Experiences with inexpensive XtremePower / Vivohome pool pumps from Amazon/eBay?

[gkw4815]

Currently all of our pool equipment is working nicely except that the 2 hp PacFab Challenger pump that operates our waterfalls is noisy and has been ever since we purchased our house ~a year ago. The pool was built in 1996 and I assume that this pump is original. Thankfully our equipment is on the far side of our garage and not too audible from the pool area, but out of respect for our neighbors we'd love to quiet the pump down.

The pool company that installed our new heater and filter last year looked at the pump and said that the bearings are likely going out. For what it's worth - the sound is more of a gnashing sound vs the shrill whining sound I'd associate with bad bearings, but I'm no expert on the subject. Other than the noise the pump works fine and doesn't leak. On average we might run the waterfalls for ~1 hour per week.

This company gave us a quote to replace our 1.5 hp Sta-Rite circulation pump with a 2.7 hp Jandy VS pump and move the Sta-Rite (which is still whisper-quiet) over to the waterfalls. Interestingly, the tech who looked at the equipment thought that the 1.5 hp wouldn't adequately replace the existing 2 hp waterfall pump, but his boss insisted that the 1.5 hp would work just fine.

We're considering this option (and definitely wouldn't mind saving some $ on electricity with the VS pump), but given that we spent a fortune last year on the heater and filter, we are also looking at cheaper alternatives. I'm comfortable with electrical and PVC work and am thinking of replacing the waterfall pump myself and just holding off on a VS main pump install for the time being.

Which brings me to my questions:
-Any experience with the 2 hp XtremePower / Vivohome pool pumps that sell on Amazon / eBay for ~$200-250? Reviews seem to be generally positive except for a few early failures and some complaints that the pumps aren't strong enough. Hoping that in my limited-use application I could get a reasonable lifespan out of the pump.
-I've heard the PacFab Challenger referred to as a "high pressure" pump particularly well-suited to running waterfalls / water features. Can a "standard" pool pump adequately replace this, or would I expect a major reduction in flow/performance?
-Does anyone know if these generic pumps (or any other inexpensive pumps) are a direct replacement for the PacFab Challenger that wouldn't require modifying the existing PVC piping? I could handle modifying the piping if needed, but don't want to overlook a simpler option if there's one out there.

Thanks in advance!

 

[ajw22]

Waterfall pumps are a low head high flow application.

WaterFall | Jandy

The WaterFall series configures the Stealth pump platform to deliver high-flow, low-head performance in the quietest way possible.

www.jandy.com

WaterFall Specialty Pumps - TradeGrade

Lets see what @mas985 says.

 

[mas985]

Do you have actual model numbers for each of the existing pumps? HP ratings are not enough to know for sure what you have. The challenger might actually be the High Flow vs the High Head. The former is more of a waterfall pump.

Post a link to the pumps you are considering.

Another option would be to just replace the motor of the waterfall pump.

Also, can you describe the waterfall plumbing? Pipe sizes, run lengths, suction port type, etc. Also, describe the type of waterfall (there are many different types) and perhaps a picture of it might help.

 

[gkw4815]

Thanks for everyone's replies!

I did some more experimenting with the pump today and have made some observations:
-I'm no longer convinced that the motor bearings are going out, despite what our pool guy said. As mentioned earlier, the sound is more of a "rock tumbler" gnashing vs a whirring or whining. I also noticed that the motor and pump are fairly quiet while starting up/priming, it's only during steady operation that it makes a racket.
-I've attached pictures of our pool, equipment pad, and the three valves that control flow to the waterfalls. The left valve controls the pair of small waterfalls on either side of the spa, the center and right valves control the two large waterfalls on the right side of the pool. I'm not sure where the waterfall intake is, but I think it's one of the three drains at the deep end of the pool.
-If I choke back one or more of the waterfall valves, the "rock tumbler" noise is dramatically reduced! The pump isn't as quiet as our main circulation pump, but it's no longer distractingly loud. After experimenting with various combinations of valve settings, I've found that opening the two large waterfall valves ~halfway and choking back the third valve nearly all the way results in little noise and (maybe) better flow from the main waterfalls than what I experienced previously. Less air in the pump basket as well.

Taken all together - would this suggest that I was experiencing cavitation, rather than bad bearings? If so, would this suggest that our waterfall pump is oversized? The pump is apparently ~26 years old, so it's unlikely that it was too badly mis-designed (BTW I believe earlier remarks that it is a high flow pump, not high head pump, are correct. I'll post a picture of the model # later). Would choking back the waterfall valves as I've done be a reasonable way to hopefully get a few more years out of the pump? (keeping in mind that we don't use the waterfalls that much)

Thanks in advance!

 

[mknauss]

The rock crusher sounds implies it is cavitating. So creating back pressure on the pressure side will effectively reduce the rate and thus eliminate the cavitation.

 

[mas985]

It looks like there are three return lines and only one suction line. This can create very high suction head loss and lead to cavitation if all three lines are 100% open. Keeping each of the valves partially closed should prevent that from happening.

 

[gkw4815]

Update - I replaced the filter basket (worn out and handle was missing, allowing to basket to float up in the chamber) and the filter basket lid gasket. No more air in the filter basket, no more cavitation sounds, pump is running better than ever!

Unfortunately the cavitation starts again if I try to run all four waterfalls at once - I need to leave the waterfalls near the spa shut off (and the main waterfalls choked back somewhat) to keep the pump happy. Would this suggest that:

1) The system simply doesn't have enough suction capacity to run all of the waterfalls at once, no matter what I do with the pump?

OR

2) If I downsized to a high-flow low-head pump like the Jandy Waterfall pump, I could run all of the waterfalls properly?

I'm happy enough with the system's performance that I'll leave everything alone for now, but would like to be prepared with an action plan when/if my old Challenger pump does fail someday.

 

[mas985]

1) yes - however, even if the suction pipe was infinity large, the problem might still exist because there is not enough return head loss. If a pump operates close to run out, far right side of head curve, it will also cavitate.

2) no - total flow rate would be less

The problem is the imbalance in head loss between suction and return. Return head loss should always be more than the suction side. Plus total head loss needs to be larger than the minimum of the pump's head loss curve.