Distance to Water Tank Question

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by statjunk, Jul 6, 2007.

  1. statjunk

    statjunk DIY Senior Member

    Hello All,

    I would like to make a thorough description of the situation to see if you guys have any theories as to what may be the problem.

    Here goes: The house is a slab home built in 1954. It is a large 2800+ sq ft ranch that has in ground heating via a boiler. The boiler is original to the house and is a total hog. (this is only part of the problem). My February heating bill was $879. Yes you read that correctly! So enter the recent future. I no longer run the boiler and the only appliances that I've been running are the hot water tank and the washer and dryer. My June gas bill was $180. I'm the only person living in the house. I take one shower per day and do one load of laundry per week and maybe one extra per month, linens and other stuff. There is no dishwasher. The master bathroom resides about 65' from the hot water tank and the hallway bathroom is about 45' from the tank. The water lines are copper and all run under the slab. When taking a shower in the master it can take up to about 7-8 minutes before hot water reaches that shower. The hallway takes maybe a minute. One of the enigmas is that hot water reaches the master bath sink much quicker than it does the shower. Just under 3-4 minutes. I recently installed a new Whirlpool hot water tank so the efficienty issue may have been resolved but I don't think there was anything wrong with the original tank. It still takes a long time for the hot water to reach the master bath.

    I recently demolitioned the master bath and the valves under the sink leaked so I went ahead and replaced the values. Worth noting, it took me over a half hour to get the water to stop coming out of the pipe. I was sucking it out with the shop vac. It kept coming in waves. (it would stop for a bit and then water would come out) The entire house is one big remodel so I'm unable to drain much of the water from the lines when I cut the water at the meter.

    I've got two questions

    1) What might be going on? Why does it take so long for hot water to arrive at the master but not as long to get to the hallway bath?


    2) How might I resolve this? I'm installing a 75 gallon jacuzzi jet tub in the bathroom so I will need lots of hot water in this room.


  2. Rancher

    Rancher Guest

    One possibility is that the Master bath water goes first to the kitchen and then on to the MB. And the Hall bath was a separate straight run. Since this is a re-model you might think about replumbing with PEX thru the overhead, and use direct runs with a manifold system at the heater. AND plumb in a hot water recirculation system.

  3. markts30

    markts30 Commercial Plumber

    Phoenix, AZ
    A second possibility is to place on of the re-circulation systems under your lavs in the bathrooms...
    They work by pumping the cold water in the hot water line into the cold line until hot water is sensed at the valves...
    They might not speed up the arrival time of hot water but at least you will not be wasting water.
    As well, when getting ready for a shower, switch it on and there will be hot water ready for you by the time you are ready to get in...
  4. statjunk

    statjunk DIY Senior Member

    Is there some way for me to put a small electric water heater for just that room. Similar to a tankless system but a smaller cheaper unit for just that bathroom?

  5. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    New England
    There are small WH designed for a sink, but you could feed them from the hot water line, and thus have its capacity to give you instant hot water until the hot gets to the tank. These can be plugged into a 120vac outlet.
  6. a 1954 slab is likely to be uninsulated underneath, so you lose to the ground underneath far more heat than you gain in the house above the slab. A bad deal. If this is a total redo, add a padding membrane like 6mm cork, then put down electric heat cables on top, then tile that. Warm floor, low cost.

    How big is the new HW heater? What size diameter pipe is its outlet? Are all your pipes 1/2" in diameter? Is one of them 3/4" in diameter?

    For your new tub, you may want the filler spout to produce a lot of water flow (otherwise you might wait ten minutes to fill it, after you get hot water to it). So you have every reason to put large diameter Pex pipes as already suggested. Insulate them.

    When I see the floor layout plan, I might feel comfortable commenting on the time it takes now, for HW to reach the tap, spout or nozzle. It is only because of the length of the pipe (total distance) and the pipe diameter.

  7. Terry

    Terry Administrator Staff Member

    Bothell, Washington
    I would think a dishwasher would be the cheapest way to wash dishes. They use less water.

    As far as filling a 75 gallon tub, you better have enough size in your water heater to fill it.
    A circ pump helps with that, you have more volumn of heated water, and none of it going down the drain.
    There is some heat loss if you don't have the pipes insulated. You could always run a insulated pex line back for your recirc.
    Or the recirc pump that pumps your hot into the cold unitl it reaches temperature.

    A small heater in the bathroom won't help much, the tankless, if you go electric needs lots of power, so that would need to be run from the box.
  8. Heat Loss In Slab

    I had a customer a while back that could not
    get anything but luke warm water to the kitchen

    one end of the house was hot but the other end could not
    get warm at all....

    the only thing I could figure out is the hot pipes must
    be going through a pool of water under the slab and
    was getting chilled off before it could reach the faucet....

    I could not do much for them but suggested either to
    get the ines out of the concrete and run them insualted overhead
    or simply learn to live with it....

    $180 permonth to heat the water seems a little stiff...
  9. molo

    molo Member

    cold new york
    Do you do alot of cooking on a gas stove/oven? That is a high june bill if you're in the lower 48.

