Cold water supply through water heater?

16 Replies

We had a recent repipe done by not a great contractor (not my choice, long story).  They failed to strap the pipes so now there is major rattling and pipe contraction noise in the walls where there didn't use to be.  But my biggest concern is that any use of the cold supply at any faucet and the toilet generates fill action in the water heater.  Why would all the cold supply be going through the heater causing it to refill?  I'm so confused.

Kristine Marie Poe They may have reversed the hot & cold.  Was this a licensed plumber?  It also sounds like you're going to have to go back in and secure the pipes properly.  Were permits pulled?  

Good luck with it all. 

What is "fill action" in the water heater?  A water heater would normally be filled all the time.    

If you leave the cold water faucet open - does the water coming out ever get hot?

Try this:  turn on a cold water faucet - then listen for the "fill action" sound - and then turn off the circuit breaker to the water heater.  Please note if the "fill action" sound stops when the breaker is turned off.  Let me know what happens.

stephen
---------------


Originally posted by Kristine Marie Poe:

We had a recent repipe done by not a great contractor (not my choice, long story).  They failed to strap the pipes so now there is major rattling and pipe contraction noise in the walls where there didn't use to be.  But my biggest concern is that any use of the cold supply at any faucet and the toilet generates fill action in the water heater.  Why would all the cold supply be going through the heater causing it to refill?  I'm so confused.

That sounds incredible!! I can help you with the rattling noise.

I would get some spray foam and fill the space with a can. You will require a small hole. but it can easier be patched. It beats the rattling.

Good luck!!

So what happened Ms. Poe ? 

Originally posted by @Stephen S. :

So what happened Ms. Poe ? 

 So I think I didn't explain correctly.  I shouldn't have said I was hearing fill action. What I'm hearing is the noise from mixing the hot and cold water in the tank (an old tank with a lot of sediment that bangs and gurgles when cold water enters and mixes with hot water).  The issue I'm having is that that I'm hearing that noise when the toilet flushes and not hot water faucets are being used. No hot water should be leaving the tank for a toilet flush, correct?

Originally posted by @Dave Fontana:

That sounds incredible!! I can help you with the rattling noise.

I would get some spray foam and fill the space with a can. You will require a small hole. but it can easier be patched. It beats the rattling.

Good luck!!

Good idea.  The spray foam might be the solution.  There is an ongoing temp. change noise (creaking/clanging) in the new copper pipe in the wall near the water heater.  And there is the mother of all rattles where one of the supply pipes near the floor and exits under the house.  The wall is the original 1920s plaster and lath, now with huge replacement patches (as in half the entire wall).  If I can pinpoint the locations, a few holes to spray in the foam would be worth it.

Marie,

Sure.  How old is the house?  It used to be a standard construction item  (in the days before central A/C became common)  to supply toilets with hot water for flushing.

stephen
-----------------------



Originally posted by Kristine Marie Poe:
Originally posted by @Stephen S.:

So what happened Ms. Poe ? 

 So I think I didn't explain correctly.  I shouldn't have said I was hearing fill action. What I'm hearing is the noise from mixing the hot and cold water in the tank (an old tank with a lot of sediment that bangs and gurgles when cold water enters and mixes with hot water).  The issue I'm having is that that I'm hearing that noise when the toilet flushes and not hot water faucets are being used. No hot water should be leaving the tank for a toilet flush, correct?

Is there a recirculation system?  That may play a role.

Another possibility is you have some sort of a cross over between hot and cold.  Basically any SINGLE lever system - shower, kitchen/bar/lav faucet with a single lever there is a mixing valve, if the mixer fails or leaks, allowing hot to enter even when you turn the lever to cold, could trigger consumption of hot water.  When you flush the toilet, cold water goes to the toilet, and hot water may cross into the cold water pipe through the leaky mixer in a nearby faucet.

I would turn all the stop valves off, then test the system.

Marie,

Did you flush the toilet enough times to get hot water to it?  As I said before:  it was very common to supply hot water to toilets at one time.  This was to keep the toilet tanks from sweating in hot humid weather and ruining the floor under them.

stephen
-----------------


 Originally posted by Kristine Marie Poe:

We had a recent repipe done by not a great contractor (not my choice, long story).  They failed to strap the pipes so now there is major rattling and pipe contraction noise in the walls where there didn't use to be.  But my biggest concern is that any use of the cold supply at any faucet and the toilet generates fill action in the water heater.  Why would all the cold supply be going through the heater causing it to refill?  I'm so confused.

Stephen is right. Flush the toilet enough times to make sure the hot is or isn't connected to the toilet. Also, does the system have an expansion tank? And if so, how old is it?
There are times when a lack of expansion ability can contribute to those problems.

If you're going to spray foam up there, make sure you don't put more than you need in... it can expand A LOT.

Originally posted by @Loren Thomas :

If you're going to spray foam up there, make sure you don't put more than you need in... it can expand A LOT.

 I'm now pretty cautious with the foam.  There was the incident where I was filling a termite damaged window frame and bulged out the exterior stucco wall.  Thanks for the reminder though!

Trace the lines by sight. The one that comes in the house is cold...needless to say. Knowing is the only way to know. Process of elimination

Definitely need to ID if the supply to toilet is hot.  If you don't want to flush 32 times, disconnect the supply hose from the tank and let it run into a bucket.  Stop the flow and dump into tub or sink if it takes a little more than 5 gallons.  Run the hot in the bath sink & tub next to the toilet to get the warming started maybe.  5 gals should tell you if it's a hot line or not after pre-warming in sink and tub/shower.  

Kristine Marie Poe I will take a bit different track here from the others. Are you familiar with water hammer. If the cold water flows fast or starts flowing fast it can create a pressure wave through the piping system which can make the noise you speak of. Does the water heater have an expansion tank on it? If it's water hammer then adding an expansion tank will help. Having air trapped in the pipe might also cause the noise but that usually includes frothy water as well.

I have not heard of the copper pipe making noise just because it's not properly connected but it's possible. 

@K. Marie Poe What everyone is saying is correct to some point. All I will tell you from being an experienced licensed plumbing contractor is process of elimination. 1st turn off the angle stop (valve to the toilet). 2nd disconnect the supply line from the toilet tank only leaving the connection on the valve. 3rd go get a pot (deep) and position the end of the supply line that you disconnected from the toilet tank and put the end into the pot (your going to have to hold it there by hand). Last turn on the toilet angle stop while supply line is pointed into the pot and let it fill, if you get hot water then you have a crossed line and you will have to remedy the problem. 

     It works much better than flushing the toilet over and over again until you get hot water in the tank. Also make sure your cold water on your Lav (sink in the bathroom) is cold and not hot ( hot is on the left and cold on the right). 

     If the water is coming into the toilet tank is cold and the water heater is still doing the same crackling noise, you should check the water heater, people don't know but you as a homeowner are suppose to drain and flush your tanked (not tankless) water heater every 6 months.

    Hope this helps!

Free eBook from BiggerPockets!

Ultimate Beginner's Guide Book Cover

Join BiggerPockets and get The Ultimate Beginner's Guide to Real Estate Investing for FREE - read by more than 100,000 people - AND get exclusive real estate investing tips, tricks and techniques delivered straight to your inbox twice weekly!

  • Actionable advice for getting started,
  • Discover the 10 Most Lucrative Real Estate Niches,
  • Learn how to get started with or without money,
  • Explore Real-Life Strategies for Building Wealth,
  • And a LOT more.

Lock We hate spam just as much as you

Join the Largest Real Estate Investing Community

Basic membership is free, forever.