Water pressure booster pump won't start consistently - do you rebuild the bearings?

[dpb]

On 8/14/2018 7:58 PM, Gil wrote: ...

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trader already beat you to it... :)

[Gil]

Just wanted to point out, your math is a little off. Should be 65 x 2.3 which indicates a head of 149.5 feet. ( 1 foot of head produces .43 lbs of pressure.)

[Arlen Holder]

It's pretty clear now that the two outside (black) wires are the two 120VAC phases coming in, and the two inside (blue) wires are the two phases going into the motor.

Yeah. 118VAC RMS on each to the green ground when the motor is running and

236VAC RMS to each other when the motor is running, as measured on my DMM.

Interestingly, I originally checked each black incoming phase to the steel water pipe expecting that to be grounded - but it wasn't all that good as the voltage was around 20 volts so I used the green ground instead.

Something weird happened, but wasn't repeatable, but it could be the pressure built up.

a. I turned the circuit breaker back on b. The motor ran c. I checked all the voltages (which were as expected) d. With a stick I pulled the contacts open e. Obviously the motor stopped f. But when I let go with the stick, I expected the contact to slam back g. They didn't. They stayed open. Huh? h. I pushed them closed, expecting them to stay closed i. They didn't. They opened when I let go of pressure. j. Huh?

What I'm "thinking" (but need to test) is that there is an electromagnet which keeps the contacts closed (something kept them closed in step (b) above. Maybe it was just the lack of pressure though, and not an electromagnet.

Contacts pushed open: Contacts pushed closed: contacts closed

Anyway, I'll have to test again as there seems to be three states: a. Contacts automatically closed and they stay closed b. Contacts pushed open and they stay open c. Contacts pushed closed but they won't stay closed

It could depend on the pressure though... but "something" keeps the contacts closed which didn't do it once I opened them manually.

[Gil]

If as you say, they are only approx. 10 feet, then that is only going to create approx. 4.3 pounds of pressure to the inlet of the booster pump. You have a duff gauge and/or a plugged line between the pressure switch and the pump output.

[Arlen Holder]

I'm not sure what you're saying there as your edits got garbled (it happens to all of us), but I do AGREE that buying a motor as a spare is a good idea given that (a) repair costs more than a motor, and (b) with the pump there is no water pressure.

Plus, it's always handy to have an extra 1HP motor around to use as a disk sander or whatever.

The problem of course is matching what is needed to fit nicely. a. 1 HP (SF 1.4) is a given, as is 115/230VAC & 3450 RPM & Frame 56C. b. The "jet pump" part seems to be in the "cast iron" head.

BTW, I realized that the model number is actually SHORTER than I posted, because they mix the model and serial number together, it seems.

The model number seems to be: 5KC39QN

I'm still confused about this "jet pump" part of the spec though.

I need to learn more about this "jet pump" part because I think if I just buy a motor, it's not a "jet pump motor" but just a "motor". The "jet pump" part seems to be in that cast-iron head - which would likely stay since it has all the pipes connected to it.

Can I just buy "any old" booster-pump motor that fits those basic specs? Like, for example, this one?

[Arlen Holder]

First hit explains the model number a bit.

5KC39QN It might even be just 5KC39 for the model.

5 = motor KCP = permanent split capacitor (only mine is a KC & not KCP)

39 = 48 frame motor (notice that doesn't agree with the nameplate 56C) All 48 frame motors have a 1/2" diameter shaft and a 5-1/2" diameter body.

[trader_4]

Uh oh, I expect you'll be hearing from Fretwell about calling them phases, that's supposed to be verboten. Saying two phases is pure heresy. Where wer e you when we were having that long electrical engineering discussion about what 240/120 service really is in the other thread?

[trader_4]

I said if it is the pump, you should probably be looking for a whole pump, not a motor. DPB said it doesn't have to be a jet pump either, which I agree with.

[dpb]

On 8/14/2018 8:02 PM, Arlen Holder wrote: ...

Of course it depends on the pressure...looks like it ran just long enough to get above the cut-in point. Remember, it doesn't pull in until it gets _below_ the setpoint; soon as it's above it'll stay open until it gets below again even if it hasn't gotten to cut-out. All it takes is _just_ above and as far as the switch is concerned it's as good as "stop".

