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    SRQMOVE's Avatar
    SRQMOVE Posts: 10, Reputation: 1
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    #1

    Apr 29, 2018, 02:16 PM
    Tankless hot water heater not delivering water for more than a couple minutes
    We just moved into a newly built house, and the plumbing issues are unbelieveable!


    We have an AO Smith 510 Tankless water heater. It took 15 minutes to get hot water to the master bath sink our first morning here. The Master bath is the room closest to the tank. We placed the heater purposely so we’d get water there the most quick. But not only did it take 15 minutes, but the hot water only lasted a couple of minutes, then went ice cold for 2 minutes, then hot again, and again only stayed hot a few minutes.


    And the shower – well, that sure was fun. Took about 2 minutes later in the afternoon to get hot water, so I got into shower, but then about 5 minutes later, lost the hot water completely. When my wife showered several minutes later, she managed to have hot water for the entire shower. But we could not adjust the water temp of the shower – the knob from the fixture that adjusts temp came off in my hand.


    Then today it was even worse. I turned on the hot water in the master bath, but after 40 minutes gave up trying to get hot water. Went upstairs and ran the hot water, and a few minutes later, we had hot water up there. After about an hour of hot water running elsewhere in the house, we finally had hot water in the master bathroom. And the “hot” water in the kitchen never got beyond lukewarm, except for about a minute of hot water.


    This is absolutely ridiculous. This is an expensive, new, custom designed house. Our neighbor next door, hearing of our issues, timed his hot water – the FURTHEST point in his house had water in 35 seconds first thing in the morning. Same hot water heater. I cannot conceive of having to replumb the house, but I am afraid that may be necessary. The house was already double the estimated build time, and I’d hate to move out after just moving in. But I want hot water!


    Oh – and a brief By The Way – one of our NEW toilets run. And the A/C is messed up too. 10 degree difference from one room to another. This is a really “great” builder. BUT I DO NOT KNOW WHAT I CAN DO AT THIS POINT! ☹
    talaniman's Avatar
    talaniman Posts: 54,327, Reputation: 10855
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    #2

    Apr 29, 2018, 03:10 PM
    https://www.hotwater.com/lit/catalogs/aosbg80000.pdf

    From everything I have read this isn't a job for most experienced handymen and requires a qualified tech to go through and check the system settings. You make no mention of a led error code readout, and all the 510 tankless series should have on. The included pdf has the proper settings to be checked, and a manual look up got this...

    https://www.manualslib.com/manual/81...Smith-110.html

    ...Start at page 7

    Applies to 110 series to 510 series
    massplumber2008's Avatar
    massplumber2008 Posts: 12,832, Reputation: 1212
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    #3

    Apr 29, 2018, 03:36 PM
    All work is under warranty... call the builder back and have him send the plumber out to fix the problem. Most likely, from what I read, you have a CHECK VALVE missing in the system and are getting a cross over of cold into hot.

    If you have any problems call the local plumbing inspector and have him pop over. He signed off on the work, so he shares some responsibility here as well and I'm sure he will set up a meeting between you, the plumber that did the work and himself, if nothing else, to stop you from calling him ​again! LOL!

    Mark
    SRQMOVE's Avatar
    SRQMOVE Posts: 10, Reputation: 1
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    #4

    Apr 29, 2018, 07:18 PM
    Would this valve be something that is right at the heater, or is it something in the walls, requiring the plumber to take down drywall to get to the piping? We've only been in this house 2 days! The builder claims the plumbing is "complete" and seeking full payment. :-(

    THANK YOU
    massplumber2008's Avatar
    massplumber2008 Posts: 12,832, Reputation: 1212
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    #5

    Apr 30, 2018, 02:04 PM
    Valve would be accessible and near the water heater.

    1) Do NOT pay this person until this is resolved 100% to your satisfaction.

    2) Again, you have full warranty... easily enforced especially if you don't make full payment

    3) Get a thermometer from home depot for measuring water temperature (about $10.00 in plumbing section) and use your camera phone to record the time from low temperature to high temperature. Send this video to the builder, the plumber and the real estate agent, if one was involved, and tell them you will not pay in full until the problem is resolved at NO COST to you.

