Sticking Pump Impellers

[howto]

I have 3 centrifugal pumps...

all draw water from the klong.

Two are cheap china 1hp...

and the third is good quality Italian 2hp.

Often they "freeze" and trip the breaker on startup.

As a last resort,

I "tap-n-bang" the intake metal with a small hammer.

Requires 2 people...

one at the breaker and other at the pump.

Anyone have suggestions of a "fix"?

Thanks for all suggestions.

[Wee Jimmy]

I have 3 centrifugal pumps...

all draw water from the klong.

Two are cheap china 1hp...

and the third is good quality Italian 2hp.

Often they "freeze" and trip the breaker on startup.

As a last resort,

I "tap-n-bang" the intake metal with a small hammer.

Requires 2 people...

one at the breaker and other at the pump.

Anyone have suggestions of a "fix"?

Thanks for all suggestions.

Maybe the inner shaft has a slight bend or the shaft has no centre bearing and you are getting a bit of a whip from the shaft as it starts. Could also be a bearing about to collapse?

[IsaanAussie]

I have 3 centrifugal pumps...

all draw water from the klong.

Two are cheap china 1hp...

and the third is good quality Italian 2hp.

Often they "freeze" and trip the breaker on startup.

As a last resort,

I "tap-n-bang" the intake metal with a small hammer.

Requires 2 people...

one at the breaker and other at the pump.

Anyone have suggestions of a "fix"?

Thanks for all suggestions.

Hi Howto,

Most well supplied water and groundwater in general here has high iron content. If could be that you have a build up of rust/mud in the pumps. Probably a good idea to pull one down and have a look.

Isaanaussie

[howto]

Perhaps, I thought about that.

But the 2 cheap units are 3 years old,

and the better unit is 2 years old.

However they all have cast iron impellers...

and I suspect the "mouth" of the impeller,

as it goes into the front impeller cover (also iron),

is rusting, therefore the impeller

may be seizing from rust.

Sorry I forgot to mention...

they are used 2x monthly and

I often titrate the klong water, it is a pH 8.

If the bearings in the pumps are going out,

only option is to replace the pump...

as they are not worth repairing.

Thanks.

[howto]

Thanks IsaanAussie,

(and thanks to Wee Jimmy)

Pardon me but I'm not a "forum expert".

I've the tools to pull the pumps down...

but it is the "fix" that concerns me.

I can't check for shaft runout, (my dial indicators are back home)

(which would/could indicate a bent shaft or worn bearings)

nor do I want to pull these pumps down every 2 years.

If I have to pull them down, then I need to fix them.

I would like to see 10 years from these pumps.

If the issue really is rust freezing

of the impeller mouth into the cover...

what is a better "fix"?

I thought about pulling the impeller...

and having a local shop "turn it down" ,

then banding it with non-ferrous stainless.

IMO, likely not worth the effort

Thanks.

After thinking about this for awhile...

a better solution may be...

"thump" the pump(s) to get it started then

just run the pumps for a minute daily.

Perhaps they just "sit" too long.

Cheers.

Edited September 7, 2009 by howto

[Gary A]

Look on the motor end of the pump. If you are lucky there will be either a place for a socket or a screw driver slot. If my pump is off for longer than a few days, I have to manually free it up before turning it on. Mine has a plastic cover that I must pop out before I can get to the screw driver slot.

[howto]

Look on the motor end of the pump. If you are lucky there will be either a place for a socket or a screw driver slot. If my pump is off for longer than a few days, I have to manually free it up before turning it on. Mine has a plastic cover that I must pop out before I can get to the screw driver slot.

Thanks Gary A...

Guess I'm not lucky, no slots.

Seems you have implied exactly what I was thinking...

let it sit too long and it may "freeze".

Guess I could take off the back cover (they are metal),

the fan shroud, and use a socket/ratchet.

All I need to do is just turn 2 cm in either direction.

Better than "thumping" the pump with a hammer.

Cheers and thanks again!

[Beardog]

Thanks IsaanAussie,

(and thanks to Wee Jimmy)

Pardon me but I'm not a "forum expert".

I've the tools to pull the pumps down...

but it is the "fix" that concerns me.

I can't check for shaft runout, (my dial indicators are back home)

(which would/could indicate a bent shaft or worn bearings)

nor do I want to pull these pumps down every 2 years.

If I have to pull them down, then I need to fix them.

I would like to see 10 years from these pumps.

If the issue really is rust freezing

of the impeller mouth into the cover...

what is a better "fix"?

I thought about pulling the impeller...

and having a local shop "turn it down" ,

then banding it with non-ferrous stainless.

IMO, likely not worth the effort

Thanks.

After thinking about this for awhile...

a better solution may be...

"thump" the pump(s) to get it started then

just run the pumps for a minute daily.

Perhaps they just "sit" too long.

Cheers.

Sounds like the older Chevrolet starters on cars & trucks . Rap with a hammer to break the rust free so the dam_n thing will turn over & start. It sounds like either rust or just the age of the pumps sucking up debri. I have used spray lubricant around the bearings in my pumps with limited success & you have to do it often. If you are only using your pumps intermittently I would try to spraying any amount of spray lubricant the bearing would accept. Most of the bearings used are not a sealed bearing pack as one would think. One of my impeller pump drives churned up enough mud & hard soil to compromise the part & is now in for servicing. Without tearing it down & having a look see it is tough to tell. With the Chinese units 2-3 years is a long time & maybe worth replacement. they are pretty inexpensive. If your good pump (The Italian one- I forget the name)might be worth repairing- but since the company has been repurchased it has been hard to get parts for. I did a bunch of research on this pump 2 & a half years ago. The part of most of the sites language is Italian kind had steered me away from purchacing the pump. That pump most likely is the bearings - The pump itself looks pretty industrial & would most likely grind up dirt 7 rock debris as it is made for industrial & irrigation( no house pumps). If you do have them repaired do it 1 or 2 at a time Thailand takes its sweet ass time to get parts & here cash is not king - Your just another number no matter how much you beg. Sad but true.

