[RE-wrenches] Grundfos SQ FLEX AC/DC auto switching

[Mark Dickson]

Allan, 

This is all Dwight at Genpro could tell me. . .sorry to be vague!  I agree,
it seems like it would not know the difference.  

 

I would love to shed some light, however this was shared with us at the NGWA
show by a Grundfos Engineer.  It has something to do with the thrust load
bearing on a them.  Lorentz has two I believe Grundfos has one.

 

Best regards,

 

Mark Dickson,

NABCEP Certified Solar PV Installer T

Oasis Montana Inc.

 

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From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Allan
Sindelar
Sent: Monday, May 24, 2010 2:39 PM
To: RE-wrenches
Subject: Re: [RE-wrenches] Grundfos SQ FLEX AC/DC auto switching

 

Mark,
Your message gave me pause, as I just last week specified this setup, so I
checked into it with our Grundfos rep. He said he had never heard anything
recommending against the flex in a pressure system. He said the SQF doesn't
know the difference between 40 psi and 100' of head. At the end of the day
the pump just stops. 

He did make a point of emphasizing the need for pressure relief valves, as
the helical rotor models can overpressure a system.

Could you check with your distributor about this and post the reason you're
given, please?
Allan

Allan Sindelar
 <mailto:Allan at positiveenergysolar.com> Allan at positiveenergysolar.com
NABCEP Certified Photovoltaic Installer
EE98J Journeyman Electrician
Positive Energy, Inc.
3201 Calle Marie
Santa Fe, New Mexico 87507
505 424-1112
www.positiveenergysolar.com <http://www.positiveenergysolar.com/> 



Mark Dickson wrote: 

Our Grundfos pump distributor has always warned against using the SQF pumps
in pressure pumping situations.  I can't quite remember why, but you may
want to check into that.  The Lorentz HR's have been the choice in these
situations.

 

Best regards,

 

Mark Dickson,

NABCEP Certified Solar PV Installer T

Oasis Montana Inc.

 

 

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From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Kent
Osterberg
Sent: Thursday, May 20, 2010 5:18 PM
To: RE-wrenches
Subject: Re: [RE-wrenches] Grundfos SQ FLEX AC/DC auto switching

 

Kirpal,

None of the SQFlex equipment is UL listed.  You may find that your AHJ won't
approve any of the SQFlex controls and possibly not even the pump.

Kent Osterberg
Blue Mountain Solar


Kirpal Khalsa wrote: 

Hi Folks.....I am working on putting together a domestic water pumping
system using a grundfos 11 - SQF - 2.  This system will be connected to a
standard pressure tank and cistern and have a solar array providing primary
power.  However at night and on cloudy days we would like the system to
switch back over to AC power from the grid.  I know that the grundfos IO 101
switch box allows the pump to use an AC source and when the AC source is
removed it automatically switches back to DC.  What I am looking for is when
the DC source (solar) is not available it automatically switches over to AC
power (grid) ( the reverse of what the IO 101 switch does)  and when the DC
becomes available again it again automatically switches back to the DC power
(solar).  

Has anyone done this?  Any recommendations for configuring this set up.  We
are looking to provide solar water pumping during the day both when grid is
present and when their is a power outage and AC pumping at night or cloudy
weather all without battery back up.

Thanks in advance for any advice.!

-- 
Sunny Regards,
Kirpal Khalsa
NABCEP Certified Solar PV Installer
Renewable Energy Systems
www.oregonsolarworks.com
541-218-0201 m
541-592-3958 o

 
 
 





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