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Very little hot water

wheelbd
wheelbd Member Posts: 6
Hi y’all, hope everyone is doing fine with virus running around. I have a OM-180 with infloor heating and a storage tank for hot water. They changed the tank and I’m not sure the thermostats are wired correctly. If you try to run a tub for a bath I get maybe 3 gallons hot water then goes cold. It’s a little better for a shower, thinking that’s because of the decreased flow. It was fine until the tank was replaced. I live in remote Alaska and sad to say but the plumber we had passed away. Any help would be greatly appreciated.

Comments

  • psb75
    psb75 Member Posts: 350
    You'll need to provide quite a bit more information. A simple schematic of your system, and/or good photos will also help. Is this a Toyotomi OM-180 oil-burning, on-demand unit? Is it an OPEN system with both domestic hot water tank AND in-floor heating? That would not be good.
  • HVACNUT
    HVACNUT Member Posts: 3,906
    @psb75 was right with the Toyotomi I guess. Had to Google the model number to see if there was a boiler that matched that number.

    Anyway, I'm not familiar with Toyotomi but they look pretty simple.

    What's the temp setting on the tank?

    Check the dip switches on the board. Factory settings are for an 18° Delta T. Make sure it wasn't changed to the lower setting.

    If it's used for heat and DHW, its possible the plate HX is scaled and needs to be back flushed.
  • psb75
    psb75 Member Posts: 350
    It's just an on-demand water heater. This poster has a "Tank and infloor radiant." Open system?? For sure there is scaling going on.
  • rick in Alaska
    rick in Alaska Member Posts: 1,178
    That heater will make hot water all day long. There is something piped and or wired wrong for sure. If you can show us a piping and wiring diagram, that would help. Pictures if possible.
    Rick
  • wheelbd
    wheelbd Member Posts: 6
    When your talking about plate HX do you mean the heat exchanger mounted on the tank? To get to my location you have to take a boat or a plane, and with the Coronavirus I cannot even get anyone here if I wanted to🤬 I appreciate your help.
  • wheelbd
    wheelbd Member Posts: 6

  • rick in Alaska
    rick in Alaska Member Posts: 1,178
    I can't tell by the picture, as it is a little grainy, and too much stuff in the way, but it looks like the hot and cold on the water heater are reversed.
    Rick
    mattmia2
  • mattmia2
    mattmia2 Member Posts: 2,860

    I can't tell by the picture, as it is a little grainy, and too much stuff in the way, but it looks like the hot and cold on the water heater are reversed.
    Rick

    That would be my guess unless for some reason there is a pressure gauge on the dhw. I can't trace that plumbing at all, but i assume the gauge is to monitor the well pump and is on the cold water from the well.
  • wheelbd
    wheelbd Member Posts: 6
    Yes the gauge is for the incoming water, we don’t have well the water is gravity from 300 feet up the mountain. No well pump needed. I can try to get a different picture.
  • mattmia2
    mattmia2 Member Posts: 2,860
    What is the pump and tank in the middle for if it isn't a well tank?

    Can take a picture between the water heater and that tank of where the pipes heading down go? That will let us figure out what should be inlet and outlet to the tank.
  • Zman
    Zman Member Posts: 6,537
    This looks like a pretty straight forward indirect setup using a plate heat exchanger. By using an electric water heater for storage, you have the electric option for summer and backup. It does look like they piped the hot and cold backwards when they installed the tank.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • wheelbd
    wheelbd Member Posts: 6
    The pump and tank are there if our pressure drops low we can use it to increase the pressure.the line hooked to the cold side goes directly under the house.
    Thanks guys I appreciate all your help.
  • mattmia2
    mattmia2 Member Posts: 2,860
    Is the line under the house the hot supply? It is important that the cold connect to the cold tapping and the hot to the hot tapping because the cold has a dip tube that directs the cold water to the bottom. Without that the cold water will fall to the bottom from the hot tapping and be picked up by the dip tube in the hot supply leaving most of the tank full of hot water but you getting cold water out of the tank. i think the heat exchanger from the boiler is before the tank.
  • rick in Alaska
    rick in Alaska Member Posts: 1,178
    Definitely from what we can see, you need to swap the lines from the hot and cold on top of the tank. That should solve your problem.
    Rick
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