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  • Totally stumped!!

    Here's the problem: Customer sometimes gets hot water at the fixtures, sometimes not. There's no rhyme or reason to when it'll happen. You'll have the hot water on and cold will be coming out and all of the sudden you have hot water for 15-30 seconds (approx) then cold again. The water pressure is good and stays the same no matter what the temperature is.

    The house is 10 yrs old with original waterheater and insulated supply lines. The lines (pex) and heater (50gal/electric) in both in the attic. 16" off the heater the water is 128' F(measured w/ my fluke 16 and pipe clamp probe). I let the water run for 30 min and the most it dropped was 124'F(I stayed in the attic and the customer said he is still getting cold water). We did this in the bathroom sink, shower, kitchen sink. Same result.

    I dissconected the hot water riser from the sink and turned the flow on at the angle stop and measured the water temp. The average was 84' F with a spike up to 125ish for a second. There's nothing in line to obstruct the temperature or pressure. You have the water heater then the fixture. Nothing in between. I told the guy I was stumped and he called 2 different plumbers.

    The 2 plumbers both say they're not sure either but they "know" that a new water heater and total repiping of his lines will solve the problem. I was there for 2 hrs and the others were there for 1hr total. One guy wants to do this for 6g's the other for 5500. I gave him my price at WAY less but I don't like selling a customer something he might not need. I swear I'm not making this up. Any ideas?
    Buy cheap, buy twice.

  • #2
    Re: Totally stumped!!

    sometimes the tub/shower mixing valve gets debris in the cartridge causing crossover?

    Comment


    • #3
      Re: Totally stumped!!

      does the homeowner know when the problem started?

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      • #4
        Re: Totally stumped!!

        It's at all the fixtures and that's why I took off the riser to eliminate the mixing valves. Didn't do this for the shower but did measure the pipe temp on the hot side and same result.

        This started all of the sudden about 2 days ago.
        Buy cheap, buy twice.

        Comment


        • #5
          Re: Totally stumped!!

          Originally posted by gear junkie View Post
          It's at all the fixtures and that's why I took off the riser to eliminate the mixing valves. Didn't do this for the shower but did measure the pipe temp on the hot side and same result.

          This started all of the sudden about 2 days ago.
          This is going to be a fun one

          does this house have recirc system or anything that would require a check valve,I'm sure all this has crossed your mind.What could someone have put in an innexesible area that has failed.
          Last edited by drtyhands; 04-11-2007, 12:04 AM. Reason: add

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          • #6
            Re: Totally stumped!!

            10 years old could be a dip tube issue.

            rick.
            phoebe it is

            Comment


            • #7
              Re: Totally stumped!!

              how does one check dip tube,do you just connect a hose to hot water outlet of tank?

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              • #8
                Re: Totally stumped!!

                If the tank is 124° F after running for 30 min can it still be a dip tube problem? What if you shut off the valve for the hot water tank then open the angle stop at the sink where you were testing. You will likely have cold water flow. Follow the pipes best as possible (in basement etc) tracing the hot water pipe that is now rather cold with the cold water flowing back to the offending crossover point. You should be able to tell the point because the cold water pipe will be the same temp as the hot water pipe. Points where the cold water tees off the main should be warmer to the touch if no water is flowing through them due to ambient warming.
                You could also try rotating from hot to cold and on/off any single handled taps to see if the flow is eliminated. Washing machine mixing valves are also suspect.
                Last edited by wbrooks; 04-11-2007, 08:04 AM.

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                • #9
                  Re: Totally stumped!!

                  Is there a hose hooked up to both hot and cold and left on? Could be to get warm water for washing a car, could be a "Y" hose on a washing machine. Anything that can create a crossover can do it.

