Constant Pressure Pump

[Sparro]

Hello...
I've got a problem with my well pump. I had a Grundfos 3" SQE variable speed constant pressure pump with the CU 301 controller installed in my new home a little under three years ago.
I also have a Geothermal ground source heat pump running on an open loop system that uses my water well.
I have a strong well, 23 GPM flow. My heat pump requires 10-11 GPM to function correctly and i need about 3-4 GPM for my household water needs.
A few days ago my Grundfos well pump burnt out for whatever reason??? It does run alot because its used to heat and cool my home everytime the heat pump is running. I was told this should last at least 15 years, but it died.
Now I've been told not to go with Grundfos and the CU 301 because they die prematurely and they have had lots of problems with them.
I've been told to go with a standard 4" pump and get a Franklin Electric MonoDrive controller and use my existing 2 Gallon pressure tank.
I'm told Franklin Electric is a much better and reliable system.
Can anyone shed some light on this for me? I'm not sure what to do?
Do I replace the pump with another 3" Grundfos and run the risk of it burning out in another 2 1/2 years or do I get a 4" pump and a MonoDrive controller and hope for the best???
Any help would be greatly appreciated.

 

[Valveman]

You have already fallen for the variable speed pump hype once, don't fall for it again! The Monodrive or any of the other variable speed pump systems available are no better than the one you have. As a matter of fact, even though they have lots of problems and don't last very long, I have found that the Grundfos has been the best of all of them. When they say that variable speed pumps save energy, they are lying. When they say that variable speed pumps last longer, they are lying. When they tell you that a new style of variable speed pump will solve all the problems that were seen in the last model, they are lying. The pump guy probably actually believes this stuff himself, because he has been lied to by the manufacturers.

The VFD or variable speed pumps are what manufacturers call a "fluid product". A "fluid product" has nothing to do with water. A "fluid product" is one that cost a lot up front, doesn't last very long, is not repairable, and must be replaced with a new one. This keeps the cash flow "fluid" for the manufacturers. The fact that it is an important item that provides water, and in your case heat and cool for the family, means you can't be without it, and must replace it quickly. Hopefully you need a replacement so quickly that you don't have time to research alternatives.

The CSV or Cycle Stop Valve was designed to, and has been dependably replacing VFD pump systems for almost 16 years now. The CSV gives the same energy efficiency as VFD, and the CSV actually does make the pump system last longer while still able to use a much smaller tank. See the attached picture of one of the most recent Grundfos SQE systems that was changed out to a CSV system. If your pump would still run, we could have just replaced the CU301 controller and used a CSV. Since your pump is also fried, you should replace it with a more dependable, and less expensive, standard 4" or 3" pump. I prefer a tank that is a little larger than the 2 gallon tank you have, but if the bladder isn't already busted, it will still work fine. Install a CSV and a standard pressure switch, then you will have a dependable and long lasting system.

I have heard countless times that using a heat pump to save energy is a moot point if the pump system does not last. Replacing an expensive pump system every couple of years cost much more than a heat pump could ever save. The real savings comes when your pump system last 20 years, and that is what the CSV is designed to help happen.

Just do a search on this forum for "CU301" and you will see how several other people have solved this problem.

 

[Sponsor]

 

[Sparro]

Thanks for the reply Valveman.
I just picked up my Grundfos system from a local repair shop. He basically told me the pump motor went to ground for whatever reason. Could be a brownout, powerfailure... he's not sure.
He then told me that he's never worked on a 3" SQE pump and can't do much more for me.
I'm pretty sure the CU 301 is ok, I think it's the motor in the pump thats fried.
At this point my plumber has put in a temporary pump so I can get by.
Can you recommed the best set up for me?
I don't wanna make the same mistake twice.

 

[Valveman]

This is the way I would control it. Then I would use any of the properly sized brand name 4" pumps.

 

[Gary Slusser]

BTW, 3-4 gpm in the house.... a shower head uses 2.5 and a toilet flush at 1.4 gpm is 4 gpm. Filling a tub can be 8-9 gpm alone.

 

[Sparro]

My 3" Grundfos pump is stamped with 1.5 HP, 15 GPM. It's an SQE 290. I never felt a pressure change ever with it. My heat pump could be running, my wife could be doing laundry, the kids could be taking a shower and the water pressure was always great.
Today I was told by another pump guy that no standard 4" pump made by any manufacturer is designed to work 24/7.... he says my situation with the heat pump running all the time plus your household use its basically running all the time and a standard 4" pump would probably die before a 3" variable speed constant pressure one.

Now i'm really messed up... I just want someone who knows to tell me what the best thing is to do... I need to know what i should buy if i'm gonna replace my pump and controller.... whats the best out there that will last the longest????

 

[Valveman]

You need to find you a pump man that knows what he is talking about. All pumps, especially the 4" models, are made for CONTINUOUS DUTY. That means they are made to run 24/7. Cycling on and off or being abused by the voltage spikes, resonance frequency vibration, harmonics, and the many other problems caused by Variable Frequency Drives is what destroys pumps. I can tell you from my 40 years experience that a pump running 24/7 will last much longer than a pump that is cycling or controlled by a VFD. Sounds like this guy would really like to continue selling you a new pump system every couple of years.

You have already seen the average life of a VFD pump system. I don't think you have anything to loose, and you have everything to gain, trying a standard pump in the system. The CSV will hold the pressure steady the same way you are use to seeing with the VFD system. With the CSV, it will just be about 20 years before you have to think about this again.

Did you do a search for CU301, and see that there are many other people having the same problems with the VFD systems? Fool me once, shame on you. Fool me twice, shame on me. You will see lots of people on the Internet having problems with all kinds of VFD systems. You won't see very many people discussing CSV's, because they are not having problems and never even think about there water system. If you want more details, read a few articles at this link.

https://cyclestopvalves.com/pages/vfd-repair-kit

 

[nc73]

First of all, what size is your Heat Pump? Open loops only require 1.5gpm per ton, so that tells me you have a 7ton?

 

[Valveman]

First of all, what size is your Heat Pump? Open loops only require 1.5gpm per ton, so that tells me you have a 7ton?

This thread is 10 years old, but thanks for bringing it up. In 10 years, nothing has really changed. However, there are now dozens of new/different brands of VFD's to choose from. The SQE has been through several more modifications as well. All the new modifications to the old brands and all the new models available, still have not been able to change the laws of physics or mother nature to solve the problems with VFD control.

The Cycle Stop Valve has not changed, as it is hard to improve upon. In the 10 years since this thread was started, thousands of VFD's have been replaced with Cycle Stop Valves. In the last 10 years at least many VFD manufacturers have stopped claiming a VFD saves energy, as there have been lots of new information they cannot dispute.