And, yes, I'm sure there's an electromechanical assist in there so the contacts will "make" and "break" solidly, not drift in and out solely on the spring compression...

[dpb]

Wasn't garbled at all; says exactly what I wrote and meant -- the replacement pump doesn't have to be a jet pump, any of about same rating and similar pressure boost will serve the purpose. Whether any cheaper or not I don't know, but pumps are dime a dozen kinds of articles...

All that matters is that it has the same form factor; whether there's a single or a couple pretty-much universal for jet pumps I don't know but I'd guess there are a fairly limited number of designs for any given pump size class so it's probably not too hard to find one that will work.

As for the frames, those are standardized _excepting_ if a vendor did build a custom item for a given distributor like you say Marathon may have done for GE...in that case the standard may be close but they may have modified something just enough that you had to stay with them for parts...

[trader_4]

, that's supposed to be verboten. Saying two phases is pure heresy. Where w ere you when we were having that long electrical engineering discussion abo ut what 240/120 service really is in the other thread?

Forgot to add, you should find out why it's not grounded. For starters, the green supply ground wire should ground the motor and since the pipe is ste el, it should be grounded too. Probably it is, maybe you just didn't have a good connection to it with the test probe.

[dpb]

Since they're paired and not stacked, the second adds volume but not pressure, so it's only more like 2.3 psia.

On the latter, he's got a pressurized pressure tank just upstream a couple feet that's producing the static pressure reading since the system is still full...

[Dean Hoffman]

Answered in another place. A farmer solution would be to replace the pressure switch since it's the easiest and cheapest to try. There's no way to know if your pump motor's inherent protection is kicking out and resetting unless you happen to be there and can feel if the motor is getting hot. You might want to think about using a hose on the intake of the pump if you decide to replace it. It would ease replacement if you can't find a duplicate pump. Maybe Sharkbite or similar fittings on the output side also. I think there are cell phone apps available that would call you if the water level in your storage tanks drops too much.

[dpb]

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Well, there was one short chunk of PVC at the pressure tank, who knows what's been done elsewhere... :)

[dpb]

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Ignore that, you're right, I was again thinking of the 2.3 ft/psi instead of 0.43 psi/ft...

[dpb]

On 8/14/2018 9:12 PM, dpb wrote: ...

That of course is only if you're trying to replace the motor and keep the pump.

Like T4, I think the better course given their age is just replace both and be done with it and get another 30 years.

[Dean Hoffman]

I'd never heard of the two pipe system until you mentioned it. So I had to look it up. Popular Mechanics has a short article. I'm in an area where a single pipe system is good enough. We used to have artisan wells here. I don't know if any of those are still working.

[dpb]

On 8/15/2018 5:35 AM, Dean Hoffman wrote: ...

I think they graduated to sculpture... :)

"artesian"

There were a number in low-lying areas around here, too, but the water table has now dropped sufficiently owing to widespread irrigation that I'm unaware of any still running.

[Arlen Holder]

Thanks for confirming how the pressure switch works.

I ran some more tests today, where what appears to have happened is that there may be an electromagnet of some sort because something snaps those contact closed with a bit of force that I had to overcome with the wooden stick and then it wouldn't re-engage (so it's not just a mechanical spring).

I agree with your assessment.

Hopefully I'll test more for sure today as I left the booster pump ganged circuit breaker off all night so there is no water pressure in the house at this moment.

[Arlen Holder]

Oh? Yikes. I didn't know about Fretwell. I didn't even think that there's anything wrong with using the word phases but I agree that there are two different concepts going on, where the three lines emanating from a power plant are definitely three phases at 120 degrees apart, but by the time two of those multiply-stepped-down lines hit my transformer, they're in a center-tap transformer configuration, which isn't the same thing.

But I think I'll try to stay out of phase discussions as this is about booster pump motors.

It is?

I only come here when I have a problem to solve. :)

I'm not really all that concerned about "phase" terminology though, but I can imagine that others are - so I appreciate the warning to use my terms more delicately.