Poor hot water temperature before & after new water heater

Discussion in 'Plumbing Forum, Professional & DIY Advice, Tips & ' started by Mazcar, Jan 20, 2014.

  1. Mazcar

    Mazcar New Member

    Messages:
    13
    Location:
    TX
    Hi All,
    My condo neighbor is having hot water issues and we've thrown money at the problem at that hasn't solved the issue. I am hoping to get some guidance on this issue.

    I live in a forty year old complex. It is shaped like a rectangle with four buildings comprised of forty-eight units with half of them upstairs, and one little building inside the rectangle. The little building houses two water heaters that feed the laundry machines (also in that building) and the the four buildings. We have one water meter, so we have to shut off the water to the whole complex every time someone needs to work on something that doesn't have shut-off valves, such as a shower.

    It seems that every time we have a water shut-off, when the water gets turned back on, some of us get reduced water pressure for a while. I assume it's calcium (we live in a lime heavy area) or lime flakes that eventually get worked out.

    This past year, in one building (let's call it Building #4), the unit at the end has noted a reduced hot water temperature. A plumber came in and replaced one of the two water heaters. The guys did it during the day, when no one was home, then left. That night, we kept hearing non-stop clicking from the new water heater. I noticed a temporary blue flame with every click. Eventually, I heard a click and a swoosh and could see a nice constant flame underneath the water heater. When it was time for it to shut off and then later try to ignite again, it was clicking. I'm talking about an hour of clicking before a swoosh. I measured my temperature and it was 100 degrees. That was a significant step down from before with the old water heater. We called the plumber and he came out and adjusted a valve. Things got a whole lot better. The weird thing is that it is now, "click, click, swoosh" during the day. However, at night, it sometimes is a lot more clicking before swoosh. Day or night, it is a better than before (slightly better than with the old water heater; a whole lot better than with the new water heater before the fix). Now, the hot water temperature is either 120 or 110 degrees. There really is no in between.

    I have measured the first three condos, but not #4 and #5. The guy at the other end of the building (condo six) reports that he continues to have weak water pressure and not proper hot temperature. I don't know about these new fancy pressure regulating faucets and what is considered good vs great pressure, but his pressure seems about the same as mine. However, his temperature is terrible. I measured 103 in his vanity and under 100 in his shower and kitchen. His plumber adjusted all his temperature stops to allow for the hottest water to no avail. A lady in the middle of the building has noted her water pressure greatly reduced since the water heater replacement. I have not measured her temperature, but it is more in line with my temperature. A plumber came in and pulled off her shower-head and blasted CO2 in an attempt to remove the calcium without having to shut off water to the whole complex to clean out her shower cartridge. Her shower pressure improved, but is still not where it was before the apparent clot.

    When I have noticed a reduction in pressure, I have noticed less pressure in the second unit (compared to the first). It seems that the pressure gets reduced down the building chain. The weird thing is that I have repeatedly cleaned out the aerator in the vanity of the second unit, but not the kitchen nor shower. Why would that faucet clog more than any other?

    Well, actually, I now notice a reduction in hot water pressure in any faucet when someone else is using their hot water. Sure, it has always (for ten years) been the case, but now it's pretty noticeable.

    The water heater clicking amount seems to be an intermittent issue. Unfortunately, it seems to be okay during the day times that the plumber has come out. The water pressure seems to now be constant, except for the obvious reduction when I am competing with another unit for water.

    My theory was that the water heater has a defective component to explain the weak temperature, and that crud has clogged up units along the chain of this building to explain the water pressure.

    With my Saturday visit to condo #6 and its owner, my theory is now that there may be a catastrophic problem with the water line near that condo.

    Every unit in my complex has always had hot and cold spots in the floor. My dog can point them out as they maximize her napping locations at different times of year. The owner of the troubled condo pointed out that where he used to have a warm spot near his toilet it is now a cold spot. Again, he is at the end unit. He says that he recalls his reduced temperature problem coinciding when there was some construction hear his unit. A few months ago, we had a waste-water backup problem and the City came out and dug around. Roto-rooter came out and dug looking for a cleanout outside his bathroom-facing wall. They found an old cleanout and replaced it. I looked in that hole. I didn't see any wires nor pipes cut. The sewage pipe is around four feet down. Nonetheless, the owner reports that his hot water woes started around that time.

    The plumbers are baffled and say that the lines and water heater are fine and that we just need to decalcify the lines or replace them. That sound horribly expensive and people are afraid of having to move out.

    What questions do I need to ask and what metrics do I need to gather to present to an expert? Do you know of an expert in my area that I can call to request a visit? I can provide pictures or more detailed explanations if that might help. We're kind of at wit's end. It was a bit disheartening having our trusted plumber be out of ideas. I'm hoping you guys might have some pointers or something. As always, thanks!


    Here are a couple of bonus questions.

    When we have the water shut off, should we all open our faucets and remove the aerators to purge air and crud from the system? Should the condo furthest away from the meter turn on it's faucets? Does that not matter?

    I read on some website that the water heater should be set at 140 degrees to prevent calcium chunks from forming and then flaking off. Is that true?

    Thanks, again.
  2. cacher_chick

    cacher_chick Test, Don't Guess!

