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Grundfos Well Pump Failure - Problem and Solution

Grundfos Well Pump Failure - Problem and Solution

Update 7.7.16: Finally got back to the last troubleshooting step: connecting the pump directly to the battery bank. Yup, verified that the DC side of the pump has failed; AC still works reliably. The least expensive replacement pump found so far is $1850 Time to start building a 25' tripod....

Update 6.15.16; 3:11pm: The DC side of the pump has failed. It only works intermittently - almost by accident when it does work. So I'm on AC running off the house. This is also rather strange as in the past, when I tried to connect to the house (VFX3648 power) the pump would ALWAYS throw the GFI on the circuit. Works fine now. So I'm quite ill-at-ease at this point....

I sure wish there was a good source of info for Grundfos pumps/devices. Their dealer network is tied up so tight that you are really on your own for troubleshooting docs and info. And forget pump repair. Seems the only option is replacement and you are left with a really nice stainless steel boat anchor. Fortunately, their products are top notch. As long as you don't have a problem.

Update 6.14.16; 4:00pm; DC is working on the well dedicated components. Apparently the circuit was not open for long enough to clear the last cycle. All is "well." Now I can get to other chores - but water is kind'a important. I hope this thread can help someone avoid the dreaded service call from the local well company that has no clue about off grid stuff.

Update 6.14.16; 3:18pm: Reconfigured the pump wiring through the pressure switch and eliminated the CU 200 controller. Works like a charm on 120v AC but the DC circuit through the battery bank will not start the pump. I suspected a polarity problem but additional research on the topic says that DC polarity doesn't matter. I reversed the DC anyway - no change. I have no way of knowing how the well company configured the leads when connecting and setting the pump. Supposedly, it doesn't matter.

The well is on its own set of panels/controller/batteries from the house. Unfortunately, the pump doesn't like the dedicated DC anymore. TG the VFX3648 120vac is clean and compatible - works wonderfully. But I still wish to have the well independent of the house. Any input at this point is appreciated. In a conversation with the local dealer... they know no more about solar configurations that they did 5 years ago. Im about to make a big bet there is really something really simple awry here.

Hi Folks, just want to share this in case someone has a similar issue:

Yesterday AM I lost water pressure - the pump wasn't turning on or had failed. The well has functioned perfectly for 5 years. The pump is a Grundfos SQF 11-2 with a CU 200 Controller and a IO 101 AC/Generator module. I use a standard 80g pressure tank and switch. All voltages were present, DC or AC modes. The controller was indicating strange water level/pressure conditions but voltage to the pump was present. While troubleshooting and powering up and down several times, the pump just would not start.

Please note this: the Grundfos controller communicates with the pump via proprietary HF signals. While researching, I found that Power is "ON" to the pump continuously and the controller feeds it a signal to start or stop via the level or pressure switch.

I got suspicious of the controller and direct wired the pump to 120v, the CU 200 was removed from the circuit. (When disconnecting the pump and reapplying power, it "wakes up in "ON" mode.) The pump went through it's self check/delay, then fired right up and ran normally.

I also found out that many people have had malfunctions with the CU 200 in that the HF stop signal to the pump may be missed and the pump will continue to run until the tank over flows or the pressure relief "pops off" (hopefully you have one). I have never experienced this though, just beware.

So, the solution was to remove the CU 200 from the system and just run the power lines to the pump through the existing pressure switch. There is a little more delay in the start up/soft start sequence before the pumps turns on though. I also realized that I added an unneeded (expensive) and potentially unreliable component to the system with the CU 200.

Best,

Jim

Re: Grundfos Well Pump Failure - Problem and Solution

I currently do not own your pump but have been studying them tremendously. The only think I can think of that it seems you haven't tried is to eliminate the io 101 interface box and hook the pump directly to the solar panels...perhaps the switching mechanism in the box is bad? You obviously know the wires are intact all the way to the pump if it runs on a/c.

Other then that its pulling the pump out. I've seen kit to rebuild all the pump mechanisms for these, surely the company sells replacement circuit boards? If not I would be tempted to peel it open for inspection. Sometimes you can find a bad solderjoint or capacitor or something small wrong.

Do you still feel like the sqflex is a good purchase or would you steer me away from them?

Re: Grundfos Well Pump Failure - Problem and Solution

Rustyknife wrote:The only think I can think of that it seems you haven't tried is to eliminate the io 101 interface box and hook the pump directly to the solar panels... Do you still feel like the sqflex is a good purchase or would you steer me away from them?

