Gen-X Mak4 pumps

[Hooked]

So Cos how do you like the new pump? The little one I have on my chiller CL is virtually silent. I'm hoping the larger ones will also have that quality.

I haven't gotten my probelm fixed yet. There is a 90 degree bend in the intake line within six inches of the pump. I plan on working on that the weekend after Easter. Do you agree that is a likely cause? I'm asking because it is going to be difficult to find a place to put the pump without that 90 in there and I hate to go to all the trouble only to find I still have the problem. Also is it likely my pump impeller is damaged and the pump will need to be replaced?

Thanks

[Cosmic]

I haven't gotten the new pump yet. It should be here by middle of next week I'm hoping. I'll be sure to post back on my opinion of it when I DO get it running though

If it's just a loud hum you hear, I doubt you will need to replace the impellar. Most likely scenario is the elbow is just restricting the intake of the pump, sort of like cutting it back by using a ball valve. Once open, the pump won't be restricted and should run normally for you. If the impellar IS bad, you would most likely be hearing "crunching" noises coming from the pump.

Is there a reason you need the elbow on the pump intake? What about moving the pump further from the source, so that a longer (read over 6") extension is needed before the elbow? This may be a bit easier, but I can't say without knowing more about how everything is set up.

Just a thought,
Cos

[Caterham]

Katrina,

I always like to start this explanation by relating it to the rear end in a car. In a car, the rear end (or drive end in case of front wheel drive) has what is called a differential. The purpose of the differential is quite simple, and can be applied in any pump application.

When we take a corner in a car, the wheels are required to spin at different speeds. If you take a 90 degree right turn into your driveway, the right side wheels have far less distance to travel than the left hand side. In this situation the left hand, or the "outside" wheel is turning several more revolutions than the inside wheel to make the same turn. Both sides of the car end up pointing the same direction when the turn is over but the outside wheels travelled further. Pretty simple concept. Lets proceed

On the suction side of any centrifugal process pump, the same rules apply as far as making the turn. In your case, the saltwater on the outside must travel further than the saltwater on the inside of the 90 degree turn. Also, just as the outside wheel on the car starts to go faster (more revolutions), the saltwater on the outside of the 90 degree fitting is travelling farther to reach the same destination. The problem now is that the velocity of the saltwater on the outside of the fitting has increased as it is trying to catch up. As the velocity of any fluid under pressure increases, the pressure drops. Now there is a velocity differential, thus a pressure differential right in front of the impeller. Not good.

Books with over 500 pages have been written on this topic and I am not going to bore you with a bunch of scientific crap. Get rid of the 90 degree fitting. If you must use it to make your set up work, then allow 10X the diameter of the pipe BEFORE the fluid hits the impeller. There must be a straight shot of pipe going into the pump. This will give the fluid a chance to equalize pressure and the impeller will treat it all the same. If you have 1" pipe, allow 10 inches of straight PVC before the pump and so on.

Also, never throttle back the discharge of a pump. NEVER. This creates a hydraulic force within the pump that tries to bend the shaft. Its not my opinion, its just the laws of physics. If the pump is oversized and creates too much flow, just install a discharge bypass. This can be done with a simple T fitting and a ball valve. Install the T fitting on the discharge of the return pump just at the top of the sump, immediately followed by the ball valve. Run a line off the T fitting back to the sump. If your pump is oversized and creates too much flow, throttle back your bypass valve and divert the water back to the sump. This will give you the perfect amount of flow to your display and let your pump operate close to its best efficiency point (BEP). When a pump is running off of its BEP it runs hot, wastes energy and always ends in premature failure.

Get your plumbing straightened out first, then determine if the pump has been damaged. You might find that the pump operates to your liking when properly piped. It could have sustained some damage depending on how long it has been running in its current environment. The GEN-X is a good pump.

If you have any questions about setting up your pump, please do not hesitate to ask. I want to help!

[Hooked]

That is a great explanation, thanks.

My pump is not oversized, I want to run it wide open, but the bubbles were driving me nuts. I'll reconfigure the plumbing based on the guidelines you provided and report back!

Thanks for helping

[UnderWaterParadise]

Any updates on this? I am trying to read as many plumbing and pump threads as possible

[BoomerD]

The one I bought before I had my knee surgery ended up being NOISY as H3LL!! I got p.o.'d and tossed it in a box and there is sat for a couple of months... Finally got it out and fiddled with it...turns out the noise came from a bent fan fin. Straightened it out, and it's fairly quiet. Sure moves some water! Even though a Mag 12 is rated at the same GPH, there's NO comparison. The Mak4 kicks butt, but is considerably more noisy than the Mag 12. It's probably going to be a closed loop pump for my 180.

[tommyp]

Mine is still loud but pumping strong as well

[Hooked]

I finally got rid of mine. I re-configured the plumbing based on Cateham's explanation and it did quiet down a little; however, the microbubbles did not go away.

This is the pump I'm using and I highly recommend it

http://www.premiumaquatics.com/Merch..._Code=Panworld

HTH

[BoomerD]

Heard good things about those, PanWorld AKA Blueline pumps have apparently improved inthe past couple of years, either that, or the earlier reviews were written by hacks...never can be too sure about that! Glad you solved the microbubbble issue...

[UnderWaterParadise]

Those Gen X pumps are dirt cheap compared to others

[Dennis7]

I have 2 Gen X Mak4 pumps, both bought at the same time. One is quiet and the other is louder like it might not be balanced. Both have been running for a year and a half. No problems with them except the one is little louder. I also have a Mak 5 pump of theirs which has been running for 9 months no problem.

[Dennis7]

I also have a Bluline pump which has been running for 9 months.
It's their smallest model, 480gph. Extremely quiet and smooth running, but it also runs hotter thsn the Gen X pumps. The casing is hotter to the touch.

[Hooked]

Dennis I have that same pump running the closed loop on my chiller and it is hot because it's not vented. The larger one I have is vented and doesn't run so hot.