Grundfos Pump Protector

Discussion in 'Pumps and Tanks Well Forum & Blog' started by kminnich, Mar 1, 2012.

  1. kminnich

    kminnich New Member

    Can someone please help me? I am trying to figure out how to integrate a Grundfos MP-204 Pump Protector into my well pump system.
    My system uses a Grundfos 16250-38 single phase pump connected to a Grundfos SA-SPM5 Control Box which, of course connects to a 40/60 pressure switch.
    I have attached a a schematic of how my system is currently laid out along with the link to the manual for the pump protector. Page six and page ten of the manual seem to be where I need to be focused but I will be darned if I can figure out how the pump protector fits in.
    Any help is greatly appreciated.

    Thank you

    link to Protector manual is :$File/L-MP-TL-001%20.pdf

    Attached Files:

  2. valveman

    valveman Moderator Staff Member

    Lubbock, Texas
    My first question is where is you professional pump installer?

    “Service and installation should be performed by an authorized service
    representative.” Grundfos

    That pump is made for a well that is around 900’ deep. So a pump installer must have installed the pump. Only the basic functions can be set on that unit without the specialized remote that most Grundfos installers are required to have.

    So my next questions is what are you trying to protect the pump from? There are much easier ways to protect from dry run or rapid cycle conditions.

    There are also easier ways to protect from voltage problems, if that is your goal.

    My experience with pump protectors is the more things it protects from, the more nuisance trips you will have. Voltage is rarely a problem with single phase pumps, and phase unbalance is only for three phase pumps. Usually protection from dry run or rapid cycling is all that is needed, and eliminates a lot of nuisance trips that leave you out of water.

    If you can’t get any help from your installer, I will read that manual and try to help you out.
  3. kminnich

    kminnich New Member

    I fired my well driller after he screwed me out of an additional $4000.00 on my drilling contract and then proceed to charge me over fifty percent markup on the well parts. At that point, I was so angry; I decided to do it myself.
    Manufactures always claim that there product SHOULD be installed by an authorized service represented. But, I have been around long enough to know if you want something done right—do it yourself. A crew of four guys and me will be lowering that pump into the ground tomorrow. Through months of research and talking to installers I believe we have come up with a solid plan—tomorrow will tell. By the way the well is 520 feet deep; I plan to set the pump at 460 feet. I am using 1.5 inch schedule 120 with galvanized couplings; the first and last 20 feet of drop pipe will be galvanized. I am using #4 wires to the service panel, check valves every 100 feet, two torque arrestors, and 1/2inch poly rope attached to the pump in case it decides to break away.
    A certified electrician is doing the entire electrical but we just can’t figure out where the MP204 gets its power from. We do know that the neutral and the phase wires going from the control box are passed through the appropriate ports of the MP-204 (appears to be some sort of sensors that use induction). I am thinking that the supply (L1/N, L2/L) are taken from L1 and L2 of the control box but am not sure. If you can help it would be greatly appreciated.
    I also realize that the MP-204 is a bit of overkill for my application, but the difference in cost was not substantial enough for me to have various different types of devices monitoring my system. The whole system is Grundfos which seems to make sense to me. I have attached a drawing of what I think (hope it makes sense).
    Thanks for your help
    LCBTL002 Control Box-2 copy.jpg
  4. valveman

    valveman Moderator Staff Member

    Lubbock, Texas
    Yes I believe you are right that it gets its power from L1 to L1n and L2 to L2L the same as the motor control box. It is not the cost but the complicated nature of the device that will cause you problems.

    That pump is designed to work at no less than 600'. Even at 460' it will run on upthrust which can destroy the pump. For that depth you would be better off with a 3HP, 16S30-24.

    I am sorry you had problems with the installer. I wish you luck installing such a deep pump. I don't like torque arrestors or rope in a well. Either of those could be a reason you can't get the pump out of the well next time it is needed. And don't use pipe dope or teflon tape on PVC pipe with galv couplings. Just makes it easier for the pump to unscrew itself. Check valves every 100' also not a good idea.
  5. Technophile

    Technophile New Member

    Duvall, WA
    Replaces the control box? Very confusing diagram.

