Low hot water pressure - No conventional hot water heater - Diverter valve maybe??

Discussion in 'Water Heaters and Softeners' started by Joel Carmichael, Dec 6, 2018.

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  1. Dec 6, 2018 #1

    Joel Carmichael

    Joel Carmichael

    Joel Carmichael

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    Morning All,

    So I am relatively new to the home. It has a hot water heating system I am not that familiar with. I am familiar with a typical boiler, baseboard steam heat, and hot water heater tank. I have a few pictures that show the entire system.

    My question is, where and how is the hot water heated and what would cause hot water flow to drop to the point where sinks and showers have good cold pressure but struggle to output hot water?

    I know there is the black knob shown in the attached picture which allows me to regulate how hot the water throughout the house gets. I can turn it from 120 to 160 degrees. It will make it hotter (a little) but kills the flow. Is it sediment somewhere? Could it be the pump tank? (second photo of blue tank) There is a whole house water filter (just changed filter media) as you can see in the bottom right corner of the first pic. Any advice is greatly appreciated!! Thanks in advance from a noob!

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  2. Dec 6, 2018 #2

    Geofd

    Geofd

    Geofd

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    usually that means your tankless coil is getting clogged this is something a plumber would take care of...another question I have is ….there should be a backflow device...
    it separates the boiler water from your cold water into the boiler in the case of a reverse flow condition....broken water main,fire hydrant in use, the water feeding your boiler needs a backflow device....your tankless (domestic hot water) does not
     
  3. Dec 6, 2018 #3

    wood4d

    wood4d

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    the blue tank has little to do with it. Its for your well even though it is going to be involved in general pressure. you have a tempering valve on your hot water to limit the temp obviously. Your boiler heats your hot water for the house. IMO you need to lose the tempering valve, since your water temp is regulated at the fixtures (or should be). When you increase the temp with the black knob, you are decreasing the amount of cold mixed in which means less water by volume. The theory of using one fixture to satisfy all your needs is a bit outdated when you are on a well with steam oil heat. Not ideal combinations. You should consider adding a separate water heater maybe using propane...it will save you money in the long run since everytime you need hot water you are burning oil.
     
  4. Dec 6, 2018 #4

    voletl

    voletl

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    There is a coil in there that is clogged this coil is where your boiler heats your hot water. Look into indirect water heaters 100% better the the coil you have you will save a ton of oil too. Screenshot_20181206-175740.jpeg
     
  5. Dec 8, 2018 at 10:38 PM #5

    Diehard

    Diehard

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    First off I pretty much agree with the above comments, except for maybe a couple.
    1. You cannot, "...lose the tempering valve...", as it must be present on that type of system as a safety requirement. The boiler's high limit temp setting is usually up around 180 -190 degrees F. (Could be more or less.)
    2. At least in my area, heating your water using propane wouldn't be much, if any savings over oil.
    3. I agree with Geofd's statemt, "there should be a backflow device..", however, I'm not so sure that is what we see in that picture. This leads me into the following questions and comments.

    So I take it you didn't do any of that piping I see in your picture?
    The reason I ask is because the piping looks rather strange to me.
    I have an oil fired boiler for hot water heat with the optional tankless water heater coil, and similar tempering valve, as well.
    Now I know different units are set up differently but I must ask anyway.
    1. I don't see the Stack Controls, which is typically mounted on the boiler side. Is it on another side? It's about a 6"x8" high box that contains the controls for turning boiler on and off as well as controlling the circulator.

    2. I only see one cold water line entering the boiler(where Geofd questioned the lack of a backflow preventer). I had to assume that was the cold water inlet for the domestic hot water since I don't see another one.

    3. Also, it appears that there's what appears to be about an 8" long stub of pipe with a cap on it. I would have thought that would have been the location of the domestic cold water inlet to the heating coil. That would then make that lower penetration possibly for the stack controls.???

    Since I can't see other parts of the boiler, it may be set up differently then what I would expect.


    I think it would help to see all sides of the boiler, to get a better picture of what is going on.

    But like I already agree with, typically the problem is with the tankless coils, getting built up crap and reducing it's efficiency to transfer the heat. Also, the tempering valve itself, is one pain in the butt, in my experience. In addition to not be able to regulate the set temperature very well, particularly since the boiler water has a large temperature differential, it does get corroded and/or coated on the inside. Also, by the sounds of your description, "...good cold pressure but struggle to output hot water", it sounds like the tempering valve may be affecting the actual flow rate on the hot water side.

    Hopefully some of the more experienced guys/gals can comment on my take of the situation.

    EDIT: Another strange sight, to me anyway, is what appears to be the boilers main electrical power coming from a plug on the wall.
     
    Last edited: Dec 9, 2018 at 2:00 AM

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