the cleaner hose every time.

Does the filter pressure change from when it is working to when it is not working?

Also, what happens when you are using only the cleaner line?

 

[jblizzle]

A 1.25 SFHP Tristar is not a small pump.
My 1HP Superflo is much smaller and runs a suction cleaner no problem, while still pulling water through a skimmer and running my solar panels.

Sounds like you should partial close the other skimmer to force more suction from the cleaner.

 

[Cammer]

Does the filter pressure change from when it is working to when it is not working?

Not noticeably.

Also, what happens when you are using only the cleaner line?

The pump starts to cavitate; 1 skimmer and 1 suction line are as much as I can neck down regularly and still know the pump is getting enough water with my back turned. I will say this though - with a spotless new filter set, spotless pump basket, and not a single leaf in the pool-side leaf strainer it could probably run on the suction line alone. Start to collect debris in any location though and it'll starve.

A 1.25 SFHP Tristar is not a small pump.
My 1HP Superflo is much smaller and runs a suction cleaner no problem, while still pulling water through a skimmer and running my solar panels.

Sounds like you should partial close the other skimmer to force more suction from the cleaner.

See above. I've tried it all folks, but don't get me wrong they're valid suggestions. The problem isn't the ideal world where the system (or in this case a partially-closed skimmer and leaf strainer) will remain debris-free for a week at a time. It's the usual world where this happens: I remove all pool debris manually so whatever falls from the trees hopefully the cleaner can handle, set the timer/prime the cleaner line/leave everything in the pool, and within a couple hours the cleaner has resumed its immobile position. Another example: I'd get everything working and the pump would shut down for the night, cleaner working at that time. Next morning it fires up and the cleaner never moves. In this case I would typically re-prime the hose and it will work for a while, but probably stop way before the end of the day; it's always stopped when I get home I know that.

Basically my current version of a suction cleaner is one that I have to re-prime every morning, adjust skimmer throttles to taste, watch the pump basket for excess air for 10 minutes, and then ask my pregnant wife to rinse/repeat at least once throughout the rest of the day - particularly if she starts to hear it grenading itself through the back window due to it having actually caught a handful of leaves.

Yes there are tweaks and tricks and adjustments I can make (and have been making) every day, but the simple fact is it just seems like I'm pulling a fifth-wheel with a 1/2 ton. Yes I can throw it in low gear, floor the throttle, turn off the A/C, keep the radiator just below boiling, and yes probably make it over the hill most of the time. But wouldn't it seem more appropriate just to buck up and spend the extra $ for a diesel?

 

[jblizzle]

Sounds like maybe you are sucking in air if you reduce to a single suction line? Do you see air? How do you know it is cavitating?

The cleaner hose should not fill with air when the pump shuts off ... mine doesn't.

You have a suction leak somewhere ... and a new pump is not likely to fix that.

Again, your pump is already WAY bigger that the ones that Mark and I have ...

 

[mas985]

I really don't think that increasing the pump THP is going to do you any good. Higher THP pumps basically have higher head curves and can produce higher pressure but the suction capabilities (NPSH) don't change as much. Increasing the pump size will likely cause even more air to enter the pump basket (BTW that is not cavitation) and force you to redirect flow away from the cleaner even more than you are now.

I run my suction cleaner with a 1/2 HP pump ( 1 THP) so smaller than yours without a problem. In fact, I can run on low speed but I do need to put all the suction on the cleaner line when running on low speed.

I think there is a problem with your setup somewhere that is causing the problem. My suspicion is with the cleaner line, hose or head. Have you taken everything apart to make sure there is no debris stuck in the hose or cleaner head?

A few more questions, when the cleaner is running correctly, what is the filter pressure?

When you are not using the cleaner at all and have flow from every other suction port, what is the filter pressure?

 

[stebs]

If it's cavitating, it's not getting enough water... More horsepower won't fix that and might even make the problem worse

 

[Cammer]

I'll get some numbers when I get back in town after the weekend - thanks for the help everyone.