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Thread: Shower is sometimes hot and sometimes just warm?

  1. #1
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    Shower is sometimes hot and sometimes just warm?

    We recently moved into a new house, went from owning to renting for a year. Anyway sometimes the master bathroom shower is very hot, sometimes it's just warm or barely warm. We had a plumber in to fix or adjust the "scald valve" I think it's called. Before that or was always just warm, now it's like I said sometimes hot to really hot but more times than not it's warm to borderline cool. Not refreshing at that temp. What could cause that as all the other faucets and the other shower is as hot as can be? Not the water heater right? Thanks for any help.

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  2. #2
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    I used to be a plumber and most of the time this problem was caused by single handle faucets. With a single handle faucet the hot a cold lines come together near the cartridge. This can cause the cold to cross over to the hot side. Try closing the angle stops for your lav sinks and test this for a couple days

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  4. #3
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    i have a feeling you have a tankless hot water system that the flow was not dialed in/adjusted correctly..or there is a problem with the sensor in the unit...that needs to be looked at...i have an electric tankless in my home where i can select the heat temp output to not scald and it is fully modulating to adjust to incoming water temps..

  5. #4
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    Quote Originally Posted by James Colver View Post
    I used to be a plumber and most of the time this problem was caused by single handle faucets. With a single handle faucet the hot a cold lines come together near the cartridge. This can cause the cold to cross over to the hot side. Try closing the angle stops for your lav sinks and test this for a couple days
    A little over my head but I understand some of that. It is a single handle faucet. The lines are getting crossed? Is that basically what you are saying? How would I go about fixing this? Take the handle apart?

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  6. #5
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    Call the plumber back.

    Sounds like an issue with either the shower valve, or a valve near by, like the sink.


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  8. #6
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    Quote Originally Posted by heatingman View Post
    Call the plumber back.

    Sounds like an issue with either the shower valve, or a valve near by, like the sink.


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    Yes, since we are renting we will get a plumber from the other of the house. Thanks for the help.

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  9. #7
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    How do you find the cost to operate?

    How much amperage does your unit require?

    PHM
    --------



    Quote Originally Posted by Unlimited1 View Post
    . . . . an electric tankless (water heater) in my home where i can select the heat temp output to not scald and it is fully modulating to adjust to incoming water temps..
    PHM
    --------
    The conventional view serves to protect us from the painful job of Thinking

  10. #8
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    Quote Originally Posted by HVACannoyed View Post
    A little over my head but I understand some of that. It is a single handle faucet. The lines are getting crossed? Is that basically what you are saying? How would I go about fixing this? Take the handle apart?
    Some faucets have Anti-Backflow device built into them , and it goes bad

    I once found a Jet Tub doing this

    I turned off the water valves going to the Jet Tub and suddenly all the other faucets around the house began working fine again

    So .... what you can do is ... reach under a sink and turn off both valves on a sink , then see of the other sinks work better

    Then turn that one back on , and turn off another sink

    The shower valves will "probly" be inside the sheetrock wall, so hopefully you have a access panel to test this one

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  12. #9
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    During off season (swing seasons)... sometimes I do some 'handy' work...

    About a month ago... had a rental owner call me... similar issue...
    Shower was running warm, would not heat up...
    Went out and looked at it...
    Ended up at HD, getting a new cartridge for the valve (you have to leave the water off while you take the old cartridge to HD to match it up)...
    Be careful of the washers and springs when you pull the old valve... sometimes parts fall out...
    After the new valve cartridge was installed... all is good.

    Note: if you have a tankless... and you have a low flow shower head...
    You may be getting 'sandwiching'... when the tankless cycles on and off...
    Thus a hot/cold stream from the hot line.

    The way to determine if this is happening...
    Is to open only the hot water at a 2 valve sink faucet...
    Open it just a little... let it run until it is hot... then see if it STAYS hot, or goes hot/warm/hot...
    GA-HVAC-Tech

    Your comfort, Your way, Everyday!

    GA's basic rules of home heating and AC upgrades:
    *Installation is more important than the brand of equipment
    *The duct system keeps the house comfortable; the equipment only heats and cools (and dehumidifies)
    *The value of comfort, over the long term; leave economic choices behind!
    Choose your contractor wisely!

  13. #10
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    Quote Originally Posted by Poodle Head Mikey View Post
    How do you find the cost to operate?

    How much amperage does your unit require?

    PHM
    --------
    you only use electric when you are using/needing hot water. i have the low flow shower heads/faucets as well for a lower water usage and all bathrooms/ faucets can be used..

    i chose this brand many years ago due to reliability and very high customer satisfaction ratings...other brands copied their design..

    it is fully modulating, and adjusts to incoming water temps..so output temps stay consistent the at your setpoint. hangs on the wall and i have a much lower electric bill..i also relocated the plumbing from the old 50 gallon tank and installed mine in the washroom as it was much closer to the electrical panel and do the wiring..it took me a day to do everything for a very clean look..

    you can always prewire and preplumb everything first if you are short on time

    https://www.ecosmartus.com/product/e...s-Water-Heater

    i installed a sediment filter after the incoming water supply to my home as its in a well

    i also have the service isolation valves on it as i clean mine once a year with white vinegar...
    this is a generic online pic of one with the service/isolation valves installed on it, that some home owner installed on their own..
    https://i.pinimg.com/originals/51/49...84abc4a1cf.jpg


    ecosmart brochure https://s3.amazonaws.com/WebPartners...6549D159B4.pdf
    the 18 is 2x 40 amp breakers with 8 awg
    the 24 and 27 is 3x 40 amp breakers with 8 awg..