                  Comment


                  • #10
                    Re: Totally stumped!!

                    mixing valves from hand held sprayers, sometimes have a port that are capped off and will mix in that position if turned to that spot.

                    do the tub and shower valvs have integral stops. try shutting them off and see what happens. moen valves were nortorious for mixing without leaking. this only affects the brass cartridges. not the plastic magnum cartridges.

                    i dip tube issue will give you hot water for a very short period, depending on how far rotted the tube is, or if it fell off. the simplest test is to disconnect the outlet of the heater/ hot. connect the tank to a hose to allow for quick piping to a 5 gallon bucket. you should be able to get approx. 70% of the water above 100 degrees. 50 gal. tank = 35 gallons of 100 plus water.

                    make sure to do this test after the heater has cycled. also double check both upper and lower thermostats and elements on the tank to make sure both are working. an electric heater with only 1 element or thermostat working will give you similar symptoms. the heater thermostat alternates the upper and lower element. 50% of the time it heats the top element, 50% the lower. if the lower element is bad, you will get minimal hot water.

                    still sounds like a heater issue. repiping is not the answer. it's a heater or valve crossing issue.

                    rick.
                    phoebe it is

                    Comment


                    • #11
                      Re: Totally stumped!!

                      re-read your original post carefully. 2 days ago this started.

                      what changed?

                      do the water heater test i told you.

                      you should get 35 gallons of hot out. also take off both covers to access the thermostats and elements. test for proper operation and amp draw.



                      repiping is not the answer, unless someone did something 2 days ago to really screw this up. still repiping is not going to change anything.

                      a new heater, probably. double check the mixing valves for crossing and isolate them if possible.

                      there is an answer

                      rick.

                      ps. this house doesn't have wheels, does it

                      the old timers know what i'm referring to
                      phoebe it is

                      Comment


                      • #12
                        Re: Totally stumped!!

                        Originally posted by wbrooks View Post
                        If the tank is 124° F after running for 30 min can it still be a dip tube problem? What if you shut off the valve for the hot water tank then open the angle stop at the sink where you were testing. You will likely have cold water flow. Follow the pipes best as possible (in basement etc) tracing the hot water pipe that is now rather cold with the cold water flowing back to the offending crossover point. You should be able to tell the point because the cold water pipe will be the same temp as the hot water pipe. Points where the cold water tees off the main should be warmer to the touch if no water is flowing through them due to ambient warming.
                        You could also try rotating from hot to cold and on/off any single handled taps to see if the flow is eliminated. Washing machine mixing valves are also suspect.
                        Luck would have it: Brooks is here with his years of plumbing experience. Sit down Rick, obviously your years of experience were wasted. I guess guys like us wasted our time learning a trade.
                        Last edited by plumbdog10; 04-11-2007, 10:25 PM.
                        the dog

                        Comment


                        • #13
                          Re: Totally stumped!!

                          Originally posted by plumbdog10 View Post
                          Luck would have it: Brooks is here with his years of plumbing experience. Sit down Rick, obviously your years of experience were wasted. I guess guys like us wasted our time learning a trade.
                          Still having trouble with your "people skills" dog ? What's wrong wife out of milk bone for ya?

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                          • #14
                            Re: Totally stumped!!

                            can't we all just get along??
                            9/11/01, never forget.

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                            • #15
                              Re: Totally stumped!!

                              I thought about testing the heater elements and all that but figured to cut to the chase by measuring the end result; the water temp and it seems to be good(30min and more of continuos hot water). I concede I never actually checked total volume. I'll give that a shot. The run from the heater to the furthest fixture is roughly 30 feet away. The pipe is almost totally covered by insulation(the fluffy attic type). The rafters are only 2x6's with a decoritive plaster ceiling and I weigh 260 so not too comfortable tracing back pipe to check temp that way.

                              I took the mixing valves out of the equation by taking the riser off the faucet. I never did check the washing machine. Could the washing machine cause a cross over(good thought Big Thom)? The faucets don't have intergral stops.

                              On a side note: 3months ago a guy has no hot water but all fixtures are single handle. He calls plumber A and gets sold a water heater for 1300. Still no hot water. He gets referred to me and I notice a leaking angle stop. As soon as I cut the bad one out all kinds of plastic come pouring out(hot side). Turns out the dip tube was partially disenergrated and was clogging all the fixtures. Since he had single handle fixtures he wasn't just turning on the hot water and that's why his pressure was not affected. Nice guy but not the smartest but plumber A didn't catch it either. I changed the other angle stops and rebuilt the shower mv and we're in business. Something to share in case anyone else runs into a similar problem.

                              Thanks for all the help and I'll post the result as soon as I get this done.
                              Buy cheap, buy twice.

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