Need to change a defective run capacitor in my Harbor Freight pump. The original is 16 uF 240V. Replacements I have seen are either 15 uF or 20 uF. Don't know which way to go, a bit under or over.

Any help? Thanks

Either one will likely be fine for that little POS, I would go for the 15 if it were me, don't sweat it if the voltage is higher either just don't go lower.
Good luck,
Jon

quote:

that little POS

That's unrealistic criticism. It's a good pump for moving cold water, that's what it's designed for and sold for. People who push it beyond it's limits with hot or viscous fluids should be intelligent enough to realize that some components like the cheap capacitors should be replaced. Nearly all documented cases of this pump failing in BD use can be traced to capacitor failure and lack of overload protection. Both can be added for less than the cost of the next best pump in terms of cost and reliability. The simple solution is to run two HF-CW pumps in parallel with check valves. Then both or either pump can be run. Two pumps in parallel have about 130% of a single pump in terms of head or flow and usually adequate when pumping cool VO.

Some people consider the VW P-up truck a POS because it can't haul a box full of gravel without straining. Use the right tool, know it's limitations.

Thanks, and actually I have been pretty happy with the little motor.

Anyway, what I have learned surfing around tonight is that Capacitors are rate with about a 10% range so a 15 would be fine in place of a 16 since the 16 might actually run a bit low. But, it is better to go up in size, say 17.5 mfd. Its always ok to go up on the voltage rating, never down.

I am going with this unless someone explains that this isn't right.

John Galt, fair enough, I was going by hearsay and pictures I have seen of it.
Foxden, I am an electrician. You can trust what I told ya, its also the same as what you just said you found surfing around...
Jon

Using the larger cap will add a bit of start up torque, not something needed for this pump but is done all the time on older air conditioners or refrigerator motors that will no longer start running under the load of the compressor, the repair man simply adds a second cap in parallel with the original one, this added cap is referred to as a "Booster" cap. Standard large metal motor starter caps can be used as a replacement for the HF pump but you will have to mount the cap on the outside of the housing and run longer wires. Motor starter caps are cheap from surplus sources like surpluscenter.com

Well, it wasn't the capacitor after all. I replaced it and the pump doesn't run. No humming or any other sign of hidden life. Time for a new one unfortunately, but I have a spare capacitor for the future.

POS is not what I would call mine, it has processed over 8,000 gallons and out there working right now.

quote:

Well, it wasn't the capacitor after all. I replaced it and the pump doesn't run.

I have one I just did the same thing to with the same result; new capacitor with a slightly higher uF, and it does nothing. If I give the fan a nudge, it starts right up and flies, but a new cap. did nothing to help it start on its own.

Any insight on why?

quote:

If I give the fan a nudge, it starts right up and flies, but a new cap. did nothing to help it start on its own.

Any insight on why?

Could be the bushings or bearings are seizing up or possibly part of the winding is shorted out. If its possible to take the end caps off check where the motor leads connect into the windings and look for loose connections or damage. If its not buzzing or humming when power is applied then the problem is likely the later.
I understand that these pumps are under $40.00, thats called a disposable motor...
You guys can call it what you like but as someone who has extensive experience working with and on motors I will stand by my POS statement based on all I have heard about them on this very forum, the price of them and the look of them, until I have one in my hands to evaluate I cant see that opinion changing...
Jon

quote:

Originally posted by Jon Heron:
[QUOTE]If I give the fan a nudge, it starts right up and flies, but a new cap. did nothing to help it start on its own.

Any insight on why?

IF the thing runs fine when you start it and it ISN't the windings fried or bearings seizing, it means the cap is the wrong size. Personally, I would always go slightly larger but if this is what you did and it didn't work, then try the smaller one. The idea of the cap is to shift the frequency of the power in relation to the phase of the windings to make the motor start. If the cap dosen't shift the phase enough, the motor will run but not start as you have now.

quote:

I understand that these pumps are under $40.00, thats called a disposable motor...
You guys can call it what you like but as someone who has extensive experience working with and on motors I will stand by my POS statement based on all I have heard about them on this very forum, the price of them and the look of them, until I have one in my hands to evaluate I cant see that opinion changing...

I have pulled a couple of them apart. I think your opinion is currently well founded and accurate.
They are made as cheap as earthly possible and with the minimum in quality and safety. I also agree with the warnings that some people have tried to make others aware of and people don't want to listen to, that they are inherently dangerous.

For a group of people that so many have such pedantic over the top safety concerns over nearly everything, I can't see how anyone would use, let alone argue these pumps are OK.
Well I can see one way but I'm sure if I were to say that factor is likely ignorance, people would light up and flame me and to be honest, it's none of my look out what happens to other people who use these motors. There are none at my place and that's all I need to be thankful for and if others are happy with them, good luck to them.

