Grundfos VFD and CSV

[laynes69]

I'm sick and tired of messing with our deep well jet pump. The system keeps losing prime, the pressure sucks and the setup is over 20 years old. We decided to remove the jet pump for a submersible pump and to get rid of the well pit. Upon speaking to the well company, they don't install many cycle stop valves or constant pressure systems. I like the sounds of a CSV, but will the system be compatible with a 3" grundfos pump? If the cost of a CSV is comparable with a standard setup, I'm leaning in that direction.

 

[Valveman]

The CSV works fine with the 10,700 RPM, 3", SQ Grundfos pump. But unless the casing is small I prefer their standard 4", 3450 RPM pumps. Depending on which SQ pump you have and the quality and depth to water in the well, the CSV will cost anywhere from $63 to $200. That should be several hundred less than using a CU301 box that cost 800-1000 bucks. Not to mention the CSV has no electronics, last longer, and makes the pump last longer than a VFD, which is what the CU301 box is.

 

[Sponsor]

 

[laynes69]

I was under the impression all of the 3" pumps were VFD, but I guess not. The driller said it's about an 800 dollar pump. I believe the casing is a 4" cast, and the well is from the 50's (guessing...no drill record). He quoted over the phone in the $2000 dollar range, so I guess it wouldn't be the VFD. I take it the softstart is not part of the variable drive then? The well is around 65' deep, and they will bail the well and clean things up before installing. If I can eliminate a large holding tank and prolong the life of the pump as well as constant pressure, that's what I'm looking for.

 

[Valveman]

The SQ has some electronics including the soft start thing in the motor. You have to add the CU301 controller and a pressure transducer to make it variable speed. But without the CU301 controller you can just hook it up to a regular pressure switch and use a CSV to get the constant pressure. I help people replace those CU301 controllers everyday and switch control of the SQ pump to a CSV and pressure switch.

 

[laynes69]

So the installer could just use a smallet pressure tank, the normal pressure switch, and all I would need is the cycle stop valve? Like I say, he's not too familiar with them, and around here nobody I know has them, but it shouldn't be an issue.

 

[Valveman]

So the installer could just use a smallet pressure tank, the normal pressure switch, and all I would need is the cycle stop valve? Like I say, he's not too familiar with them, and around here nobody I know has them, but it shouldn't be an issue.

Yep. All you need is the CSV.

 

[laynes69]

The water has iron, but even without a softener it's not terrible. Which valve would be needed? Also is there a simple diagram for installation?

 

[Valveman]

The CSV1A would be best. See instructions and applications for the CSV1A.

 

[laynes69]

Okay. Thank you, I'll keep this in mind.