Yeah, bypassing the IO 101 and connecting to the batteries is the next step when I get back to troubleshooting the failure on DC power. TG the well pump works fine on AC power. Also for the IO 101, the internal wiring is 16ga stranded... it's a little small for my liking.

As for Grundfos, yeah the stuff is priced like gold bars but I still believe it is very good equipment and I will stay with the brand unless I experience any more problems. My biggest dislike is the lack of documentation and the restrictive dealer network. But there are ways around the problem.

Best,

Jim

Re: Grundfos Well Pump Failure - Problem and Solution

Just saw your update and wanted to comment. You do not need to build a 25 foot tower. I know the sections come in 20 foot sticks, but fret not, you don't have to pull the whole length at a time. I just finished installing a 6sqf-2 this last weekend at 300 feet with no prior experience and was done is a couple hours.. I copied a tool I saw on the internet and made it for 30 dollars. Basically I used a scrap piece of schedule 80 pvc to size it right, At lowes they sell these vise grip style locking pliers that have a switch on them you can flick so they can't be accidentally opened. I cut the end jaws off them and welded them to 2 pieces of angle iron. Then i cut a 1" coupler in half and heated the middle with a torch till it was bright orange and smacked it with a hammer to spread it apart just enough to grip a 1 inch schedule 80 pipe. then it was welded to the angle iron to make a super awesome pump holding tool 9,000,000.

And as long as you keep the couplers on the pipe in the well and a metal "tee" screwed into the coupler, it cannot fall into the well. The only danger is the time it takes you to unscrew the first joint and reattached the "tee" to pull the next pipe, but you could build two tees to minimize the amount of time the well pipe is exposed.

I think if you build a tool like I did, and then you build another tool, basically another 1 inch coupler with a ring welded on it and a way to clamp it to the pipe ( another small set of vise grips?) you could pull 6 feet, clamp the pipe at the well casing, reset your ring welded pulling tool, pull another 6 feet, clamp the pipe, and keep repeating until each section is off. The risk is super minimal because the "tee" will still be at the top. You could pull whatever distance you wanted and 25 feet would be unneeded. Just something to think about.

Re: Grundfos Well Pump Failure - Problem and Solution

Thanks Rustyknife, that's appreciated and a nice tip. I hadn't thought of pulling a little bit at a time. The pump is working fine on 120VAC at the time so I'm balking/stalling on buying a replacement. But from the end of Oct thru the end of January the sun drops below the treeline at the top of the canyon so I'm on gen power to supplement the lost charging cycle. Having the pump on AC is not a welcome addition to the load at that time of year. Not to mention swapping it out during freezing weather....

Looks like I'll be making yet another "special tool." :-)

Thanks again,

Jim

Re: Grundfos Well Pump Failure - Problem and Solution

I searched around for options to repair Grundfos pumps. I saw several YouTube videos for disassembly but options for R&R are not looking good. Seems they only want to sell new pumps. It irritates me to "shelve" a $2500 pump 'cause I lost the DC side of operation so I went looking for repair options. Doesn't look good.

I really hate disposable society stuff. But maybe their pumps work so good that there isn't a business reason for R&R options and I am the exception?

Grrr,

Jim

Re: Grundfos Well Pump Failure - Problem and Solution

It is amazing what we throw away. There used to be tv repair men but now tvs are more expensive then they ever have been there's no one out there to fix them. Just throw it away and buy new.

I'm not going to lie. I want your pump so bad just so I can take it apart and see what's wrong. I just like seeing how stuff works. I work on automatic transmissions for a living.

I did have one last thought for you. You mention your system has batteries so I assume the pump can work at night. I also assume that means the voltage dc wise is 48 v dc. The pump can run on 30 to 300 volts dc. My one last thought is that there may be a high resistance somewhere in the wiring to the pump or the pump itself. The higher voltage of 110 ac was able to over come this resistance but the lower 48v dc is unable to overcome it and it causes the voltage to drop below the 30 volt threshold to run the pump. My suggestion would be to series tie enough solar panels to achieve the same 110 v dc or higher and wire directly to the pump. This could diagnose a high resistance concern.

Re: Grundfos Well Pump Failure - Problem and Solution

For clarification by directly to the pump I mean not using the battery system. Not literally directly wiring it. You should still have a switch that's capable of disconnecting a high voltage dc array in the circuit

Re: Grundfos Well Pump Failure - Problem and Solution

Rustyknife wrote:I'm not going to lie. I want your pump so bad just so I can take it apart and see what's wrong. I just like seeing how stuff works. I work on automatic transmissions for a living.