  10. Cass

    Cass Plumber

    I want you do do this, be sure the water is on but all fixtures are off, check all toilet tanks to be sure no water is running. Go to your water meter and look at it, there should be a small triangle or arrow that will spin when water is flowing through the meter. This is a leak detector. See if it is moving. I am going to guess, at this point that you may have leak under the slab on the hot water line somewhere giving rise to your high gas bill and slow time getting hot water. This is just a guess and it will eliminate the possibility if no water is flowing.
  11. statjunk

    statjunk DIY Senior Member

    Cass and Others,

    I tested the meter like you suggested and there is no leak. At least not in the water lines that provide water to the house. However I still don't know if there are leaks in the copper lines that are part of the boiler. I would test that however I have a little bit of an issue at the moment. I unfortunely have to bust throught the concrete slab of the house and replace the drain to the shower and add a new drain for the Jacuzzi jet tub. Last night while doing this I severed one of the boiler lines and kinked the crap out of another one. The good news is that I can repair this. The bad news is that I completed about 2 lineal feet and I still have another 10ft to go. The concrete is very strong in this house. I wonder if it is because of the heat from below for so many years. Though I can say I've never worked with 4" concrete this strong before that is for sure.


    I'm curious why you said to use PEX lines. I thought the general concensus around here is that they are junk. So why did you recommend PEX? Instead of PEX could I use PVC Shed 40?

    I intend at the end of the construction project to blow in insulation. Because I will be using blown in insulation should I hang the pipes so that no one inadvertantly steps on the pipes some time in the future?

    At the very least I will be running new water lines from the 3/4" branch over the water tank to the jacuzzi jet tub. I'm considering doing the same for my shower so that I may run multiple shower heads in there.

    Thanks for the advice guys keep it coming.

    Also I will end up testing the boiler lines for leaks once I get the trench dug and all the lines fixed.


  12. statjunk

    statjunk DIY Senior Member

    Hey guys,

    I was hoping to hear back from folks.

    So is PEX a good product? Better than sched 40?

    Also how should I run the pipes in the attic in Michgan? Should I hang them from the roofing rafters because of the blown insulation?



    P.S. The cost of the crimping tool for PEX is highly restrictive! $150 for the multi-tool.
  13. GrumpyPlumber

    GrumpyPlumber Licensed Grump

    Licensed Grump
    In review..you'd checked the water meter to discern if there were any leaks.
    Scary thought in lieu of your gas bill....are you certain you have no gas leaks?
  14. Five points above. Five points covered below.

    Heat does not make concrete stronger over the years.

    " ... running new water lines from the 3/4" branch over the water tank to the jacuzzi jet tub" - i guess that means a 3/4" line. Good move.

    About the general attitude toward PEX, which you have picked up. I thought consensus around here is that pex is good. Where can you see the opposite attitude expressed? Now I am curious, Tom.

    How to run the pipes in the attic in Michigan is a good question. I think insulation around the pipes is necessary, in Michigan. I can't see your attic, so I have no idea what risk there is of anyone stepping on a pipe in your attic. Insulation is a big thing, to keep hot water hot in winter and cold water cold in summer and secondly to stop condensation on the cold water pipe in summer too. Condensation causes moisture damage and gives mold good growing conditions. I would worry about insulation a lot, and not about much about the risk of stepping on a pipe.

    The crimping tool costs $150 to buy. The tool can be rented for half a day when you have everything already strung out and in place. Other connection methods are also available; each connector then costs more but you don't need the tool. I can't say more than that on this topic.

  15. statjunk

    statjunk DIY Senior Member

    Thanks a lot for the info.

    Where I've picked up that PEX is inadequate maybe they were talking about shark bite fittings? Not sure. But I did read a post where someone was claiming that due to "this" product plumbers will have plenty of work in the future.

    Do you know what the discussion may have been about?

    Thanks again. I'm really trying to float around and give advice where I can to help others out.

  16. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    New England
    Sharkbites haven't been around that long, so with that specific brand, I don't think anyone knows about their long-term reliability - the have passed the tests to be allowed inside closed walls. Prep and proper installation is still critical with any connection, though. Where you have an o-ring, you don't want any sharp edges or burrs. The use of the deburring/champher tool is recommended before inserting the Sharkbite, or any fitting of this type onto the pipe. I like the concept of the Wirsbo (Uphonor) expansion tool, ring system. Crimps should work, but you've got a much narrower surface to create the grip you need and you should use the go/no-go tool to verify each crimp which adds a step and tool you have to carry around and calibrate.
Similar Threads: Distance Water
Forum Title Date
Plumbing Forum, Professional & DIY Advice Distance of 1/2" water pipes Mar 16, 2013
Plumbing Forum, Professional & DIY Advice how to stop hot water going cold over long distance? Mar 13, 2010
Plumbing Forum, Professional & DIY Advice PEX Manifold to Water Heater Distance Sep 15, 2009
Plumbing Forum, Professional & DIY Advice water heater distance from wall ? Jul 21, 2008
Plumbing Forum, Professional & DIY Advice Any Max and Min distance requirement between branches? Aug 29, 2014

Share This Page