Grundfos Variable Speed Well Pump Failure

[Chuck B]

I had a new water well drilled for a northern Michigan cottage and used the Grundfos variable speed controller and well pump. The warranty was for two years. Now after four years it failed and I'm facing a $2000 pump replacement. There is 240 V reading at the well head so the pump is getting a call to operate from the controller and current is good. The variable speed controller called out a "no contact with pump" trouble code. We also circumvented the controller and directly connected the powerline from the shut off box to the Well lead and got 240 V but no pump operation. The installer said the copper wires that connect at the wellhead were a little blackened and thought it may have been a lightning strike but I think he's just dodging the problem. My immediate neighbors on the lake had reported no lightning strikes or problems. I would think if it was lightning which I doubt the Romex would be melted and the well cover might also be damaged. The pump operated fine the other morning on a sunny day before it failed. Seems very premature for a $2000 pump and or a $1500 controller to fail in just four years. Any experience with these items? Wondering if there might be some benefit to contacting the manufacturer but it's two years out of warranty. I'm wondering what really caused the problem. Thank you guys

 

[MI Well Drilling]

It sounds like a possible wire problem down the well. A ohm meter would help if you have one? I sell grunfos and they do have a 5 year warranty. You are on the right track hooking the lead and load wires together because the grunfos SQE will work as a standard pump would. Borrow a ohm meter from someone and check the wire resistance down the well. The original installer may have rubbed the wire putting the pump in and it's taken this long to melt through.

 

[Sponsor]

 

[Craigpump]

Yeah 2 years, BUT if he is a Grundfos Water Pro dealer it's an additional 3 yrs for a total of 5. That won't cover the labor, wire or accessories, but it will cover the pump and controller.

I'd ask face to face if he's a Water Pro Dealer and ask about what it entails, discounts, extended warranties etc... see what his reaction is. Check with Grundfos to see if he is a Water Pro Dealer, if he is and won't cover it.....

Google Grundfos Water Pro warranties....

 

[MI Well Drilling]

Most drillers that push that grunfos line vary well should be a key dealer. Hopefully he will cover his workmanship as well. Manufacturers warranty is definitely 24 months. But key dealers get 5 years. 99% of the time the grunfos box is correct and in this case "no connection". Cross your fingers it's just a skinned wire.

On another note with your system. A big mistake installers often make is mounting the little tank upside down. Just something to check for

 

[Valveman]

We have been replacing those for so long and so often that we even have a little diagram. We normally just have to replace the VFD controller (CU301), as the pump was fairly dependable by itself. But we are seeing more and more pump problems as well. The controller sends a radio signal down the same wires as the power to the motor. So when the controller looses connection with the electronics in the motor, the system reverts back to working like it has a regular pressure switch with a 15 PSI bandwidth, like 45/60. When that system first came out you would get a “loss of signal” alarm after the pump had cycled 250 times without making connection to the electronics. Later versions changed it to cycle 500 times before showing a fault. I think the most recent change was to make it cycle 1000 times before showing a fault.


This probably leads to fewer controller warranties, but I am afraid it is increasing the number of pump/motor failures. I wonder how many times those pumps cycle 800-900 times, finally get a connection that only last a while, then cycle another 500-600 times, and so on. There could be tens of thousands of cycles on those pumps before anyone knows there is a problem. I would expect most still make it at least past the warranty period.


See the following link for the diagram to the VFD repair kit. This will replace the controller, but there is nothing I can do to put the smoke back in the pump. Maybe it is just a wire going down the well, as all that cycling torques the well each time and could have chaffed the wire. But if it is the pump and you have 4” or larger casing, you might want to consider a regular 4” submersible pump.

http://cyclestopvalves.com/csv-vs-vfd_1.html

 

[MI Well Drilling]

Grunfos pumps are pretty durable soft starting pumps. If it's a 4" steel well you may consider keeping the slim grunfos mini sub knowing how Michigan water is. But with a cycle stop valve instead of the expensive control. Still need the little tank.

A OHM reading on each leg would be helpful right about now.