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On-Demand Hot Water Not Working as Expected

We just purchased a house which has a Weil-McLain Gold Oil Series High-efficiency Oil-fired Boiler and a Weil-McLain WTGO Series 3 Oil-Fired Natural Draft Water Boiler. I believe these units were purchased in 2010 but we seem to be having hot water issues.

I'm accustomed to long, hot showers. In order to get the water hot, and have it stay that way for more than 10 minutes, I have to raise the thermostat on the house so that the boiler will fire and the water will stay hot. I've also found that I never have to touch the cold water valve at all. The tiniest tweak of the cold water valve will cause the water coming from the faucet to drop considerably in temperature. I have to open up the hot water ALL THE WAY in order to get a comfortable temperature.

The second issue we are having with our hot water is that we don't get any in the kitchen. I can open the hot water in the kitchen and it never even gets luke warm. In order to get hot water, I need to leave it running, run to the bathroom, open the hot water in the bathtub until piping hot, then turn off and go back to the kitchen. It'll stay hot as long as it stays open. If I turn the faucet over to cold or shut off and try again, I will be unable to get hot water.

What could be causing this issue? Is it a simple fix or will I have to call in a professional. I don't know if it makes a difference but we also have well water. Any help will be appreciated.


  • Larry Weingarten
    Larry Weingarten Member Posts: 3,336
    I can only answer...

    ... part of the question.  No hot water at the kitchen might be a plumbing problem rather than an equipment problem.  Try this test for cross connection:  Shut off water supply to the hot side of things.  Then open a hot tap.  It should run for a second or four and then slow and stop.  If it keeps running, cold water is making it's way into the hot side.  Your job is to find the leak and fix it.  It is most likely in fixtures that have a single handle.

    Yours,  Larry
  • icesailor
    icesailor Member Posts: 7,265
    Low Hot Water:

    Look to the shower that you are having a problem with. You probably have a cross connection between the hot and cold water in the potable water system. If the house was built in 2010, it is required to have a single lever shower valve that opens in the cold position and moves to the hot. And be of a "pressure balance" type. It can also be a thermostatic type but it will also be a pressure balance type.

    Do you know what brand of valve you have?

    If you are "handy", take the cover off the shower valve to expose the inner workings. Turn on the shower valve. The left/hot side should get hot. Regardless of how well it is working. When the left side is hot, shut off the shower valve and go turn on the hot in the kitchen sink. Wait a few and go back and feel the hot side of the shower valve. If it is cold, the check valves in the shower valves need to be replaced.

    Or you have anti-sweat valves on toilets and one has a bad check.

    Or you have a washing machine valve with a hot and cold with a "Y" connector to a washing machine that is making a cross connection.

    Sometimes, it takes two people to find it. You have to follow the hot water and see where it is being cross contaminated. That is shown by the fact that you don't get hot water in the kitchen sink.

    Send a photo of the shower valve.