Asked on Aug 16, 2012

How could tapping into hot water line to run an outdoor line affect the rest of the hot water in the house?

Delores M
by Delores M
Husband tapped in at hot water heater located in closet on back side of house, to run abt 15 yard line to new outdoor shower. Now water into house is not as hot. Checked the line and the meter for leaks, found none. Checked pilot light, on and working fine. Could it have anything to do with the distance of the new line?
  18 answers
  • Walter Reeves Walter Reeves on Aug 16, 2012 could running a branch line off a main line affect the main line? Taking a wild guess: did he somehow also work with the cold water inlet while installing the branch from the hot outlet? Maybe the cold water descender pipe inside the tank failed/dropped off and that would lead to improper mixing of hot and cold water as it exits the tank.
  • KMS Woodworks KMS Woodworks on Aug 16, 2012
    You mention a pilot I"m assuming this is a gas unit? sometimes a 'cycling" of the thermostat will clear these up...turn the knob up and down a few times then set it at its normal position. with 15 yards of run...getting hot water to this shower is going to take some may also want to insulate those long runs. did hubby put in isolation and drains for this...texas is not entirely free from winter freeze.
  • Delores M Delores M on Aug 16, 2012
    Thanks for the answers, but I'm still hoping for more ideas.
  • KMS Woodworks KMS Woodworks on Aug 17, 2012
    have you "quantified" this by taking its temp?...sometimes the finger test is a bit subjective. by comparing actual numbers you can compare the kitchen to the bath to the outdoor shower... starting with a full tank in the morning allow each location to come to equilibrium...and compare each location on a new day. report back with these numbers and we can go from there.
  • Is the hot water (new line) also connected to a faucet that provides cold water? If by chance it is, there is the possibility of a cross connection where the hot water is running through and becoming mixed with the cold lowering its temp. Run the hot water only and put a thermometer in the water to find out the temp being delivered. No more then 120 should be seen at the faucet. Are all the faucets on the hot side cooler or just one that may be on the same line as the new install.
  • Delores M Delores M on Aug 18, 2012
    The gas water heater was the first test after installation. The entire body was used as the 'check' at each shower and the forearm was used at different sinks. The new hot line is not connected to the cold until after the two new handles. In fact, the cold water line is coming in from a completely different direction - tapped into an existing line at the rabbit hut near the fence line. As there is a cut-off valve for the hot water of the new outdoor shower at the water heater from which the line comes, we will test today by shutting off the new line at the heater, waiting, and testing all indoor lines again. (it's been a busy week, couldn't get to it any sooner!) By the way, the pressure in the house has not changed. It is as if there is simply more cold water coming through the lines instead of hot. The hot is still 'hot' -- we just have to put the cold at 'barely' in order to take an indoor shower at the usual comfort level. We will keep you posted. . . .
  • KMS Woodworks KMS Woodworks on Aug 18, 2012
    considering the very long distance...the hot water will lose a lot of its heat warming the copper pipe on its way to the outdoor shower...think of it as a very long skinny radiator. given enough time...say 5 minutes of full hot it may finally come to the normal temp...I'm a short shower guy...I'm normally fully toweled off and getting dressed by the time 5 minute is up.
  • Delores M Delores M on Aug 18, 2012
    In summary, the new hot water line comes from the hot water line off of the water heater to a 'T' with a shut-off valve, all of this being copper. One side of the 'T' goes to a new outdoor hot water faucet there at the deck with the other side going to the shut-off valve and the cpvc going to the new outdoor shower which is approximately 60 feet away. The first 30 feet of this cpvc line is under the deck with the remaining footage to the shower buried. And it's not a question of the 'outdoor' shower being hot enough. It's that the 'indoor' showers are performing differently now. This morning's test of utilizing the new cut-off valve to stop any flow toward the new outdoor shower was successful. I.E., my morning shower setting was back to original. So what the heck does that mean?