    4) Contact your lawyer if they get nasty or act unprofessionally. In fact, if they are acting lousy about this I would threaten to hold back a significant portion of the final payment because you are worried they will act as unprofessionally as they are if anything else pops up!

    Remember, you have rights here. At a minimum, all contractors on the job are required by law to warranty all work and materials to be free of defects, or they fix at no cost to you for the first year!

    Mark
    SRQMOVE's Avatar
    SRQMOVE Posts: 10, Reputation: 1
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    #6

    Apr 30, 2018, 03:10 PM
    I plan to withhold final payment from the builder until this (and the inadequate A/C, and wobbly floors) are fixed.TOday the plumber actually showed up. He opened a valve right by the heater and let the water run out there. Then he noted that the filter was clogged. He cleaned that. Then he tried running the hot water in the master bath.It got hot within a minute - VERY HOT. But 2 minutes later, it was cold again, and stayed cold for several minutes until it became hot again.Then tried the kitchen. GAve up waiting after 20 minutes of not having hot water.This afternoon though I was able to take a shower in the master bath, and the water stayed hot the entire shower. Two quotes from the plumber: You need a recirculation pump for this house," and "This is very weird."Our house is not all that big - it is only 2800 sq ft in 2 storiesTOmorrow a representative from the builder is going to be here, along with an inspector hired by our bank, who has to determine how much is "complete" for the builder to get another draw from our mortgage, and a construction litigation consultant we hired.
    massplumber2008's Avatar
    massplumber2008 Posts: 12,832, Reputation: 1212
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    #7

    Apr 30, 2018, 03:47 PM
    All sounds good so far!

    You said, "Gave up waiting after 20 minutes of not having hot water"...who gave up, you or the plumber?

    You said, "VERY HOT". Hot water to shower is not allowed to exceed 115F in most states. Call your local plumbing inspector and ask him maximum temperature allowed in your state. Then get that cheap thermometer at home depot and measure the temp. coming out of that shower. If the temperature exceeds 115F make sure the plumber adjusts the temperature limiting device on his next visit (easily adjusted at the shower valve under the handle or trim) to all shower valves. FYI, besides showers and tub and shower valves, maximum temperature that can be delivered to any fixture in the home is 120F, so check the sinks in the home at maximum hot and see what they are reading at...if exceed 120F again, have plumber adjust the hot water output from tank. NOTE: There are a few states that allow 140F water to a dishwasher, but even in those states, water going out to the rest of the house must be "mixed" down to 120F to sinks and shower valves and tub and shower valves must be adjusted to 115F. I give you this information just as a little leveraging power if/when needed AND because you might have children now or in the future and this information could prevent any scalding or burns to family members!

    A recirculating hot water line should not be needed in most homes your size (as you described) so be careful here. If needed, again, consult the local plumbing inspector. He will know the homes in your area and should be glad to consult if you genuine and don't get pissy about the plumber that worked on the house. Lots of SUGAR goes a long way here!!

    Keep us posted.
    SRQMOVE's Avatar
    SRQMOVE Posts: 10, Reputation: 1
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    #8

    Apr 30, 2018, 05:58 PM
    Lots of sugar! :-) Have been trying that, and recently my lawyer said to me "Why the heck are you being nice to him?" referring to my builder.

    It was both the plumber & I that gave up - he sort of shrugged his shoulders and just said things weren't right. As I quoted him earlier - "this is weird"

    THe temp is not so much of an issue as the lack of long time needed to get hot water, and it then turning cold.

    So what happened tonight - I turned on the kitchen faucet after dinner, the one where after 20 minutes there was no hot water 6 hours earlier. Water was hot in less than a minute! THat's IS weird - the inconsistency is mind boggling.

