Author Topic: Want to replace VFD with CSV setup...but have some questions  (Read 1887 times)

smarty39

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Want to replace VFD with CSV setup...but have some questions
« on: August 22, 2022, 04:11:29 PM »
Hi there,

Found this great product (and forum) after searching for Franklin Monodrive replacements.  I have just had my 2nd VFD fail (original Franklin unit and now this 'newer' Monodrive) after only 12 years total...so at this point I am refusing to purchase another one and would like to instead convert to a CSV setup.

My biggest question is in regards to the pump.  I unfortunately do not have any records as to what type of pump is in there now other than I do know it is a submersible style.  On the current, faulty Monodrive it shows the dipsticks for both the pump and motor as 1hp, so I'm going to assume that is correct since it worked perfect...before it died again.  I am also goin to assume that it is a 3-phase pump due to the VFD being installed in the first place...am I right in concluding that I will need a new, single-phase pump even if the current pump is still functional?  If so, what pump is recommended for a ~30ft deep well that is located directly beside the house (only an additional 30-ish feet from the well casing to the mechanical room).

I always had ~70psi which I would like to keep, and that is what the Monodrive was set at as well.  We have a fairly large (4 zone) in-ground irrigation system that ran fine with the current setup so I'm hoping nothing would need to change there.  The existing pressure tank appears to be okay, but I'm wondering if I should just bite the bullet and replace everything to start fresh.  At the end of the day it would still be cheaper than just a new VFD unit which is crazy.

Sorry for all the questions but being in Canada I need to be sure as to what I'm ordering as returning would not be cheap or easy.  I've read a ton of posts on this forum but everyone has their own specific scenarios...and I don't see much discussion regarding the pump side of things and what brands/models are being used.

Thank you very much in advance!  I've attached a couple pictures of my current setup for reference.
« Last Edit: August 22, 2022, 04:13:28 PM by smarty39 »

Cary Austin

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Re: Want to replace VFD with CSV setup...but have some questions
« Reply #1 on: August 23, 2022, 06:50:51 AM »
Fortunately the "mono" in monodrive means you have a single phase motor.  All you need is to replace the Monodrive with a standard capacitor start 2HP control box, and the transducer with a regular 60/80 pressure switch.  Then adding a CSV1A Cycle Stop Valve set at 70 PSI before the first tee and/or the pressure tank/pressure switch will give you strong 70 PSI constant pressure.  Since this is working at 60 to 80 pressure, I would use at least a 10 gallon size pressure tank as comes in the PK1A complete kit.  You can get the PK1A kit with a 10 gallon tank, a 60/80 heavy duty pressure switch, and it has a pressure relief valve and everything else you need to control that pump.

smarty39

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Re: Want to replace VFD with CSV setup...but have some questions
« Reply #2 on: August 23, 2022, 09:33:40 AM »
Thank you for the reply, Cary.

I'm a little bit more confused now though.  You say to replace the monodrive with a 'standard capacitor start 2HP control box'...does that mean that I still need a control box even though I want to switch to the CSV?  I thought I could do away with a controller all together, or have I overlooked something?  I was under the impression that I could purchase the full kit from you (CSV, tank, switch, etc) and slap that in, rip the controller off the wall, and be good to go?  Also, is there a way to confirm that my pump is a 100% a single phase motor?  Everything I've read talks about 3 wires for single phase...but mine has 4 going into the Monodrive as you can see in the photo...

I was finally able to speak with a local well guy this morning and he basically said the same thing...replace the Monodrive (as he has no idea when he could get one) with a basic control box and put a new pressure switch in, but he thinks I would need a much bigger pressure tank for it to work.

Finally, how would I go about confirming that A) my pump working properly still, and B) it is in fact a 1HP unit?

Thank you again for the assistance, I will place an order as soon as I know my pump is good!
« Last Edit: August 23, 2022, 10:17:07 AM by smarty39 »

Cary Austin

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Re: Want to replace VFD with CSV setup...but have some questions
« Reply #3 on: August 23, 2022, 12:00:47 PM »
Sorry I meant 1HP control box like this one.
https://www.grainger.com/search/pumps/well-pumps-systems/submersible-deep-well-pumps-motors-heads/submersible-deep-well-pump-motor-control-panels?tv_optin=true&searchQuery=franklin+control+box&tier=Not+Applicable&gucid=N%3AN%3APS%3APaid%3AGGL%3ACSM-2296%3AYRB941%3A20500731&gclid=Cj0KCQjw9ZGYBhCEARIsAEUXITX9R6KBb83yXC2cu3qvVp14_cZxBDBJYVwvpg5bmwG2WfcSIWwCcjYaAsuVEALw_wcB

You have 4 wire coming up, which means a 3 wire single phase motor with ground.  So, you will need the standard control box, but it is completely different than the Monodrive box.  If it was a 2 wire motor with ground no control box is needed, but those 2 wire pumps won't work with a Monodrive. You will need the control box to tell if your pump is still good.  If so, then all you need is the PK1A with a 10 gallon tank and a 60/80 pressure switch.

smarty39

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Re: Want to replace VFD with CSV setup...but have some questions
« Reply #4 on: August 23, 2022, 12:23:58 PM »
Okay, thanks...that's where I was confused then.  So no matter what, I will need a control box, correct?  So the pump will get wired directly to the control box and then the new pressure switch wiring connects to the control box as well?  Basically I am swapping a 'dumb' control box with less brains with the overly-complex Monodrive?

If I put a new pump in, should I put another 3-wire in or just use a 2-wire and simply not hook up the 2 other wires?

I'm sure I'm overcomplicating this but I'm trying to make sure I have all my ducks in a row.  The current pump is 12 years old so even if it's 'okay', I'm sure it won't last much longer with our rusty ground water.  I will likely replace the pump regardless so I'd like to know the best way to incorporate the CSV system ahead of time.  If I can go with a 2-wire pump and not need a control box at all then I will do that.  But if the 3-wire pumps are better for some reason, I will replace with the same, current pump and then add a new control box.

Thanks again for all the help!

Cary Austin

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Re: Want to replace VFD with CSV setup...but have some questions
« Reply #5 on: August 23, 2022, 04:33:02 PM »
Not much difference in 2 wire and 3 wire for a 1HP.  But I prefer 3 wire as it has more starting torque and has less components in the motor.  The 3 wire motor with a control box should also cost about the same as a 2 wire without a control box.  But it is really just a matter of preference as there are others who prefer 2 wire motors.  But you will need a control box to see if your pump is still good.  If not, then just buy a new 3 wire motor as you already have the control box.