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Primary Pump On All The Time

Jake48
Jake48 Member Posts: 28
I have a Vitodens 100 with low loss header and I have 4 pumps, one for downstairs zone, one for upstairs zone, one for hot water superstore and then the primary pump.

I just happened to notice the primary pump is on all the time.  I know this is dumb but I don't remember if it has always been on and just didn't notice it or there is a faulty switch and now it is on all the time.

Is this supposed to be on all the time or only when the burner ignites and it is supposed to stop a few seconds after the burner runs through its cycle?

Comments

  • Zman
    Zman Member Posts: 7,103
    Only when there is a call

    I am not familiar with the Vitodens controller, but, Generally the primary circ will be on any time you have a call for heat or DHW. It will continue circulating when the boiler reaches it's target (between burner cycles) ,many will stay on a few minutes after the call  goes away (post purge). If you have a cold boiler with no call, I think your circ has a control issue.

    Carl
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • Jake48
    Jake48 Member Posts: 28
    Primary Pump On All The Time

    it sounds like it is suddenly malfuntioning and shouldn't be running all the time.  What could have caused this to happen and what is the fix?
  • CMadatMe
    CMadatMe Member Posts: 3,085
    edited June 2012
    Boiler Pump

    Should only be running on a call from DHW or Thermostat. Mind you the pump does run for 1-1/2 min after a call as a post purge. Make sure you don't have a cut in wires and it's wired right. They did remove the factory jumper on RT I hope. Can you wittier out a quick wiring diagram as to how it's wired?
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
  • Jake48
    Jake48 Member Posts: 28
    Primary Pump On All The Time

    The unit was installed about 7 years ago and talking to other family members, they don't remember it running all the time so we don't have an installation problem, it sounds like a new problem.  I will check for cut in wires.  Any other possible causes for this to suddenly start running all the time?
  • Zman
    Zman Member Posts: 7,103
    First

    First, Check the manual to be sure that the controller is indicating there is no call for heat or hot water.

    Next, follow the wire and be sure it is wired to the correct terminal, according to the manual.

    Check to see if the boiler has a setting that would leave the pump on all the time (some systems may be set up this way).

    After that, I would call tech support or wait for a response from a "wall" member that works on these regularly.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • CMadatMe
    CMadatMe Member Posts: 3,085
    edited June 2012
    WB1A

    This a very basic control. There has to be a call for the boiler pump to come on. Either cut wire and it's arching or PPM board is bad. This boiler did not come outdoor reset standard so there is no warm weather shut down. Nothing

    in between unless you have a Como-OT communicating with the boiler. Is the domestic tank satisfied? Check that wiring also.
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
  • Jake48
    Jake48 Member Posts: 28
    Pirmary Pump On All The Time

    No cut wire and no sign of arcing.  Hot water demand is fine.  someone took a shower a while ago and that hot water pump came on and then off after a couple of minutes.  The primary pump is on all the time.  Are installations ever done to have the primary pump on all the time or would that never be the correct way to set up the system?
  • Jake48
    Jake48 Member Posts: 28
    Primary Pump On All The Time

    By the way as you all know the other 3 pumps (upstairs zone, downstairs zone and indirect hot water) are all controlled by thermostats.  What controls the primary pump's on and off is it temperature or pressure or something else.

    The reason I ask is the unit's digital display say pressure is 10 PSI and the gage says 15 PSI.  Is it possible this difference is causing the pump to stay on all the time?
  • CMadatMe
    CMadatMe Member Posts: 3,085
    edited June 2012
    Disconnect

    The wires going to RT and DHW. If the pump still runs, bad ppm board. There are no control functions that tell the pump to run all the time. If the pump terminal is seeing 120 volts to run that pump its a bad relay in the ppm board.
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
  • CMadatMe
    CMadatMe Member Posts: 3,085
    Dip Switch

    make sure dip switch S1 is in the off position.
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
  • Jake48
    Jake48 Member Posts: 28
    Primary Pump On All The Time

    Chris I think you may be on to it.  I looked at the vitodens Electrical wiring for the S1 dipstick (which I have attached).  If you look at the bottom right of the page it appears to me that you can use the S1 to set the pump to cycle or be on continuously.  Chris, am I reading that box correct?

    Now, when I opened the electrical panel on the unit and looked at S1, it looks exactly like the figure for S1 on the bottom left of the attached page.  Meaning 1 through 4 on the S1 are in the "on" position.  According to the box on the lower right, the on position is supposed to have the pump cycle off 10 minutes after the purge is finished.  Chris am I reading this correct?
  • Jake48
    Jake48 Member Posts: 28
    Primary Pump On All The Time

    PS when I look at the actual electrical panel, the S1 1-4 are not all quite on the bottom as shown on the attached electrical digaram.  Meaning the black lines on 1-4 of S1 are not on the bottom, they are up a little off the bottom.  Don't know if this means anything
  • CMadatMe
    CMadatMe Member Posts: 3,085
    Make Sure

    Dip switches are all in the factory position, then reset the boiler.
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
  • Jake48
    Jake48 Member Posts: 28
    Primary Pump On All The Time

    Chris, yes they are all in the factory position.  So I just moved up the S1 to the top to turn it "on".  I left S2, S3 and S4 all in the factory set down postion which is the "off".  Now according to the table in the right lower corner of the attachment the S1 being up is the"on" position will cause the pump to cycle properly.  So 10 minutes from now that pump should shut off.  I will let you know if that worked.
  • Tim McElwain
    Tim McElwain Member Posts: 4,487
    Try looking at

    dip switches for pump settings one may be set incorrectly.
  • Jake48
    Jake48 Member Posts: 28
    edited June 2012
    Primary Pump On All The Time

    Yes and I changed the S1 to the position such that the pump should cycle off and not be on all the time and guess what?  It still stays on all the time.  Very frustrating.  The only difference is when I turn off power completely then turn it back on, the pump does shut off and stays off like it is supposed to.  Then when the boiler fires on the pump starts up like it should but it doesn't shut off 10 minutes after the burner turns off, it just stay on indefinitely.  Very frustrating.  I give up.  I have decided that I will just leave it on continuously (like it probably has been for the past 5 years) and pay a little extra in electricity rather than pay an electrician 100 bucks an hours to troubleshoot it and start replacing PM and other expensive parts and have it still not fixed.  Even if he fixes it, the repair cost will be way more than the electricity cost and would take years to pay for itself.  Also note the Viessmann factory setting is set for the pump to be on continuously (see above electical diagram) so maybe this is what the manufacturer thinks is ideal.
  • CMadatMe
    CMadatMe Member Posts: 3,085
    Reset

    Reset it don't turn it on then off.
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
  • Jake48
    Jake48 Member Posts: 28
    Primary Pump On All The Time

    Ok Chris I think I tried that and it didn't work, but will try again.
This discussion has been closed.