new install where COLD is HOT

Discussion in 'Water Heater Forum, Tanks' started by EdPDX, Aug 28, 2010.

  1. EdPDX

    EdPDX New Member

    Jun 8, 2007
    Just put in a new electric water heater. The electric heater is the one rated by Consumer something as a BEST buy. Its the GE. I installed it in place of a leaky unknown brand. The COLD line was on the same side so I just lined them up and hooked them up the same.

    When I check the temp by feel, I see that the one from the COLD stub is HOT. The line attached to the HOT stub is barely warm. The supply lines are not marked, and I can't tell if one is truly coming in off the main supply.

    All I need to know is: 1: can the water heater still be supplying hot water effectively- there is hot water in all the right places in my home now.
    2: Is the current condition of my hot COLD line and room temp Hot line the norm? ...or did I cross the lines?

    p.s. The heater is in the basement.
  2. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Sep 2, 2004
    Retired Systems engineer for defense industry.
    New England
    There should be a shutoff...that's on the cold line. Occasionally, they put a shutoff on both sides, but it is much more common to only have one on the cold side. If the hot and cold are reversed, you won't get as much hot water out of the tank since you'll be drawing water from the bottom of the tank rather than the top. Normally, you pull it off the top, and there's a second heating element up there to aid in keeping that last bit hot. Also, if it came with heat traps, they are only designed to flow one direction, and while they may not stop the flow, they'll reduce it.
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  4. EdPDX

    EdPDX New Member

    Jun 8, 2007
    Can't be mixed up or all the HOT supply lines in my house would now be giving COLD water right? ... Unless they have all been wrong from the start! Hmmm anyone else' cold line hotter than the line from the HOT stub on their electric Water heater? Help me out here. I just paid over$600 for a new heater and I don't want to run it for the next 12 years in reverse.
  5. Jerome2877

    Jerome2877 In the Trades

    Aug 25, 2009
    Vancouver Island , BC
    Nope like Jim said you would still have hot water but it would be drawing it from the dip tube at the bottom of the tank. Hot water like air rises so you would have it for a while but the temperature would decrease faster than it should.
  6. hj

    hj Moderator & Master Plumber Staff Member

    Aug 31, 2004
    Cave Creek, Arizona
    Turn off the water valve on the cold side, and then open the lever on the T&P valve. If the water rushes out and keeps rushing out, your tank is connected backwards. If so, install a new valve on the "real" cold line and interchange the pipes to the heater. You should have been able to find this defect when you installed the new heater, since you could NOT have replaced it by just turning off the valve on the cold side. It has NOTHING to do with the hot and cold being reversed anywhere else in the house. Or at least it should not, although in some really bad "screw ups" it can happen.
  7. rlpenny

    rlpenny New Member

    Nov 7, 2010
    Tulsa, OK
    Our home was built in 1993 and we used our own HVAC contractor that installed a heat pump and hydronic supplemental heat (water coil) sourced from a pair of 40 gallon water heaters ("cheap man's" boilers were the contractor's words). This was an OPEN system such that potable domestic hot water flowed through the HVAC water coil. Anyway, I recall everything in the home plumbing wise being ok from Spring 1993 until winter time when the bathtub was being filled one night and the water temperature was super hot, then went cold, then would go warm and basically would not stay stable. This happened for several nights. The builder blamed my HVAC contractor and my HVAC contractor suspected the builder's plumber. The builder's plumber plumbed the entire house except that our HVAC contractor installed the two 40 gallon water heaters and connected them to the plumber supplied stub outs since they were part of the heating system.

    The final determination was that the plumber's helper (son-in-law) had stubbed out the hot/cold lines into the water heater closet BACKWARDS.

    A further inspection revealed two of our six sink/vanities were crossed. I'm reminded of this installation error when I see the X's (risers) underneath those certain sinks that were crossed and the X of pipes behind the water heaters.

    I've never checked the temperatures but I hope some of my toilets aren't using hot water.

    On a side note, fortunately for me, since my HVAC contractor was on site, the actual plumber did the soldering rather than his son-in-law (no plumbing license) as my neighbor's homes have had multiple behind the wall catastrophic fitting leaks over the years. Then again, our neighborhood typically runs 105 to 140 psi at the main shutoff. A local plumber in the area I've used showed me the high pressure and put in a pressure regulator years ago which has helped a lot prior to which we were replacing toilet fill valves much too frequently.

    I have a pressure guage with resettable MAX pressure needle and routinely see it in the 130 to 145 range. I've never seen the city side of my regulator below 95 psi in 17 years. TP pressure valves on the water heaters usually seeped after a few years as well until we got a replacement commercial sized pressure regulator with more effective bypass feature.

    The builder also insulated the hot water lines under the slab but who knows...I figure some of them are running COLD water because some of my sinks lose the temp too fast in the hot water lines.
    Last edited: Nov 7, 2010
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