[c64]

I've been reading about the pump problems everybody have here with their pumps.

Have somebody tried to use a sandpiper pump to fullfill the pumping needs?

I know they're a little expensive but they'll chew rocks without a problem. They are air operated but with a little tech knowhow it might be doable to connect an electric motor with a gearbox to it. Best thing is that they are very efficient - up to 97 %

The pumps are bullet proof and the only thing that breaks down on the pump is sometimes the diaphagrams (wich is very easy to change). Grit, cheemicals, iron content is not a problem for the pump.A little search on Alibaba dot com revealed a couple of producers here in Thailand.

This is from wikipedia:

http://en.wikipedia.org/wiki/Diaphragm_pump

EDIT:

-------

There are also electrically driven diaphragm pumps on alibaba. Saw them for sale from 300 usd and up flow rate from 0,5 m3 - 20 m3 per hour.

Regards

Edited September 9, 2009 by c64

[Maizefarmer]

If this was a shaft or impeller issue of any sort it would be getting worse over time - which the OP has not mentioned - noise would be getting worse, or coil (pump motor would be getting hot and starting to smell) or there would be evidence of seals starting to leak .....

I dont think this is the pump at all ...... take the motor apart and check carbon/graphite brushes - this sounds like brush contact- bet you they'll be well worn, and chances are there'll be a load of dust inside as well. You're not getting good current flow to the commutator coil. Clean them out with a airhose, apply some WD40, put it all back together and all will be fine. Might as well clean the motor bearings as well while about it.

Does this pump have a starting capacitor wired into the switch - if its not the above, check the capacitor: it'll be breaking down. Theyre cheap as chips - it'll have 330 or 470uF or some similar figure on it @ 220 or 600v - take it off and go down to the hradware store - get new one, just make sure the voltage is figure is at least or more as the one taken off and the uF figure is within about 10% - 20% either way of the old figure - put it on (doesnt matter which way its connected - electrolytic caps are all bipolar on single phase ac motor) .

Do botht he above and your pump will start first time everytime

[howto]

If this was a shaft or impeller issue of any sort it would be getting worse over time - which the OP has not mentioned - noise would be getting worse, or coil (pump motor would be getting hot and starting to smell) or there would be evidence of seals starting to leak .....

I dont think this is the pump at all ...... take the motor apart and check carbon/graphite brushes - this sounds like brush contact- bet you they'll be well worn, and chances are there'll be a load of dust inside as well. You're not getting good current flow to the commutator coil. Clean them out with a airhose, apply some WD40, put it all back together and all will be fine. Might as well clean the motor bearings as well while about it.

Does this pump have a starting capacitor wired into the switch - if its not the above, check the capacitor: it'll be breaking down. Theyre cheap as chips - it'll have 330 or 470uF or some similar figure on it @ 220 or 600v - take it off and go down to the hradware store - get new one, just make sure the voltage is figure is at least or more as the one taken off and the uF figure is within about 10% - 20% either way of the old figure - put it on (doesnt matter which way its connected - electrolytic caps are all bipolar on single phase ac motor) .

Do botht he above and your pump will start first time everytime

Many thanks to Beardog and Maizefarmer...

Apolgize for the delay...

Yes Beardog, I do very well know 60's~80's starters.

And when I read your post it instantly kicked my brain.

Another symptom of starters are,

exactly as Maizefarmer described,

contact brushes to the armature.

That was/is a common problem of "hot" cars in that era.

I've had a few "hot rods"...

-- 1968 Chevy Chevelle SS 396, 400hp

-- 1969 Chevy Camaro SS 396, 400hp

-- 1970 Chevy Camero SS 350, 350hp

-- 1970 Chevy Nova SS 350, 350hp

-- 1970 Ford Mach I Fastback, Boss 429, 400 hp

-- 1970 MOPAR Dodge\Chrysler 1970 Hemicuda, 426 Hemi, 450hp

-- 1971 MOPAR Dodge\Plymouth 'Cuda 440 Six Pack, 400hp

-- 1971 MOPAR Dodge\Pontiac Trans Am 455 HO, >450hp.

Any of these takes a lot of juice to start in the wintertime.

Really hard on the starter.

Usually the solenoid, contact brushes, or bendix

As to pumps...

I likely have multiple issues.

Those being:

- sediment

- rusting

- poor electrical contacts

- perhaps a cap breaking down.

In every instance...

(excepting a cap breakdown, but all are external metal "run" caps)...

rotating the shaft 2~5 cm...

should/will allow the pump to start.

My best option...

pull the fan shroud from each pump...

drill a hole in it so a deep well socket

will fit through it,

and give the shaft a quarter turn.

That should work...

better than thumping the pump intake,

or rebuilding a old pump (for a while).

Yes, chinese pumps, they are not worth repairing.

Thanks for all of your input.

MaizeFarmer, excellent suggestions!

BTY Beardog,

I miss...

-- the firewall mounted starter solenoid,

-- and those small vent windows.

-- and my 1971 Pontiac Trans Am 455 HO, >450hp

Cheers to All.