Incoming cold pipes are hot


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Old 02-07-05, 02:01 PM
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Incoming cold pipes are hot

The main water supply pipe comes in from the street, through the main shutoff valve and splits off (for the house's main cold supply, I guess) just before it goes into the top of my water heater. Well, "cold water" pipes within probably 4 feet of the water heater are hot. And, the other pipe coming out of the top of the w/h is hot too. ?! Is there a one way valve or something that's bad? And, how can I be absolutely sure which pipe is supposed to be hot and which is supposed to be cold?...thinking that maybe someone plumbed this thing backwards or something. It's an 80 gallon, electric unit and there's plenty of hotwater. At one time, it appears that the basement flooded and there are sediment rings 30" up the side of the w/h.

Thoughts?
 
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Old 02-07-05, 02:31 PM
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Check at home depot and lowes. One way to go is they have check valves that go on the cold water and also on the hot water to stop this. they only open when you use hot water.There also are copper loops like or traps like that you can put on the lines that will stop it. Its just the hot water trying to go up the pipe is all and the cold water comeing down. The tank should be marked hot and cold. Turn a hot water valve on and feel the pipes as the water runs. The dip tube has to be in the cold water.

ED
 
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Old 02-07-05, 05:03 PM
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You are describing thermal expansion to a tee.


Any home in any town, any state will have this occurrence. Hot water creates thermal expansion, the water is backing out of the tank.



Sounds like you need a Thermal Expansion Tank








Goes between the cold water inlet of the tank and the shutoff valve.


Thermal Expansion can cause numerous problems due to pressure, and can rob a PRV in the main line of its protection. A closed system has no way to remove added pressure caused by thermal expansion, short of someone opening a valve, flushing a toilet, running a faucet.



Check into it.
 
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Old 02-08-05, 09:09 AM
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Thanks, guys. By "closed system", do you mean one without a PRV? Is the PRV the valve on top of the w/h? The one that's there looks ok, but how to know for sure? Or, do you mean another valve that regulates incoming pressure? I don't have one of those and the city water pressure is strong.

so, the little blue tank works better than a check valve? From the pic, I can't see how the little blue tank would stop hot water from going back up the incoming pipe, unless there's some one way valve stuff going on? Man, that sure is a neat and clean plumbing install...you should see mine in the crawlspace. LOL
 
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Old 02-08-05, 09:50 AM
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For the cost try the check valves first or the traps next. We dont have to have an expansion tank here for the hot water . For sure some places do need it.If they have a check valve in the outside water line so it cant siphon the water. I think what you have is just like an old hot water boiler with out a pump. Its not thermal expansion.The hot water will go up a pipe and the cold water will come down is all just by hot goes up and cold comes down.

ED
 
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Old 02-11-05, 05:51 AM
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Not to hijack the thread but how big an expansion tank for a 40 gallon heater?
 
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Old 02-11-05, 06:44 AM
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If you dont have a check valve or so called anti siphon valve in the water line to the home. Why would you need an expansion tank on the water heater.

ED
 
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Old 02-11-05, 07:35 AM
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Because my T&P valve keeps leaking and that is what I figured would solve the issue, sinc ethe temp seems fine and I can't find any
 
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Old 02-11-05, 10:59 AM
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Terricksa,



First, check your water pressure with a pressure gauge like the one shown below




At night when no one is using water in the home, leave this gauge on and check the pressure when the T&P starts to leak. If the pressure is high, thermal expansion is the problem.



If the pressure is not significant, then just the T&P needs replacement, A under $10 ticket item.



2.5 gallon expansion tank is all you should need for any water heater under 65 gallons.


Here is an image of one





You would need the smaller of the two.


Installing a thermal expansion tank always provides protection, so the investment is well worth the effort.


Just make sure that you are correctly diagnosing the problem.
 
  #10  
Old 02-19-05, 08:36 PM
sharonlee_in_pa
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Help

you see that "blue expansion tank" in the picture? Can whoever took the picture please tell me what is written on the label on the tank? I'm having a small dispute with a contractor who recently replaced my "blue" expansion tank with a different one (the new one is white, it is smaller -- Amtrol). However, the contractor SWEARS this white one is the SAME EXACT tank as previously installed, except that this one is painted white.

I would sure appreciate it if you could provide me with the model number and mfr name of the blue tank. Or better yet, a close up picture of it. Many thanks

sharonleeinpa@aol.com
2/19/05
 
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Old 02-20-05, 10:56 AM
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Karen,

My new heater came with (2) two foot sections of that round foam insulation, one for each line. All it says in the book is..."Make sure that the insulation is against the top cover of the heater."

That, and the check valve nipples like Ed mentioned, might save you a few pennies.

Lets Go #24 !!
 
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Old 02-20-05, 12:40 PM
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http://www.r2000manitoba.com/hot_wat...#energy_losses


This should tell you what and how the traps or check valves work on top of a water heater.
On the tanks dont know the color. But An Extrol tank is for a boiler set up .The one for potable water heaters is a Therm-X-Trol.

ED
 
 

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