  • KMS Woodworks KMS Woodworks on Aug 18, 2012
    With the long run and a buried line you might have a leak that is causing the heater to sustain a load. with the outdoor shower turned off open the shut off valve near the heater and place a screwdriver tip against the pipe and press your ear to the handle of the screw driver...this is a type of stethoscope that will let you listen to the line with out cooking your ear by the hot water line. If that line gets warm or you hear flow you have a leak.
  • Delores M Delores M on Aug 18, 2012
    Thanks, Wood, we'll give it a shot.
  • Ok, so your faucet is not a mixing type it has two individual faucet handles and the water is mixed in the spout not the valve itself. If by isolating the shower outside and the results is everything is fine, but once the outside is no longer isolated. Then the issue is with the faucets, as there is some sort of by pass going on either though the faucet itself, or the your plumbing where ever it has been connected to has caused this bypass to occur without you knowing about it. Installing any type of pipe has no bearing on the difference in temp in other areas. Only 1 cross connection or 2, faulty valve anti-scald device on the new shower in effect a cross connection is causing this issue. Leaks need to be quite large in order to effect the output temp overall on the hot water heater. So I doubt that is is. If you can isolate the hot supply side to the outside shower area at the hot water heater, can you disconnect that pipe after the valve? If so if water runs out of the pipe under pressure, then you know for sure if you have a cross connection as the cold will run back out of the disconnected pipe. Cut a Union into the pipe just past the shut off valve if you can. Open up the union once you shut off the hot water side and see if water runs out of the pipe that comes from the outside of the house.
  • Delores M Delores M on Aug 19, 2012
    So are you saying the cold water from the rabbit hut line (which is beyond the outdoor shower) could in some way come back into the outdoor showers hot water line and back 60 feet into the house and up into the hot water heater itself, therefore affecting the hot water temps inside the house?
  • KMS Woodworks KMS Woodworks on Aug 19, 2012
    Delores...would it be possible for you to pencil in a schematic of these lines valves etc. there may be something somewhere that is missing that we can not see. from your descriptions
  • Delores M Delores M on Aug 19, 2012
    Winner, chicken dinner, KMS. Just tested the theory of the cross-contamination (for lack of a better word) by using thermometer with cut-off valve opened and closed. You are correct that the cold water line coming from the opposite direction is mixing into the new hot water line and coming back into the house. While running the water with temperature gauge in place and cut-off valve closed, temp sat at 120. As soon as the cut-off was opened, we could actually SEE the temperature start to drop. Solution -- leave the cut-off valve to the new outdoor shower in the off position until someone is ready to enjoy showering in the great outdoors. Easy enough to do as we pass right by the valve on the way to the shower. Thanks for all your help!!
  • Delores M Delores M on Aug 19, 2012
    KMS, one last question: Is that some sort of one-way or directional valve that could be put in the new hot water line going to the new outdoor shower that would stop the cold water from coming back into the line?
  • Like KMS said, can you provide a schematic of the piping layout? If you have a cross connection from something else, then you piped it incorrectly. or you have some sort of faulty faucet valve. Quick question. Is the water supply (cold) that is coming from rabbit hut line a separate source or is it all from the same well, or city line? Please understand that this mix of water can be an issue of safety if the water is coming from another source or a place in which the water can become contaminated. That is why they have back flow preventive requirements on all outside garden hose bibs. If the water source is indeed coming from a line that is used for a garden, rabbit hut or any other outside use and it is making its way back into your domestic supply via a cross connection you can cause all sorts of bacteria to come back into your fresh water supply. The result is you can get quite ill. A check valve is not the answer here. Proper piping is.
  • Delores M Delores M on Aug 19, 2012
    Woodbridge, it is piped correctly. Read above. There is no backflow from said rabbit hut, it is a line that was buried across the yard to allow for easier access to water as needed at the no-longer-in-use rabbit hut. But thanks for pointing that out.
  • KMS Woodworks KMS Woodworks on Aug 20, 2012
    since you said there are no other "cross connections" is has to be a faulty shower faucet. I could see where woodbridge was going on the rabbit hut line...if your main house is at 40 psi and the rabbit line comes in at 60 psi then you would definitely has a "balance" problem. the schematic would still make us feel better