What I don't understand though, is in the US particularly, there must be a whole bunch of well made ( in the USA even!) motors available still at a very affordable price's that would do a better and safer job than the Chinese crap. Veggers ( everywhere) seem so adamant about using these POS things though? For the cost of what you would save on a tank or 2 of fuel, you would have to be able to get a good, well made pump that would be safe and last a lifetime.

I like buying things that I know I'll still be using in 20 years time and can grow old with even if if does cost a bit more than cheap dangerous crap but maybe I'm just too old fashioned.

quote:

Originally posted by Ryan P.:
If I give the fan a nudge, it starts right up and flies, but a new cap. did nothing to help it start on its own.
Any insight on why?

Because it is a POS.

When someone complains that an item is a POS when it breaks down after using it for a purpose it wasn't intended, then then they get the Foolish Idiot of the Week award.

There are good N.American made pumps which will reliably work with BD and VO processing. Of course they cost 3x or more than the cheap HF pumps. N.Americans love to buy cheap import crap then complain about it.

I am compelled to agree with John on this one. It may be cheaply built to minimum standards but it is a cheap regenerative turbine pump that can do the job it was sold for well. It works well enough in the abusive conditions it is expected to endure during bio production and is a cheap outlay for people who can't or won't shell out for better quality. I prefer to buy high quality second hand pumps myself but a lot of bio get's successfully made with these cheap pumps and they have never killed anyone that I know about.

quote:

Originally posted by john galt:
When someone complains that an item is a POS when it breaks down after using it for a purpose it wasn't intended, then then they get the Foolish Idiot of the Week award.

What award should a person receive for continuing to support and recommending the use of this pump to unsuspecting new-commers for biodiesel production when they now know that it is totally inappropriate for this use?

quote:

Originally posted by Ant:
I am compelled to agree with John on this one. It may be cheaply built to minimum standards but it is a cheap regenerative turbine pump that can do the job it was sold for well.

Do you really have valid proof that it "can do the job it is sold for well?"
There is at least one report on this forum alone of this pump catching fire when it was only ever used to pump water.
What do you call a pump that has a history of catching fire no mater what it pumps due to an inadequate run capacitor and no thermal or over load protection?
POS?

quote:

Originally posted by Kevin Gray:
Do you really have valid proof that it "can do the job it is sold for well?"
There is at least one report on this forum alone of this pump catching fire when it was only ever used to pump water.
What do you call a pump that has a history of catching fire no mater what it pumps due to an inadequate run capacitor and no thermal or over load protection?
POS?

I'm not going to get into a long debate on this. I don't use them and don't care that much one way or the other.

One anecdotal report is not a history or valid proof of anything. Given the huge number of these in use it represents an insignificant blip, if anything at all.

I suggest you use your expertise to detail an upgrade procedure with parts list and sources that allows people to upgrade the run capacitor and add thermal protection. This should result in a cheap pump that better fits the standards you advise. Cheaper than buying a similar pump with these features already fitted.

That would be the positive approach to the situation.

quote:

Originally posted by Ant:
I'm not going to get into a long debate on this. I don't use them and don't care that much one way or the other.

Then why did you feel compelled to post supporting the pump?

quote:

I suggest you use your expertise to detail an upgrade procedure with parts list and sources that allows people to upgrade the run capacitor and add thermal protection. This should result in a cheap pump that better fits the standards you advise. Cheaper than buying a similar pump with these features already fitted.
That would be the positive approach to the situation.

Why would that be a positive approach to the situation? Why do you think it is necessary to do everything "on the Cheap" when it comes to making biodiesel?
The situation is that this recommended pump is a POS and should never be used to make biodiesel or for any other reason for that matter.
Why do you think I have the expertise to totally redesign a POS to make it safer??
The ability to spot a safety problem a mile away does not imply an ability to redesign it so it that it is less of a safety problem.
I can not understand why you still support using this pump for any reason, especially biodiesel production.
The solution is simple, this pump should never be used to make biodiesel.

quote:

Originally posted by Ant:

I suggest you use your expertise to detail an upgrade procedure with parts list and sources that allows people to upgrade the run capacitor and add thermal protection.

This would be my simple 4 step procedure for upgrading one of these pumps:

1. Take POS pump and remove Power lead from terminal box.
2. Fit removed power lead to quality US/European made pump.
3. Put POS pump in metal recycling Bin.
4. Use quality pump and enjoy years of reliable and worry free service.

In most instances, when you obtain a quality pump, steps 1 & 2 are unnecessary anyway!

It's a POS even on water. The quality of the pump casting is crap. Over half of them leak when installed using standard installation procedures. A full 1/3rd of them fail in the first month of use. Northern tool sells a good alternative for not much more.