[RE-wrenches] Need simple solution to reverse dry-contact logic on SQF water system

solardude97 solardude97 at yahoo.com
Sat Oct 16 13:41:12 PDT 2010


Is the pause several weeks in duration? IMHO Grundfos has a recurrence of their communication problems that occurred in 07. Within the last two weeks we have had yet another one of these setups exhibit the same failure to stop condition. It is intermittent in nature and as in 07 seems to be a result of low light conditions from solar disrupting the communication.
We explained to the customer that this was a possibility but since the storage tank had an overflow he opted to go ahead with the CU 200 as a controller. It seems there are full days the pump refuses to shut off on command as he is complaining about the mud bog he must drive through from the overflow.
For the foreseeable future I will not rely on anything to control the SQ Flex except a pressure switch that is interrupting current.
Nathan Jones
Power Source Solar
417-833-4274

On Sat Oct 16th, 2010 11:09 AM CDT Dana wrote:

>There is a pause in the CU200's switchover  it is not a
>consistent time span either.
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>Is there any one from Grundfos on the list that can comment?
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>Thanks,  Dana Orzel
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>Great Solar Works, Inc
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>E - dana at solarwork.com
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>V - 970.626.5253
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>F - 970.626.4140
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>C - 970.209.4076
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>web - www.solarwork.com
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>"Responsible Technologies for Responsible People since 1988"
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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 solardude97
>Sent: Friday, October 15, 2010 4:05 PM
>To: allan at positiveenergysolar.com;
>re-wrenches at lists.re-wrenches.org
>Subject: Re: [RE-wrenches] Need simple solution to reverse
>dry-contact logic on SQF water system
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>Allan,
>A very simple way to do this is install a float in the tank
>you are pumping to with a shutoff valve controlled by the
>float. Install a Square D pressure switch with a DC rating
>by the pump. As the float rises to full in  the tank and
>chokes off the discharge outlet the pressure in the line
>will rise and trip the pressure switch. We are using this
>method exclusively as there seems to be a glitch in the high
>frequency communication between the SQ Flex and the CU 200
>controller.  The pump is not shutting off on command from
>the controller consistently in stand alone applications. I
>am aware of  a half  dozen of these systems experiencing
>this issue.
>You might install a small pressure tank in the line to avoid
>water hammer in the system. Simple and cheap.
>Nathan Jones
>Power Source Solar Inc.
>Springfield, MO
>417-833-4274
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