Question about pressure switch

[liteguy1]

Hello All,

My first post. Just installed a Grundfos 6 SQF-2 pump sitting at 350' in well. Connected directly to 48 VDC batteries, I get 4GPM. In the process of hooking up the PV panels into the Grundfos CU200 smart box. The option for pressure switch is the same as the float switch according to Grundfos.

The pressure switch is a Square D type as described below. My question is, nowhere can I find a wiring diagram of how these two pieces connect. The CU200 smart box is two wire and the Square D pressure switch is 4 wire contacts. Any help would be greatly appreciated.






"The Square-D pressure switch is “reverse action” switch designed to be used with the Grundfos CU200 switch contacts. The pressure switch wiring is connected to the “float switch” control terminals in the CU200, just like a float switch would be. In that circuit it’s not carrying any of the PV power current. It’s just providing a contact closure to signal the CU200 to turn the pump off and on. It’s not meant to be installed in the PV power current path. The CU200 does that.

Grundfos does not make their own pressure switch for the SQFlex pumps. The Square-D switch is what they recommend.”

[Mike90250]

Did they not include instructions with the kit ? Try the dealer you got it from. If I saw it and had a meter, I could figure it out I think.

[inetdog]

The four wires in the SquareD switch could be two identical contact sets for separate circuits or could be one NO contact set and one NC contact set without a common wire between them.
As Mike said, a meter or the SquareD documentation (online once you have the part number) should tell you which two wires to use.

Note that when the Grundfos is powered by a DC circuit a standard float or pressure switch in the power path cannot be used because the pressure switch will generally not have a high enough DC rating.

[liteguy1]

Did they not include instructions with the kit ? Try the dealer you got it from. If I saw it and had a meter, I could figure it out I think.

Thats been my complaint, No instructions and the dealer I would never use again

[liteguy1]

The four wires in the SquareD switch could be two identical contact sets for separate circuits or could be one NO contact set and one NC contact set without a common wire between them.
As Mike said, a meter or the SquareD documentation (online once you have the part number) should tell you which two wires to use.

Note that when the Grundfos is powered by a DC circuit a standard float or pressure switch in the power path cannot be used because the pressure switch will generally not have a high enough DC rating.

The float switch or in my case the pressure switch is installed to the CU controller. Grundfos website shows both however I cannot find the schematic, guess I'll have to contact Grundfos to see how they are doing the wiring...The dealer said, "oh I've never seen this done before" Are you telling me that I'm the only guy on the planet who is the first to use a SQ D pressure switch with the CU200 controller.

Any body on this forum use a SQ D pressure switch and the CU 200 controller?

[inetdog]

The float switch or in my case the pressure switch is installed to the CU controller. Grundfos website shows both however I cannot find the schematic, guess I'll have to contact Grundfos to see how they are doing the wiring...The dealer said, "oh I've never seen this done before" Are you telling me that I'm the only guy on the planet who is the first to use a SQ D pressure switch with the CU200 controller.

Any body on this forum use a SQ D pressure switch and the CU 200 controller?

Can you give us the model information on the pressure switch?

[liteguy1]

Can you give us the model information on the pressure switch?

I have the SQ D pressure switch at work and will report back.

I have attached a couple of pictures including this link

http://www.sunshineworks.com/downloads/sqflex/Product-Guide-SQFlex-L-SP-TL-014.pdf

Page 17 shows the pressure switch, BUT, nowhere can I find an exact wiring schematic.

[liteguy1]

todays pictures

After a lengthy email conversation today with the Grundfos folks, I came up with this diagram from them. According to their engineer, The two wire coming out of the CU200 controller is non polarity and same with the SQ D switch relay. The two wires can go on either half of the SQ D being either lugs L1 and T1 or L2 and T2. Interesting that Grundfos wouldn't have this level of detail, but they do now. Hope it is useful for the next setup someone is doing like this. Thank you all.

[Texas Wellman]

I've never used a pressure switch with any solar pump but my understanding is that you just run a wire from the CU box to the pressure switch (only on one side) and then make the circuit back to the control box. When the switch closes it completes the circuit and the pump will come on.

I have wired in float switches and they work in the same manner.

After a lengthy email conversation today with the Grundfos folks, I came up with this diagram from them. According to their engineer, The two wire coming out of the CU200 controller is non polarity and same with the SQ D switch relay. The two wires can go on either half of the SQ D being either lugs L1 and T1 or L2 and T2. Interesting that Grundfos wouldn't have this level of detail, but they do now. Hope it is useful for the next setup someone is doing like this. Thank you all.

[inetdog]

After a lengthy email conversation today with the Grundfos folks, I came up with this diagram from them. According to their engineer, The two wire coming out of the CU200 controller is non polarity and same with the SQ D switch relay. The two wires can go on either half of the SQ D being either lugs L1 and T1 or L2 and T2. Interesting that Grundfos wouldn't have this level of detail, but they do now. Hope it is useful for the next setup someone is doing like this. Thank you all.

The key thing shown in the diagram is that the contact closure (whether float or pressure switch) will stop the pump. This is not the way that typical pressure switches are wired. (Hence the designation of "reverse action" for the pressure switch.)

[liteguy1]

Thanks All

[herbiehunter]

im looking for the same thing

have you found it yet

I have the SQ D pressure switch at work and will report back.

I have attached a couple of pictures including this link

http://www.sunshineworks.com/downloads/sqflex/Product-Guide-SQFlex-L-SP-TL-014.pdf

Page 17 shows the pressure switch, BUT, nowhere can I find an exact wiring schematic.

[liteguy1]

have you found it yet

Spoke with the Grundfos Engineer and he recommended a "reverse action" Square D pressure switch.

There are four terminals and starting from the left hand side I number them 1,2,3,4. From Grundfos:

1 & 2 is Normally Closed (NC) – Meaning the circuit is closed when the pump is running (opening the circuit will stop the pump and vice versa)
3 & 4 is Normally Open (NO) – Meaning the Circuit is open when the pump is running (Closing the circuit will stop the pump and vice versa.

Originally I had this wired with terminals 1&2 which intermittently when triggered off would not shut the pump off.
Grundfos had me change the wires to terminals 3&4 and since then I have had no issues with switching.

My well runs off of 48 volts presently but would like to run the system on 96 volts however I have been unable to find a 96volt charge controller.