I made my living for quite some time by working on things I'd never seen before. I hit my limits when I get to the board level and that's what I expect to see here.

Regarding a high resistance conductor external to the pump, I doubt it mainly because of the way it failed. It happened immediately and only once did I get DC operation after starting to troubleshoot. Weather was not an issue. There was no EMI burst that I know of (hah). No wiring was touched/moved and the only connections are at the well head and in the "pit" that contains the pressure tank, controllers, and batteries. The connections looked like they were just done when inspected. No measured voltage drop or variances, no increased amp draw.

But here is one thing that baffles me: After the new installation, if I connected the IO101 pigtail to a 120vac GFI circuit, the GFI would immediately open whether the pump was running or not. It was noted that if I ever had to run the well on AC, then I needed to use a non GFI circuit. Now, the system runs on a GFI just fine and has not opened once. (I have a ground leakage meter but it measures from the 120VAC plug and I never seemed to have enough time to wire in a plug through each of the control components to find the offending device... my guess it was the pump and/or the wire length. Regardless, something changed and I think it is the pump logic. My gosh, think about it, the Grundfos pump runs on about anything you throw at it, Hz, AC/DC, reverse polarity... it just doesn't matter. There's a lot of magic happening in that small space, way down a hole and under water. Why didn't they take another step and add a bunch of caps to store and bleed out lightning hits? :-0

Anyway, I did file a note on the US.Grundfos site a few days ago. No response, go figure.

Best,

Jim

Re: Grundfos Well Pump Failure - Problem and Solution Pendin

After the summer of running off the AC, I got around to removing all the cables and cleaning everything up. There were a few questionable connections. The batteries (8ea 6v golf cart) have been disconnected during this time. I took a voltage reading from all of them, all read in the area of 6.3v except for one which was 4.2v, damn. Anyway, I moved the 4.2 to the end of the string were I could get to it easily. I reconnected everything.

I switched on the array and the Morningstar controller woke up, ran up to 60.5vdc and was delivering the normal bulk charge. I noticed a wisp of smoke around the 4.2v battery and grabbed my volt meter. The battery was reading over 16 vdc!! I checked the one next to it and it was around 7.5v. More vapor! Still over 16vdc. I killed/shut down everything real fast. I opened the quick release for the 3 caps on the 4.2v battery and vapor rolled out of the center cell, a little in the adjacent cell.

So I've got a bad battery (internal short?). Can anyone explain why it's voltage went so high? How could it be higher than any of the others in the string?

TIA,

Jim

Re: Grundfos Well Pump Failure - Problem and Solution

Bad battery is seen as a heavy load a to all the good batteries in series and those 7 are all wired into the shorted dead one and will ruin the 7 good.

For temporary fix remove/eliminate the shorted battery...that will give 42 volts [7 x 6] of happy batteries and that is better than what you have.

Adding a "new" replacement battery has issues as well due to not entirely matching the other 7 now "not so new batteries"

Checking specfic gravity of each cell regularly and logging the readings would have flagged this problem early on.

Re: Grundfos Well Pump Failure - Problem and Solution

I think to install Grundfos SP 3A Series pump, it's always better

Re: Grundfos Well Pump Failure - Problem and Solution

Hi folks,

Anyone out there with troubleshooting knowledge for the Grundfos 11SQF2 well pump? The pump only delivers 21psi (exactly 21 psi). On startup at zero pressure the pressure jumps/surges to 24psi then settles to 21psi very quickly. I have a hydrant in the line between the well pump and the pressure tanks/controls. There is no air coming out of the hydrant at startup and it throws a large volume of water but only to a max of 21psi. With the cap off of the well head and the pump running I can not hear any water escaping the pipe in the column. I believe I know the problem but was looking for expert input from someone else. Of course, in my area, I can't trust the well company to do anything other than to throw parts at it, starting with a $2000+ pump. I need help from an experienced, honest tech - not a parts swapper. Well depth 195', head at 165' and pump at 175'. There are no geysers between the 50' buried run from the well head to the well pit.

TIA,

Jim

Re: Grundfos Well Pump Failure - Problem and Solution

JRHill wrote:Anyone out there with troubleshooting knowledge for the Grundfos 11SQF2 well pump?

(embarrassed) I found it after a week of craziness: a trunk line to our cold frame blew a garden hose. We don't use the cold frame in the summer as its too hot and when it occurred to me to check it, and found the problem, I knew I was going to get thrashed. So there it is - confession is supposed to be good for the soul. Thrash away. It's so good to have enough pressure for a shower that I don't care (wink).