Author Topic: Grondfosn 11SQF Well Pump (Read 1799 times)

JRHill · « **on:** August 11, 2020, 07:46:14 PM »

We have had this pump for ten years. It's been great.

Recently the stream goes down to nothing. Then it comes back up shortly afterward. I thought the pressure tanks might be low (we have 2 80g WellMates in series) and sure enough, they were a little low for the line pressure. So I aired them back up to spec. Afterward the stream is still going down to zero then it comes back up and works great until the next cycle. Otherwise all works wonderful. Our well guy is a good 'ol boy. He is about worthless unless you have a standard AC submersible. For this new fangled stuff he just wants to change everything out. NOT.

So my question: does anyone know if the 11 SQF pump has the low water sensor built into it or is that an option? There are just too many places to be at the same time to troubleshoot this and I'm trying to gather information. I also have the CU100 controller but bypassed it years ago in favor of a plain 'ol DPDT pressure switch. But the CU100 can receive codes from the pump through the power line. I was thinking of hooking it back up but I don't want it to control the pump based upon line pressures. With the CU100 the pump always has power so it can communicate and turn the pump on and off via the signals through the power line. With a standard well pump pressure switch it opens the line so the data signals don't to the pump from the CU100 controller unless the switch is closed.

Any one have experience with these wonderful pumps?

Best,
JRH

hedgerow · « **Reply #1 on:** August 12, 2020, 09:48:48 AM »

I have some experience with one years ago. BIL had a remote cabin. Well driller drilled a new well and installed one. I installed pipe and wire to the house and set the tank and controller up. This one was set up a little different than yours as it only had a three gallon tank so the controller would bring the pump on right away. This one didn't have a low water sensor that I ever saw. This area had a lot of what we call flour sand and that pump didn't like that at all. If the pump took a few extra amps to get started it would fault out the controller. A couple of the controllers went bad in a short period of time. Within five years the pump was pulled and replaced with a normal three wire pump with a regular pressure tank and a inverter to go from his battery power to 220 AC. Make sure your tanks are empty when you check you air pressure and it should be 2-4 PSI lower than your setting on your cut in pressure on your switch. You either have a tank, switch problem or the pump is going bad and not coming on right away when the tanks are going empty. I am guessing your have two tanks because the well is low producing?

JRHill · « **Reply #2 on:** August 12, 2020, 12:07:13 PM »

Yeh, I have a couple of priority to-dos today. I need to drop my 'lil weighted bobber down the column and check the head water level. I last checked it 7 years ago so its time. The column was drilled to 190 and the pump was sent at 170 with the head at 145 as I recall. Also need to swap the pressure gauge at the tanks as it is now accurate anymore.

We have some critters to water and garden and house use. The well is on its own solar with a 48v bank and 4 195 watt panels. It clouds up pretty heavily for many days in a row in the winter and there have been times when the batteries got pulled down too far so I added the 2nd tank for the extra capacity so I don't have to throw the transfer switch and run the generator as often. Actually, never since the 2nd tank was added. We will get some sunlight sooner or later and the extra time really helped.

If I free flow from a hydrant for much more than 20 minutes I 'may' pull the water level down enough to start sucking air and that's no fun. So I use the hose ball valve at the hydrant to keep a smidgen of back pressure on the system. Have never sucked any air since.

sharp edge · « **Reply #3 on:** August 12, 2020, 01:10:21 PM »

Sounds like to much air in the tank. Why did you put a pressure switch on it? Is that normal on a solar system. It probably has a built-in low water safety, otherwise it would be burnt up by now. my .02

SE

JRHill · « **Reply #4 on:** August 12, 2020, 05:33:35 PM »

Quote from: sharp edge on August 12, 2020, 01:10:21 PM

Sounds like to much air in the tank. Why did you put a pressure switch on it? Is that normal on a solar system. It probably has a built-in low water safety, otherwise it would be burnt up by now. my .02

SE

That was my original question: does the 11 sqf have a low water sensor built in on the pump? After 10 years if it was built in you'd think I'd know. But no, I can't reason through it. That's why I'm asking for someone who has one like mine. This pump is smart. It does a wild range of AC (60 to 260+) AC and DC (45+ to 280DC). It doesn't matter the connection - even reverse polarity. It just figures it out and runs. It's hard to make a mess of it.
But to answer your question:
I had to put a pressure switch on it. If not it could blow everything if it didn't shut down due to pressure.
I am draining everything down and starting from scratch.

JRHill · « **Reply #5 on:** August 12, 2020, 06:45:13 PM »

Quote from: hedgerow on August 12, 2020, 09:48:48 AM

I have some experience with one years ago. BIL had a remote cabin. Well driller drilled a new well and installed one. I installed pipe and wire to the house and set the tank and controller up. This one was set up a little different than yours as it only had a three gallon tank so the controller would bring the pump on right away. This one didn't have a low water sensor that I ever saw. This area had a lot of what we call flour sand and that pump didn't like that at all. If the pump took a few extra amps to get started it would fault out the controller. A couple of the controllers went bad in a short period of time. Within five years the pump was pulled and replaced with a normal three wire pump with a regular pressure tank and a inverter to go from his battery power to 220 AC. Make sure your tanks are empty when you check you air pressure and it should be 2-4 PSI lower than your setting on your cut in pressure on your switch. You either have a tank, switch problem or the pump is going bad and not coming on right away when the tanks are going empty. I am guessing your have two tanks because the well is low producing?

Hedgerow, You nailed it. I drained everything down to zero. The tanks were 2 psi lower than the settings on the pressure switch. The pressures had crept up and I was 4 psi too high. That was it. I'm still going to check the column anyway.
Thank you. Some times a guy needs a kick in the rear.

Forestry boogie? Gosh, that could be dangerous.

tmarch · « **Reply #6 on:** April 19, 2021, 04:22:29 PM »

As to the question, the answer is yes, Grundfos pumps do have a low water probe, it is on the pump wire.

JRHill · « **Reply #7 on:** April 19, 2021, 04:29:27 PM »

If you want it. Above ground or pressure tanks, it makes no difference to the switch gear.

As for the pump in the well casing, yes, there is a low water sensor. It's only triggered once in 14 years. That was when a line broke above ground. As I recall, it didn't stop the pump. It just slowed down until I shut the system down and fixed the break. Lots of bubbles and burps but that was about the extent. Love that pump.

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