Normally Open Pressure Switch

JR Hill · October 2010

Please help with a resource for this switch - all I can find is the std normally closed switches. From the Grunfos doc: "The CU200 pump control box should be selected, since it includes terminals for a pressure switch, which will control the pump’s on/off operation via the pressure in the storage tank. The pressure switch should be of a
normally-open configuration, where the contacts within the switch are in the open position when the pressure is below the maximum set-point. When the pressure in the system rises to the maximum desired pressure, the contacts will close, signaling the pump to shut off."

Looking for a 30-50# range or adjustable close to that range.

Thx folks,
JR

dwh · October 2010

Re: Normally Open Pressure Switch

http://www.google.com/search?q=pressure+switch+normally+open&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a#q=pressure+switch+normally+open&hl=en&safe=off&client=firefox-a&hs=gE3&rls=org.mozilla:en-US:official&prmd=ivs&source=univ&tbs=shop:1&tbo=u&ei=cZbLTPqtG9HhnQfzye3RDw&sa=X&oi=product_result_group&ct=title&resnum=3&ved=0CD4QrQQwAg&fp=2304850557947867

Can't Grundfos sell you the switch? Or at least tell you exactly which one you need?

PhilS · November 2010

Re: Normally Open Pressure Switch

I use the Grundfol CU200 to control my pump. I bought a relay from Radio Shack, used this great BZ controller box I had laying around, and now I can still use a normal well pressure switch with the Grundfos pump and controller.

Of course, there's a cover for the box that I've been able to use labling tape to hide the BZ info, now it just says "well pressure switch relay". Yeah, WAY too much box for the relay but it was something I had already that was doing me no good.

It was a pretty simple installation, lemme know if you want more detailed instructions should you decide to use a "normal" well pressure switch with the Grundfos system that is wired to accept a "float" switch hanging in a stock tank.

Attachment not found.

Phil

JR Hill · November 2010

Re: Normally Open Pressure Switch

Thx Phil, that's what I will do then. And thanks for taking time to snap the pix. So you just installed a COTS pressure switch and use it to toggle the RS relay? What'd you use for the relay power supply? Tap off one of the 12v batteries?

DWH, the Grundfos dealer is full service only. So after setting the pump, I took over. Besides, he obviously hasn't done much with hybrid systems and was misquoting (missing) the control/charging of the batteries... said that was built into the CU200 and he verified it with the Grundfos rep. The upside is there is obviously a business opportunity around here ;-).

Best,
JRHill

icarus · November 2010

Re: Normally Open Pressure Switch

http://www.coleparmer.com/catalog/product_view.asp?sku=6897352&pfx=

http://www.grainger.com/Grainger/wwg/search.shtml?searchQuery=normally+open+pressure+switch&op=search&Ntt=normally+open+pressure+switch&N=0&sst=subset&typeaheadSearch.x=35&typeaheadSearch.y=9

PhilS · November 2010

Re: Normally Open Pressure Switch

JR Hill wrote: »

Thx Phil, that's what I will do then. And thanks for taking time to snap the pix. So you just installed a COTS pressure switch and use it to toggle the RS relay? What'd you use for the relay power supply? Tap off one of the 12v batteries?
Best,
JRHill

The pic was posted before to show how I was able to use the box from a BZ charge controller, since that thing was a POS (you can search my previous posts if you want to learn more). But the pic was still here so it worked out good to show you how I made the CU200 work with my system.

I can pretty easily retrace my steps to give an exact answer but I used a 120V relay, drawing power from the CU200. I KNOW I didn't make any connections to 12V for anything related to this. The only wiring is between the CU200, the relay, the pressure switch, and the plug that goes from the CU200 to whatever receptacle I want (whichever of 3 different inverters or a generator, pic is of the "inverter selection" option, with another plug for the generator above and out of sight).

I configured this pump controller to run off 120V. I understand that there are other options but with four different sources for 120V I didn't think it necessary to make provisions for anything else.

I could draw a schematic this weekend if you need... the problem would be figuring out how to make it something I could post here (it'd be EASY to draw and mail to you

)

Phil

JR Hill · November 2010

Re: Normally Open Pressure Switch

Got it, thx Phil. RS had a tiny 5 amp 12 vdc relay that I can put in the CU200. The schematic is not necessary but thx for the offer.

And thanks to everyone for the references/links to various pressure switches. I wanted to stay with the style of switch used on well and compressor type applications since the minimum and maximum set points are adjustable within a range.

All the best,
JRH

Normally Open Pressure Switch

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