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Sediment in Hot Water - Smart Phase III 30 Gal.

I have very low flow rate for hot water into the bathtub/shower. Hot water flow is adequate in bathroom sink and kitchen sink. I've replaced the balance spool assembly in the shower line twice in the last year, the shower head twice and the stem unit assembly. Hot water flow improves for a couple of weeks, then reverts to low flow, both from the bathtub spigot and the pipe leading to the shower head.
Recently, the hot water flow to the kitchen sink dropped way off. I cleaned the aerator - no change. Took apart the hot water line running up to the sink. At the "T" junction for hot water going to the dishwasher, the line was plugged with layers of a thin, white substance (dried, it looks like paper, but isn't). Cleared that out and flow was fine.
I only have a problem with the hot water line.
The Smart Phase III indirect boiler has no drain valve at the bottom, so I can't flush the tank (tanks, I guess, since there is an inner and an outer). Can there be sediment - like this white, papery stuff - in the hot water tank that is getting into the pipes and plugging the lines?
If there is sediment, how do I deal with it/eliminate it?
Or, do I have a different problem?

Comments

  • Jamie Hall
    Jamie Hall Member Posts: 15,724
    Sediment wouldn't look like what you are describing, so... are you on city water or well water? Are there filters or softeners of any kind on your water supply? Have you had the water quality tested? if so, what were the results?
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • RetiredinCT
    RetiredinCT Member Posts: 4
    City water. There are no filters or softeners. I have not had the water tested.
  • hot_rod
    hot_rod Member Posts: 14,748
    Blockage is some times at the connections to the tank

    Is the tank connected with dielectric type unions? A silver and brass looking nut connection?
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • HVACNUT
    HVACNUT Member Posts: 3,906
    Tephlon tape?
    I've condemned quite a few TT tanks but never saw or heard of that.
  • Jamie Hall
    Jamie Hall Member Posts: 15,724
    OK, next question. What temperature are you holding the tank at?
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Jamie Hall
    Jamie Hall Member Posts: 15,724
    In case you're wondering, I'm thinking a biofilm... is there adequate chlorine residual in the water?
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • RetiredinCT
    RetiredinCT Member Posts: 4
    Hot Rod … I don't see any "silver and brass looking nut connections" at the tank. The connections all appear to be copper tubing connected to the input/output. The connections are threaded and there is Teflon tape on the threads.

    Temperature … ah, there's the rub. We've been in this home about two-and-a-half years. At house inspection, the inspector said the hot water temperature was set "excessively high". On the hot water heater, the temperature dial was up into the orange. We turned the thermostat on the HWH down to normal. Over time it became clear that the previous owner increased the water temperature in order to get an adequate amount of hot water to the shower area.

    After replacing the balance spool assembly and the stem assembly the first time, the amount of hot water flow from the shower head and the tub spigot improved. Over several months, the flow consistently degraded. We turned the temperature up on the HWH to get more hot water to the shower. Eventually, I replaced the balance spool assembly a second time and tried to back-flush the system (opening the spigot in the basement powder room and blocking any water flow from the tub spigot and shower head). Again, it worked for awhile. We turned down the HWH temperature. But in weeks, not months, the flow degraded again - which is when I found the blockage to the hot water line in the kitchen sink.

    Could the deposit I found in the kitchen sink hot water line (thin sheets that look like paper) be Teflon tape degraded by too high water temperature? Could that plug the hot water line from the bathroom sink to the shower/tub? How do I clear it?

    And I don't know anything about chlorine residual.
  • hot_rod
    hot_rod Member Posts: 14,748
    If you run high temperature, over 120F you should install a top brand thermostatic mix valve. Run the tank 140- 150F with a mixer.

    Is the flow reduced or the amount of useable hot water?

