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  1. #1
    Join Date
    May 2006
    Location
    Nags Head North Carolina
    Posts
    258
    I am having an issue with voltage, The problem is i have taken over where I am and have (1) 370 P 250 A-E and (1)370 SS 250 A-E hot water heaters from PVI. The elemants keep blowing out after a week or so. Also the fuses keep blowing. 480 3 phase. This is happening on both units. I contacted PVI and they said to check the ground, I put my amp meter on the ground at the ground and am getting 0.28 amps this is even with the main breaker shut down at the main panel. What else can I look for? I have verified all the correct wiring and all correct fuse sizes.

  2. #2
    Join Date
    May 2004
    Posts
    12,280
    Originally posted by obx11
    I am having an issue with voltage, The problem is i have taken over where I am and have (1) 370 P 250 A-E and (1)370 SS 250 A-E hot water heaters from PVI. The elemants keep blowing out after a week or so. Also the fuses keep blowing. 480 3 phase. This is happening on both units. I contacted PVI and they said to check the ground, I put my amp meter on the ground at the ground and am getting 0.28 amps this is even with the main breaker shut down at the main panel. What else can I look for? I have verified all the correct wiring and all correct fuse sizes.
    OK.. hope I get this straight... you took an amp reading at the ground on the water heater and got an actual reading?

    I think what he meant was to check to see if you had continuity to ground and if so, if you also had resistance. Resistance would be bad also no continuity to the ground wire would be bad. You would have to run a new ground to the water heater. Don't rely on water pipe to ground your unit.

    What you took a reading of is the blown element power through the water to ground. I would also check for a few other things... they are....

    -Wild leg (one of the three power legs to ground meters much higher than the other two)

    -Water level control, if there is one, your water heater may be running out of water

    -Water fill valve, if there is one, may not be working either due to the above water level control.

    -Water level probes are dirty which are not allowing the control board to properly fill the water heater to level and exposing the elements to air. Your elements are immersion elements and should not be without water.

    I would also check the TPRV (temperature-pressure relief valve) it is leaking or blowing off and down the drain then you could have a temperature control run-a-way or the PRV is weak.

    I am not sure what you have so I tried to cover a general span of what could be wrong.

    Hope this helps




  3. #3
    Join Date
    May 2006
    Location
    Nags Head North Carolina
    Posts
    258
    No I took the reading at the main junction box where the lugs are that ties both tanks electric into them. Now I did shut the main power down from the breaker panel in the utility room. So there is no power up to the hwt room at all. The gorund is lugged to the junction box. I put my amp probe on there the ground wire and got the reading,(while the pwr is off) I'll get some pics tomorrow if it will help. Made a quick sketch

  4. #4
    Join Date
    May 2004
    Posts
    12,280
    I really don't think it is anything more than feed back from another device.

    A quarter of an amp shouldn't bother anything.


    To blow your immersion elements you either have a water level problem or a high leg. Shouldn't be anything else.



  5. #5
    Join Date
    Jan 2006
    Posts
    153
    Lusker is deff correct. You might want to check for erratic phase jumping to. Somtimes in situations, phases with jump from one to another especially in delta and will cause major problems. What size of wiring do you have? Are you getting 280 VAC in the middle leg? What KW are the elements rated? If the power is off and your still geting current to ground, you might want to check the nuetral bar in the pannel and check for proper phase grounding.
    Tell me, is your power coming from a feeder panel from main pannel? That ground in the junction is correct and is called bonding, but that bonded ground should be tied in with branch cicuit to the pannel ground/nuetral bar. You might have a short in a phase to though, take off the phase wires in the pannes and ohm all phases from the J-box to the pannel.

    [Edited by boduke on 10-23-2006 at 12:31 PM]

  6. #6
    Join Date
    Jan 2007
    Posts
    1
    Quote Originally Posted by ;1247792
    I am having an issue with voltage, The problem is i have taken over where I am and have (1) 370 P 250 A-E and (1)370 SS 250 A-E hot water heaters from PVI. The elemants keep blowing out after a week or so. Also the fuses keep blowing. 480 3 phase. This is happening on both units. I contacted PVI and they said to check the ground, I put my amp meter on the ground at the ground and am getting 0.28 amps this is even with the main breaker shut down at the main panel. What else can I look for? I have verified all the correct wiring and all correct fuse sizes.
    Did you ever figure out what was causing the problem withthe elements blowing?

  7. #7
    Join Date
    Aug 2006
    Posts
    2,609
    Had the exact same problem at General Reasearch, in Tysons Corner. The water heater was acting as a Neutral/Phase to Phase conductor for the entire kitchen. We did a clean-up turn down maintenance on all the kitchen panel. Then we got the utility involved, and the problem went away. I also got a call for no hot water a month or two later. I had 460 volts to all the elements. Had to replace all the fairly new contactors, as they had some kind of glaze on them.

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