    Messages:
    3,239
    Location:
    Land of Cheese
    The first thing I would do is check the water temperature at the heater.

    If the system is leaking below the slab, the water heater will be constantly refilling with cold water, which will cause it to run way more than it should.
  3. Smooky

    Smooky Member

    Messages:
    569
    Location:
    NC
    There may be cross flows of hot and cold water where cold water is getting into the hot and vise versa. This will cause the hot not to be hot enough and may cause the cold to be warm. Cross flows of hot and cold water can sometimes happen in single handle shower valves. If you have two hose bibbs ( a hot and a cold) connected with a washing machine “Y” connect hose, can cause this problem too. Some point of use mixing valves can cause this problem if there are not proper check valves installed to prevent water from backing up. Sometimes soap dispensers are connected to mop sink faucets and the hot and cold faucets are left in the on position and this can cause a cross-flow of hot and cold water. If there is a re-circulating pump on the hot water line this will be more pronounced problem. When I find water temperatures of 100-110 this is what I suspect. That is about an average of the hot combined with the cold depending on the weather. You may have leaks and other problems as well.
  4. Mazcar

    Mazcar New Member

    Messages:
    13
    Location:
    TX
    Thanks for the tips. I had not thought about that, but 100 degrees is very suspicious. You're right. That is an average of hot and cold temperatures!

    The plumber came out (again) and said the water heater is fine. I don't know why it is so hard for them to just buy a thermometer and take an actual reading? They put their hand on input and output pipes to the water heater and are satisfied. I abolustely hate saying this, but I have to take them at their expert opinion.

    As for Smooky's suggestions, are there any tests that I can perfom myself, or is this just information to share with a plumber?

    Units #5 and #6 are the only ones with reduced water temperature. I'm not sure if #6U (upstairs unit) has a temperature problem. Of interest, though, is that all three of these units have washing machines. Units #1, #2, #3 do not have washing machines. #4 does have one, but is okay with his temperature.

    All the units have the same plumbing topology:
    * undersink kitchen h/c shut-offs that feed the faucet, dishwasher, and washing machine (if applicable)
    * undersink vanity shut-offs that feed the vanity sink
    * toilet cold shut-off
    * NO shut-off for the bath/shower

    If I shut off all the shut-off valves that I can, will that be a good test to determine cross-contamination?
    Is it possible that the problem is with #5's washing machine and bleeding over to all of #6?
    What tests would you suggest that I can do and what tests to do you suggest I mention to a plumber?

    Again, thanks!
  5. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,315
    Location:
    Cave Creek, Arizona
    The ONLY way to test for crossconnection is to shut off the inlet valve to the water heater(s) and then open hot water faucets to see if there is still flow coming out. If there is the amount of water will give an indication as the severity of it. What brand shower valves do you have? If they are Mixets, which were common in apartment/condos you may NEVER be able to cure it unless you go to a different brand of cartridge insert and replace them all.
  6. Mazcar

    Mazcar New Member

    Messages:
    13
    Location:
    TX
    Thanks so much for your suggestions. The plumbers came out today. They shut off the hot water for the entire complex at the water heaters. I tried my hot water and got nothing. Okay. No systemic cross-contamination, right?

    The issue is that unit #6 has the 100 degree hot water that Smooky suggests is the average of the 120 degrees that the water heater puts out and the 80 degrees that is normal for the cold water. Units #1, #2, and #2 all get 80 degree cold water and 120 degree hot water. Unit #6 gets 100 degree hot water (I can't recall the exact reading of his cold). If his cross-contamination is cause locally, what tests could we run? Would disconnecting the washing machine from #5, #6, and the upstairs of #6 help as a test? Note that #1, #2, #3, #2up, #3up, #5up do not have washing machines.

    I respect that you might tell me to call a plumber. We did. One said he has no idea. Another blames the hot water heater. A third is offering to sell us a fifty thousand dollar de-scaling project. While I may agree with all these guys, they are not answering the question as to why unit #6 has poor hot water temperature. That's why I am asking you guys.
  7. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,834
    Location:
    New England
    Some single handle faucet/tub valves when they wear can allow cross-over. I've not heard of a washing machine that did that internally, but some people connect the hot and cold. Some brands and models are more prone to this than others...if you provide that, some of the pros may be able to provide suggestions on where to look first.
  8. cacher_chick

    cacher_chick Test, Don't Guess!

    Messages:
    3,239
    Location:
    Land of Cheese
    You should be able to put your hand on any cold water supply pipe or washer hose and feel if it is warm or hot, which would be indication of a problem.

    Also worthy of checking is if the water heater outlet ever cools down during a time when people are not likely to be using hot water. If the pipe is hot all night several feet from the heater, it is a good indicator of a leak under the slab. Watching the meter when branches are secured can also indicate the area of a leak.
    Last edited: Feb 4, 2014
  9. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,315
    Location:
    Cave Creek, Arizona
    IF you did not get any flow out of the hot water faucet when the water heater cold water supply was turned off, then there is NO crossconnection ANYWHERE in the system. the last building would normally be where a circulation loop would be connected and also where a problem would show up when the circulation loop failed.
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