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  15. #11
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    I have a pair of ShureComfort (Rheem clone) 160K condensing tankless (with twinning cable) feeding my bathrooms...
    And a third one feeding the kitchen/laundry/sink in the garage (sink in the garage is 2' x 3' x 18" deep restaurant SS sink).

    Got all three tankless at a supply house that went out of business.

    LOVE tankless... IMO it should be code for ALL new construction!
    GA-HVAC-Tech

    Your comfort, Your way, Everyday!

    GA's basic rules of home heating and AC upgrades:
    *Installation is more important than the brand of equipment
    *The duct system keeps the house comfortable; the equipment only heats and cools (and dehumidifies)
    *The value of comfort, over the long term; leave economic choices behind!
    Choose your contractor wisely!

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  17. #12
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    Quote Originally Posted by ga-hvac-tech View Post
    I have a pair of ShureComfort (Rheem clone) 160K condensing tankless (with twinning cable) feeding my bathrooms...
    And a third one feeding the kitchen/laundry/sink in the garage (sink in the garage is 2' x 3' x 18" deep restaurant SS sink).

    Got all three tankless at a supply house that went out of business.

    LOVE tankless... IMO it should be code for ALL new construction!
    when i did new home large home construction, they all had bosch gas tankless units in the outside and it was always at the outside master bedroom area, no exceptions...i ran all the gas piping to the AH/gas stoves/fireplaces and water heaters as they used CSST and black piping per code..i was 1 of 2 techs (out of 14) that never had leaks, or failed inspection lol..

    the biggest problem i ever had was the hardiplank siding guys used too long of a nail piercing the csst, (they also did it to the copper linesets also) second to the sheetrock guys putting a random blind screw where it did not belong( the plumbers hated them also, lol...the siding guys tried to say the install was the problem of the gas pipe too close to the exterior wall but i used the webbing strap 3x with roofing nails to hold it dead center and all my work was fully inspected..Pictures dont lie when you open up the interior wall and there is a 3.5" nail in it..they was not supposed to use more than a 2" nail...as per hardiplank instructions..
    Step 1

    Go to the nail section in any hardware store. It can be a local hardware store, or one of the larger chain stores.
    Step 2

    Pick out stainless steel or hot-dipped galvanized nails size 6d, 1 1/2-inch-long siding nails and 2-inch long siding nails in the quantity you need for your project. If the Hardiplank is being installed on a building in a humid climate or near the ocean or any large body of water, the stainless steel nails are the first choice.

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  19. #13
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    Quote Originally Posted by Unlimited1 View Post
    when i did new home large home construction, they all had bosch gas tankless units in the outside and it was always at the outside master bedroom area, no exceptions...i ran all the gas piping to the AH/gas stoves/fireplaces and water heaters as they used CSST and black piping per code..i was 1 of 2 techs (out of 14) that never had leaks, or failed inspection lol..

    the biggest problem i ever had was the hardiplank siding guys used too long of a nail piercing the csst, (they also did it to the copper linesets also) second to the sheetrock guys putting a random blind screw where it did not belong( the plumbers hated them also, lol...the siding guys tried to say the install was the problem of the gas pipe too close to the exterior wall but i used the webbing strap 3x with roofing nails to hold it dead center and all my work was fully inspected..Pictures dont lie when you open up the interior wall and there is a 3.5" nail in it..they was not supposed to use more than a 2" nail...as per hardiplank instructions..
    Step 1

    Go to the nail section in any hardware store. It can be a local hardware store, or one of the larger chain stores.
    Step 2

    Pick out stainless steel or hot-dipped galvanized nails size 6d, 1 1/2-inch-long siding nails and 2-inch long siding nails in the quantity you need for your project. If the Hardiplank is being installed on a building in a humid climate or near the ocean or any large body of water, the stainless steel nails are the first choice.
    The siding guys probably found a 'deal' on some off brand nails that fit their gun...
    Who cares about proper size and type...

    Down here... when HardiBoard siding was getting popular in new construction...
    Folks would put it up with a roofing nail gun...
    Nails only at the top (under the next lap)...
    Turned out to not be very resistant to wind...

    At that supply house that went belly up...
    I ended up with boxes and boxes and boxes of TracPipe fittings...
    And something like a couple thousand feet of pipe (mostly 1/2 and 3/4)...
    Most of it has been used since...
    GA-HVAC-Tech

    Your comfort, Your way, Everyday!

    GA's basic rules of home heating and AC upgrades:
    *Installation is more important than the brand of equipment
    *The duct system keeps the house comfortable; the equipment only heats and cools (and dehumidifies)
    *The value of comfort, over the long term; leave economic choices behind!
    Choose your contractor wisely!

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