    I am betting that there is something wrong with the way the plumbing was done at rough in. I looked in the docs the builder submitted to the city, and there is NO plumbing document. So I am wondering how they passed the rough in.
    massplumber2008's Avatar
    massplumber2008 Posts: 12,832, Reputation: 1212
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    #9

    May 1, 2018, 01:35 PM
    Rough inspections are done on site after the rough plumbing phase of the job is finished... just prior to closing the walls in. Finish plumbing inspection is done when everything is complete and the plumbing inspector walks through the job making sure that proper temperatures are set at each fixture amongst other things, so there is not usually a "plumbing document" in most cases.

    Keep us posted...

    Mark
    SRQMOVE's Avatar
    SRQMOVE Posts: 10, Reputation: 1
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    #10

    May 1, 2018, 01:47 PM
    The City inspector here (FL) does not check for temps.
    THat is something the owner has to do in the walkthrough.
    And the temps are wrong in too darn many places.
    Stratmando's Avatar
    Stratmando Posts: 11,188, Reputation: 508
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    #11

    May 3, 2018, 06:22 AM
    You could put an Amprobe on the wires at the Water Heater. You will see if it is even Heating, and when it is not, Some of those use Thermals you can buy at an Auto part store that sometimes fail, when they open, they don't Heat. Good Luck Not your job to fix.
    Milo Dolezal's Avatar
    Milo Dolezal Posts: 7,192, Reputation: 523
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    #12

    May 4, 2018, 07:06 AM
    Hello, is there hot water circulation pump installed on the system ?

    Milo
    SRQMOVE's Avatar
    SRQMOVE Posts: 10, Reputation: 1
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    #13

    May 4, 2018, 07:16 AM
    NO - there is no recorc pump. As mentioned, the plumber who installed it said (after the fact) that we needed one. BUT I believe that a recirc pump defeats the purpose of a tankless heater, at least with regards to energy efficiency. And it adds more complexity to using the household utilities (We're Old people!).

    How water is pretty good in master bath (right next to heater), after about 2 minutes it is hot & stays hot. But the best we get everywhere else is lukewarm water.
    Milo Dolezal's Avatar
    Milo Dolezal Posts: 7,192, Reputation: 523
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    #14

    May 4, 2018, 08:33 AM
    Is your house on concrete slab ? If so, are your pipes ran bellow the slab ? Just curious...

    Milo
    SRQMOVE's Avatar
    SRQMOVE Posts: 10, Reputation: 1
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    #15

    May 4, 2018, 07:25 PM
    Yes - house IS on a concrete slab.

    We found the remote today - it is a hard wired remote and was inside the heater housing. THe water temp was set at 120, the default temp, but the output was 115. Not sure if that is an issue. But cranked the temp setting up to 131, and now things are much better. We finally get HOT water in the furthest areas, but it still takes a couple of minutes to get there.
    Milo Dolezal's Avatar
    Milo Dolezal Posts: 7,192, Reputation: 523
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    #16

    May 4, 2018, 10:08 PM
    Glad to know you are getting hot water now. Unfortunately, without hot water circulating pump, you will have to wait for hot water. As you mentioned above, circulation pump defeats the purpose of tankless water heater - and I echo your comment. You could possibly install retrofit pump with timer, and set timer for time when you are expected to use shower. Other time of the day the pump will be off. You could also remove flow restrictor from shower head to get better flow, and faster hot water delivery.

    Milo
    SRQMOVE's Avatar
    SRQMOVE Posts: 10, Reputation: 1
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    #17

    May 20, 2018, 05:45 AM
    Hello - it is ME again.
    Plumber still trying to figure out what is wrong with our system, and still suggesting a Recirc pump as the "only" solution. As above, this defeats the purpose of the tankless. Another issue that I just realized - we have a HE washing machine. When it washes, it does so with small bursts of water. So how the heck can it get hot water, since it takes several minutes for hot water to get from the heater to the machine? Would a Recirc pump even help that? There is no sink/faucet anywhere near the washing machine, so I can't do what I did in a prior house that I had rented that had poor plumbing - run the water in the sink for a couple of minutes to get hot water to that area.

    ANother issue with a Recirc Pump - aren't you pretty much heating the entire house as you now have constant hot water running in the walls. No need for extra heat in Florida. I do not trust the plumber my builder used to make sure the plumbing is insulated perfectly.

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