    A 5 gallon bucket under a faucet or shower head will show you actual gpm flow rate. A thermometer shows available temperature across that drawdown

    Be sure the tank is up to temperature when you start
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Jamie Hall
    Jamie Hall Member Posts: 15,724
    In my humble opinion... to eliminate the possibility of bacterial growth in the hot water and to eliminate the possibility of biofilms, the hot water heater should never run cooler than 140 F. It should be followed by a thermostatic mixing valve to bring it down to 110 F, but if possible allowing full temperature water to the dishwasher and to the laundry machines. Thermostatic mixing valves (not the balance spool pressure balance type, which do not actually react to temperature -- true thermostatic mixers) can be used for each bathroom group and for the kitchen sink and any hand wash or utility sinks.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • RetiredinCT
    RetiredinCT Member Posts: 4
    OK, thanks, Hot Rod. I can try that.
    The flow of hot water is the issue, but only in the tub/shower. The flow of hot water appears adequate at each other location - bathroom sink, kitchen sink, powder room sink.
    The amount of useable hot water has not been a problem.
    Should I do the GPM flow test from the kitchen sink, also … just in case? But I don't see how the GPM flow test will help me figure out why/how the line to the shower is blocked.
  • hot_rod
    hot_rod Member Posts: 14,748
    Sink faucets typically have flow restrictions in the aerator, easy to remove and clean. Showers are sometimes in the head, remove and Check flow right from the shower arm. That would eliminate a clogged head.

    Sometimes you can delime heads, or replace with newer design. Delta has some nice low flow models that you can get wet under.

    Or it could be crud in the cartridge.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Larry Weingarten
    Larry Weingarten Member Posts: 2,127
    edited February 2020
    Hi, I've found this sort of stuff plugging up lines. It comes from the plastic coating on gas fired heater thermostat probes. I'm wondering if your indirect has any plastic coated parts inside. :o Is your sediment looking something like this?

    Also, Is there a hot water recirc line? If so, is there a working check valve in it? If not, sediment could flow backwards through that line.

    Yours, Larry
  • mattmia2
    mattmia2 Member Posts: 2,855
    @Larry Weingarten that looks like some sort of a calcium salt. The steel wire in the anode of my old water heater had a similar coating that had replaced the magnesium after it had dissolved.
  • hot_rod
    hot_rod Member Posts: 14,748
    also similar to the bad dip tubes breaking down, I don't think that tank has a dip tube/ bottom feed.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 8,823
    @RetiredinCT

    If you get it working I would install some type of filter or strainer in the hot water line as soon as it leaves the water heater. Install unions and or valve to make the strainer/filter easy to service
  • Larry Weingarten
    Larry Weingarten Member Posts: 2,127
    Hi and yes, this is similar to dip tube bits, but thinner. It clearly is plastic, so not coming from the anode. Also it’s about the same weight as water, so is a pain to completely get rid of. Might be nice to see a photo of the stuff that @retiredguy is seeing. I might take a flame to it and see if it melts like plastic or just sits there like some mineral salt. :p
    Yours, Larry
  • mattmia2
    mattmia2 Member Posts: 2,855
    oh, that is some sort of fiber filled plastic and that is the fiber base with some resin holding it together?
    BillyO
  • Larry Weingarten
    Larry Weingarten Member Posts: 2,127
    Hi @mattmia2 , It's likely some heat shrink tube they use to prevent galvanic corrosion. I'm guessing hot water degrades it over time, though this breakdown is rare in my experience. :o

    Yours, Larry
  • clammy
    clammy Member Posts: 2,647
    Check the dip tube on the cold water inlet I have seen them disintegrate and effect output , by only having a very limited hot water supply as then quickly back to cold . Remove the cold water inlet and check it out . I ve had a few which this was the issue and the tank did not need to be replaced . There not my favorite tank to remove and I’ll leave it at that . Peace and good luck clammy
    R.A. Calmbacher L.L.C. HVAC
    NJ Master HVAC Lic.
    Mahwah, NJ
    Specializing in steam and hydronic heating
  • JUGHNE
    JUGHNE Member Posts: 8,261
    The dip tube on my 1995 storage tank broke.
    I replaced it with 3/4" OD ACR copper tubing, a flare on the top end to match the original holds it in place.
  • Larry Weingarten
    Larry Weingarten Member Posts: 2,127
    Hi @JUGHNE , That works, but be sure to check the anode! If it’s a glass-lined tank, the copper could cause damage >:)
    Yours, Larry
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