Author Topic: Another Grundfos SQE with CU301 control replaced with CSV  (Read 3415 times)

Cary Austin

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Another Grundfos SQE with CU301 control replaced with CSV
« on: September 20, 2014, 11:29:50 AM »
Well, it’s done. I finally swapped out my Grundfos CU301 well controller for a CSV1Z Cycle Stop Valve. This was the fourth CU301 that failed in my home in a little over 3 and a half years of home ownership (new construction). The original CU301 didn’t last through construction and was replaced prior to our moving in. It failed about 4 months after we moved in prompting another replacement, all under warranty. Eighteen months ago it died again which cost me $750 to be replaced, $500 of which was refunded to me by the well guy after I pointed out that it should still be under warranty (he subsequently told me that he ended up eating that cost). The latest CU301 passed in the night in early June prompting me to swear that Grundfos would never see another nickel of my money.

 The flat out failures were a pain, but so too were the intermittent failures, the low pressure incidents that caused a chain reaction and dumped all the water in the house onto my basement floor, the air in the lines a number of times, and the curious behavior during low-demand times (like when the water softener recharged). All of those things added up and totally turned me off to this system.

 The plumber couldn’t make it out the day it died so I took matters into my own hands. Now, I’m not a plumber and I don’t play one on the internet, but I’m an analyst and problem solver and I figured that I could solve this problem – by myself – and have it exactly how I wanted it…..and of course have no one else to blame by myself.

 If you look at the CU301 Installed picture, you can see a few things that at first don’t make a ton of sense but once you’ve been to 35 home improvement stores, things begin to click. The water main comes in through the wall on the lower right side of the picture, travels to the left and terminates into a manifold. These things are stock pieces that every plumber uses when they install a well pump and they have standard fittings and the same number of holes and such. From what I can tell, virtually every plumber builds these things the same way, all using a manifold such as you see here. The pressure sensor for the CU301 is right above a pressure bleeder that will fill your basement with water if something goes horribly wrong. To the left of that is the pressure gauge, then the pressure tank and below that the draining spigot. The manifold ends and in my case, the pipe travels up and has the main valve, then back to the right a bit, and then up once more into the domestic water supply.

 To get myself back in business when the CU301 died, I needed a pressure switch, a 3” piece of brass pipe to thread into the switch, and a connector to convert the ½” extension pipe to the ¾” hole left when I removed the CU301’s pressure sensor. Next, the pressure sensor is wired to the electrical box. I opted to use flexible conduit and ran my wires through there. The pressure switch has spots for 4 wires, two FROM the electrical box, and two more back TO the electrical box. The Grundfos setup only uses two wires so you don’t need one of those goofy pump controller boxes they sell, I just took the wires from the panel that were in the box, hooked them up to two wires going to the pressure switch, then wired the two wires coming back from the pressure switch to the well pump wires. Once I got my arms around what needed to happen, it only took a few minutes. The power was switched OFF for this. Then all I needed to do was shut off the water supply to the house, remove the CU301’s pressure sensor and screw in my pressure switch assembly.

 So now I was back in business. My CSV1Z arrived in a few days and I took it to my favorite local hardware store and started looking at parts to connect everything up. The idea here is that you have to remove a section of pipe from between the inlet into the house and the manifold and install the CSV there. This can be tricky. I’m not a pipe-sweater guy and this could be tricky, especially with the lack of real space, lack of experience and lack of stuff do it with. I ended up with a pile of connectors, fittings, flux, soldier, cleaning cloths, etc to the tune of about $40 bucks. Then it occurred to me that maybe there was a better way. So I dug around a little more and sure enough, I found appropriately sized SharkBite connectors. All I needed was two. The thread onto the CSV with some Teflon tape and clean pipes. I cut the pipes down as needed, cleaned them up good with the reamer and 3M Scotchbrite pads and reassembled the whole thing. The more savy people will notice that there is a 2nd Sharkbite connector on the upper horizontal piece of the completed assembly. That’s not a mistake. The original setup intruded slightly into the adjacent room so there was no room to open or close that valve once a wall was put up. I elected to shorten the whole assembly and add two supporting brackets under the lower part of the assembly, one on either side of the manifold. This also gives options down the road – if I need to change anything or swap out the Sharkbite connectors, I can do it without having to do any cutting or soldering.

 Anyway, that’s the assembly. Lot’s easier and less intimidating than you’d think. Adjust the pressure switch and CSV per the instructions and go back to enjoying your life!

 But, how’s it work!! Well, with the pressure switch alone, a shower with a single shower head going was clearly cycling. The flow would slow down very gradually and eventually jump up dramatically as the pump kicked in and the pressure rose quickly. This cycle continued for the duration of the shower or whatever you were using water for. Once the CSV was installed and set up, the pump kicks in shortly after there is demand for water and then stays on for the duration at the pressure you’ve set the CSV for. That assumes you set up the valve correctly. I had originally had the pressure switch too low so the pump was still cycling. Adjusting it so the pressure switch cut-in was just slightly below the pressure of the CSV did the trick. It works great now.

 All in all I’m very pleased with how it works. I’ve been living with it now for about 5 weeks and there hasn’t been any issues with the valve. It’s working exactly as advertised. I’m looking forward to many carefree years of service from this setup.

 Thanks for all your help, Cary.

 Richfield WI