    My, that IS a cryptic manual.
    The MP-204 looks like it is designed to be part of an industrial control system AND work with external parts. This allows detailed monitoring and more flexibility in an industrial setting, where a pump failure might take down an industrial plant at $xxx,xxx / hour. Not sure it's suited to your needs.
    Looks like the existing control box should only be used to provide the motor run capacitor, plus starter relay and motor start capacitor if needed. Maybe an external contactor ("trip relay") as well. Otherwise the MP-204 IS the control box. I think.
    The portion I was able to figure out:
    1. Instead of showing the control box as a box-with-terminals, try drawing its detailed schematic, then match it up with Figure 11 from the Grundfos manual.
    2. Looking at the diagram from your original post: feed 230V power (from before the pressure switch) to the MP-204 L1, L2 terminals. You want the MP-204 to remain powered up and talking.
    3. Connect the two outputs of the pressure switch (K1 in the Grundfos diagram) to the MP-204 I1, I2 terminals. If the pressure switch drives a contactor (if it won't take the full motor current by itself), the contactor is K1 so you hook up to the contactor outputs instead.
    4. Connect the motor to the MP-204 I1, I2, I3 terminals.
    5. Connect the motor-run capacitor in the control box: one side to I2, other side to I3 AND to L3.
    6. IF your pump uses a motor-start capacitor (seems unlikely), hook it up per the Grundfos Figure 11.
    7. Connect MP-204 terminal FE to ground (grounding rod) per Figure 11.
    8. Connect MP-204 terminals T1 and T2 together per Figure 11.
    9. You probably don't have a thermistor so just leave the MP-204 '+' terminal open. Connect the two 'C' terminals together per page 7.

    NOW, the portion I was NOT able to figure out (better call someone at Grundfos tech support!):
    1. If the MP-204 figures out that something is wrong, how does it turn off the motor? So maybe K1 (above) should actually be the trip relay contacts, OR the trip-relay contacts in series with the pressure switch, and you will need an external relay (or contactor) rated for your pump motor.
    2. Someone should smack their technical writer.

    Good luck!
  6. kminnich

    kminnich New Member

    Status Report!
    Well, my crew and I were going at a steady pace dropping 20' every five minutes. Everything was going as planned when the cable dropping the system unraveled at its connecting point to the drop pipe--we were 80 feet from being done! The system started plunging towards the center of the earth faster than an Indy 500 car (at least it seemed that way). One of my crew had the sense to grab the safety rope attached to the pump and cinched it! The pump, drop pipe, wire, and a sound tube stopped at about 500 feet--twenty feet more and it would have hit bottom! When the safety rope was cinched, the service wire continued down the hole pretty much jamming everything so bad that we could not recover it on our own! I called a well guy who, after a disclaimer, managed to work the system back up the well. It took him about two hours which included adding the remaining 80 feet of pipe and setting the well head! It was a pretty traumatic day for me as I watched all my money crashing into the earth--but after all was said and done I would do it all over again with a closer safety check of all equipment being used.

    The well is working great Pumping lots of water with great pressure! I managed to figure out the wiring of the MP-204, which is over kill for a home well, but it serves my needs well keeping a watch on over/under voltage, over/under torque, kwh used, number of starts, and hours of operation Which brings me to my question.

    As of now, I am using a 119 gal pressure tank set at 40/60 psi. When the pressure reaches 40 psi the pump kicks in and fills the tank. The average runtime for the pump is 1.03 minutes. I understand that damage to the motor will occur if it is not allowed to run at least two minutes. Is this true and could you please explain why and how I might be able to get more run time on the pump without spending tons of money? I realize (now) that the pump I have is a bit over sized for my application and that perhaps I should have used the 3hp one but what I have is what I have. When I purchased my system the 5hp pump was rated at 19 gpm but it is actually pumping 25 gpm why is this? I think at 19 gpm it would allow the pump to long enough? Also you mention up thrust in your reply to me. What is up thrust and how do I deal with it?

    By-the -way, my system is being used quite minimally right now with about 9 starts per day running 9.5 minutes daily.
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