Show Posts

This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.


Topics - Kent M

Pages: [1]
1
Valve Tech / CSV1A and low flow rate
« on: July 23, 2022, 08:57:13 PM »
I've had a CSV1A installed for ~ 7 years and it's been great!  It replaced the CU301 controller and pressure transducer on our 18 year old Grundfos SQE pump, turning it into an SQ pump I guess.

At the 80' pumping depth on our 130' well, that pump has been able to supply over 20 gpm at whatever pressure was asked of it...until lately.  Now if a couple sprinklers are running concurrently, the flow rate is noticeably lower than in years past and the pump is unable to maintain the pressure set on the CSV1A.  If I hook a hose up to the 3/4" spigot near the pressure tank and turn it on full, the pressure will drop enough to empty the tank and kick off the Square D M4 pressure switch.

I disassembled the CSV1A a couple days ago and it looked fine - no holes in the diaphragm, no sand packed into any of the openings, just a little iron staining that wiped off easily. It has no trouble maintaining a pressure for a low flow like a shower or two, just at higher flow rates.

Is there any type of failure in a CSV1A that would cause these symptoms?  My guess is it is not the valve, but would like to be sure before calling in the well servicing company.  Would it be possible to temporarily remove the guts of the valve and replace it with an o-ring and flat disk of sheet metal that the pressure adjusting spring and cage would hold in place?

2
Pumps, Wells, Tanks, Controls / Grundfos CU301 retired
« on: August 26, 2015, 10:01:17 PM »
I installed a new CSV1A and pressure switch today and retired the still (surprisingly) working CU301 V2 from 2003.  I bought a 60/80 switch and adjusted it to 60/75 and set the CSV1A to 70.  Everything is working as advertised.

For my own curiosity, I installed a pressure gauge upstream of the CSV1A to see what the back pressure was during pump running.  I was seeing around 155 psi.  Is that a fairly normal reading?  Kind of surprised that our 12 year old  SQE 15-250 (though I guess it's really just an SQ now) can produce that much pressure.

An interesting side note about the switch I bought:  It has a lever with labels Auto -> Start ->  Off.  Took me a while to discover that it would not run in Auto with less than 10 psi at the switch.  It's apparently a safety in case the well pipe completely ruptures.  To start from an empty pressure tank, one has to lift the switch to the Start setting to manually close the contacts until the pump builds the needed pressure for it to switch normally.

3
Pumps, Wells, Tanks, Controls / Pressure switch on-off range
« on: August 12, 2015, 04:04:51 PM »
All the factory presets I've seen are a spread of 20 psi - 20/40, 30/50, 40/60, etc.  If I went to a CSV1A, would there be a problem adjusting a 50/70 to a 60/70 setting, and running the CSV1A at, say, 65?  I have a twenty gallon tank, so the draw-down with a 10psi differential would still be a couple gallons, which should ensure enough pump run time for short usages.

Would the air pressure still be set at ~2psi below the turn on pressure for a 10 psi spread?   

4
Pumps, Wells, Tanks, Controls / Interesting Grundfos SQE Data
« on: August 12, 2015, 02:29:58 PM »
I've had a Grundfos SQE 15-250 with CU301 installed since 12-2003.  No water related problems with pump or controller, though I did have to put noise filters on the circuit to prevent interference with our X-10 system.

Being somewhat of a techno nerd, I acquired an R100 remote a few years ago to be able to read the data stored in the pump.  As of 8/10/2015, here are the numbers reported by the system, with a few estimates of my own:

Power Consumption (kWh):  1,088*
Number of Starts:  176,471
Operating Hours:  1,016
Starts Per Op. Hr.:  173.7
Starts Per Day:  41.5  (4,248 days between 12/23/2003 and 8/10/2015)
kWh Per Day:  0.26

Estimated Gallons Pumped:  609,600   
Estimated Gallons Per Start:  3.5   
Estimated Gallons Per Day:  143.5

* The R100 reports a 40W load, when the pump is off.  If that is accurate, then an additional 4,000+ kWh of electricity were used in standby mode.  I need to measure that with amp meter to verify.  Pretty sad if true.

The pump is rated at 15gpm at 287' at high speed.  Our pump is hanging at 80' in our 130' well with static at 30'.  This pump could probably do 22-23 gpm from 80'.  I've conservatively used 10 gpm in the calculation for estimated gallons, since the pump is likely never running at full speed.

It's pretty obvious that the installer didn't do any sizing calculations, but probably used this same pump for every residential job.
 
We've never had the 2 gallon tank that Grundfos suggests, but had a fairly new 36 gallon when installed and a 20 gallon replacement for that installed 4 days ago.  I imagine the number of starts would be considerably higher had we been using the 2 gallon tank.

Ok, sorry for the long winded post, but hope someone finds it useful.



Pages: [1]