electrical recirculating pump

Discussion in 'Electrical Forum discussion & Blog' started by spageddy, Sep 21, 2008.

  1. spageddy

    spageddy New Member

    OK, my dad has this recirculating pump (Grundfos UPS 20-42) that kept the hot water on demand and hot at a moments notice and when the seperate timer died, he just disconnected it and he has to wait a little longer to get hot water at the sinks further from the heater than he used to...

    Anyway, now he wants to connect a switch to it so it can be enabled at will but I'm not experienced with AC electrics (cars and PC's, that's different).

    There are 5 wires involved and I'm not confident on how they need to be connected as the options ive tried seem to blow the breaker...

    The pump has two wires, one red and one blue coming from it where the conduit/romex (what's the difference anyway?) feeds to the switchbox/housing, the ac feed offers green, grey and black wires.

    At the hardware store, the guy said the green is ground and should be affixed to the housing as well as the ground on the switch, as for the rest it he said the black was hot and the grey was common. ? it seemed then, that either the red paired with the black and the blue paired with the grey or the other way round took care of the rest. not many other options, right?

    Either the pump is bad ? or there are other options or something else, as both pairings pop the breaker after connecting and enabling the breaker and trying the switch.

    What am i missing? this seemed simple but its not responding that way.

    Advice would be appreciated, thanks in advance!

    - Spageddy

    Attached Files:

  2. Chris75

    Chris75 Electrician

    Litchfield, CT
    was the timer orginally installed in that utility box? How was the splice made before you touched it?
  3. Bill Arden

    Bill Arden Computer Programmer

    MN, USA
    The grey wire is probably a faded white wire.

    Here is how I would wire it

    House Black to switch
    House White to pump blue
    Pump red to switch.
    Green to box

    Do not connect the white to the box!

    The blue wire worries me though. It might have had a sensor or a starting cap.

    Are you sure there isn't another white wire in the pump's connector box?
    That would be the box behind your box and part of the pump.
  4. spageddy

    spageddy New Member

    elec recirc pump

    the blue and red wires seem to be the only wires from the pump, i dont see any others, even partial or broken wires coming from the pump.

    the white is/was connected to the box, kindof an extension to the green i was told to be a ground that should be connected to the housing and the ground port on the switch, bad advice i followed?

    unfortunately, I have no idea how things were originally installed, I was told the original timer died almost 10 years ago when it was removed from the box and the wires were isolated with the twist connectors... wish i had more info...

    does this help anybody?
  5. jimbo

    jimbo Plumber

    San Diego
    Are you saying the pump has been idle for 10 years? Good luck with that!
  6. hj

    hj Moderator & Master Plumber Staff Member

    Cave Creek, Arizona

    The pump did not come with pigtail wires so the colors coming from it are probably something the installer had laying around. After 10 years of disuse, the pump is probably frozen, but that should not trip the breaker. Without testing the motor circuit to see if it is shorted out, we cannot help you, because with 2 wires in and 2 out, there is no reason it should not work, regardless of the way the wires are connected, as long as the pump is functional.
  7. Schrammdriller

    Schrammdriller Pumps and well contractor for 25 years

    Angels camp, California
    My grunfos pumps freeze up every year. Open the chrome screw on the motor end, and with a penlite you will see the end of the motor rotor, it has a screwdriver slot in it. Turn the rotor in the direction of the arrows next to the cap, jog it in and out to allow water to push out, along with rust and junk that is plugging it up. If you cannot get it to turn at all, its too far gone or you would have to pullit apart to clean it. The pump will not blow a breaker with just a locked rotor. Open the pump box, you should see terminals "N" and "line" - house white to n and black to line terminals [and check your black incoming to see if it really is the hot]

    It is a wetted rotor pump - water from the system is always inside the motor, thus when it sits, stuff plugs it up, thats why they gave you the end cap to open it and flush it. This pump is a servicemans dream profit maker - good pumps that dont turn, and they can honestly say to the homeowner the pump is froze up... but just a screwdrivers twist away from new.
  8. Bill Arden

    Bill Arden Computer Programmer

    MN, USA
    Note: Grounding that white wire to the box could trip the breaker if the breaker is a GFI type.
  9. spageddy

    spageddy New Member

    electrical recirculating pump III

    thanks for all your responses, i was on holiday and just got back to checking for responses..


    The wires are all as i originally encountered aside from the change with the green wire grounding to the housing and continuing to the switch housing through an added extension, the guy @ the hardware store said that should be.... he's supposed to know more than i, i think... easy to leave out and retry and observe...

    I tried to get as close a view as possible and cannot see any other wires but the blue & red to / from the pump.

    The white wire extended from the green @ the housing was supposed to be connected to the switch ground?

    HJ - Yes, i thought the pump should end up spinning one way or the other depending on the direction of the blue / red wires? should that green wire have been left connected only to the housing and not the switch as well?

    Schrammdriller - could the wiring i mentioned above cause the blown breaker? sounds easy to verify if the thing still spins and /or I can try testing for current on those lines, i think i have a DVOM somewhere.... I'll open that pump and see if it will rotate manually as well...

    Thanks again for your suggestions
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