Bad motor --> cavitation damage = useless wet end?

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Re: SUCCESS!!! Thanks for all the help in multiple threads!!! :)

Seems like your pump is too big for the plumbing. Sure you can change the plumbing but maybe simpler just take the motor and impeller down 1/2 HP. Pool pumps offer different flows to the amount of head. Replacing an entire pump can cause these issues.
 
Side conversation about motor running backwards was moved HERE. jblizzle

Well, while all of this talk of a reversed motor is interesting.... I think it is a Red Herring. Two motors, both going bad, points at something wrong OTHER than the motor. How about the contacts in the time clocks and/or both "speeds" being energized at one time? How about a wonky breaker? Intermittent wiring (wire nuts and/or corrosion)?
 
I just saw this.


Red face SUCCESS!!! Thanks for all the help in multiple threads!!! :)

Hey all,

I finished up the re-install of a new motor and a re-plumb late last night, and everything seems to still be in working order this morning. Ran it on high for a couple hours last night, then low over night. I was comfortable taking slow steps with the motor, checking amperage each time (consistently getting 5.5A and 1.8A on the two speeds.) I was able to finally use the gauges installed in my pump to check my head, and got some interesting results. More on that later, maybe a separate thread.

The only potential problem is that the diverter valve replumb doesn't seem to like working in the manner it works. I get a ton of air in the pump basket when I'm only sucking from a single 1.5" line. I still suspect a problem with the tubing, but it could just be that I need 2" pipe all around the pool (will do that next time we change the liner, probably.)
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MitchRyan912 I am glad as I am sure your are that you got to the bottom of this. I have been following your several threads on this topic from . It would be helpful if you went back to each thread and gave a final result for future reference of others. (Or maybe a moderator could combine these similar threads into one.

Bill
 
jblizzle said:
I merged a couple threads. Please stop making new ones. jblizzle

There should be no problem running this pump on 1.5" PVC lines.
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What about 1.5" flex PVC that's 30 years old? What about if said flex pipe was installed before 30 arbor vitae trees were planted over top of where the pipes are located?

image.jpg

lefty51 said:
Do you get the air on low speed or only on high
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There is a lot of air on low, which I believe is to be expected? There's still a bit of air bubbles left that aren't going to the volute and into the filter.
 
How should I go about checking them? I'm not so sure about leaks as I am that the roots grew in such a way that they constricted or crushed the pipes.

Instead of running parallel to the pool down this grassy area, the pipes swoop out towards the fence line of our property, which is right behind these trees. I guess that helps eliminate 90's and 45's to the pad the way they did it (it's a tight corner behind the shed), but I think I'll be digging a trench next time we get a chance to redo things with the pool.
 
Will be building one of these contraptions later this week. Is air pressure testing preferable? I can borrow an air compressor from my work for a day or two, so using air pressure is something I could definitely do. Would I skip the 1.5"x0.75"x1.5" T and just add a hole for an air hose, or would I hook the air hose into an adapter and put that adapter into the 0.75" part of the T?

BTW, so far so good with the pump! It's been running just fine for the past few days. I've got it on high from 7-9am, low during the day, back on high from 9-11pm, and off over night. I just calculated that with this new motor (.75 hi/.125 lo HP) that it's saving me over 80% of the electricity that running the old 1 HP pump 24/7! While we might not see any saving for quite a while (we're on a "budget plan" with the utility), this whole mess of blowing up the old motor and adding a timer will definitely save us money in the long run. If not for the 1 HP motor blowing up, I'm certain that I'd have never messed with adding a timer or putting a 2-speed motor in.

Thanks again for the help everyone!!!
 
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Here's what I used for air pressure test: add some misc. pvc adapters and you're set...
The only problem with air testing is pressure change due to temp change.
If the pipes are mostly underground, they will likely not be exposed to much of a temp variance, after 10 mins or so for the outdoor air to acclimate to underground piping conditions.
If you use nitrogen, the test is much more accurate.


Winters Instruments PETG Series 2 in. Gas Test Pressure Gauge with Test Valve Adapts to 3/4 in. FNPT and Range of 0-15 psi/kPa-PETG201 - The Home Depot

Fernco 2 in. EPDM Rubber Shielded Coupling-P3000-22 - The Home Depot
Note: you don't need much pressure to test. 5-10 psig is more than enough. A rubber coupler will not handle high pressure very well.

SLIME 2060-A Hand Floor Bicycle Pump,21 In. - Walmart.com

BTW, did you ever test current on the 12 volts you were getting from the low speed terminal? Was is just ghost voltage?
 
OK, so that's just a pressure gauge on an adapter that allows you to hook up a bike tire pump on one side, and a connection for the 3/4" hose on the pipe contraption I'm going to build? Would I not need the pressure gauge on the top of the pipe then (on the PVC end cap)?

All my pipes are buried underground until they reach the pump, where the ends have been dug up. Seeing what I'm seeing here is what's causing me concern. I'll post a pic in a few minutes, of the tree roots showing near where I dig up the flex pipes.

What's the 2" rubber coupler for, and where does that go?

I have a portable backup battery charger that's got a tire pump built into it. Would that work, or might that be too much pressure? It can pump enough air to fill up my car tires.

I had to return the ammeter to my father-in-law the other day, but I'm pretty sure it was just a ghost voltage. Every current test I did seemed to be well within the normal range (both high and low speeds), so I think everything is OK.
 
Just checking but did you already try lubing the pump lid gasket and drain plugs? The most common of air leaks.
 
...and failure. The new motor didn't last 30 days. I'm at a complete and total loss as to what's going on with my pool now. :(

The motor runs (but sounds bad) on both speeds, but only runs for a minute tops before shutting off. It smells of smoke (burning type smell) as it runs.
 
I need to ask something to humor my wife: The original pump was a 1 HP pump with a SF of 1.25. The new motor (same wet end) is a 3/4 HP motor with a SF of 1.6. Should I have changed the impeller size from a 1 HP impeller down to a 3/4 HP impeller, or is the THP rating what needs to match up from impeller to impeller?
 
It is the THP that matters. But clearly something is not right. You are positive you are getting the correct voltage at the motor? You might want to check the impeller size.
 
The pump is an SMF-110, which is noted as a 1 HP motor in their literature (see below), but the motor that came with it was a 1.25 SF motor, so the THP was 1.25. I replaced the original motor (that died mid-summer) of the SMF-110 with a 2-speed motor with roughly the same THP, a 3/4 HP top speed with a SF of 1.6.

SMF
 

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