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Hot Water Confusion

lenster Member Posts: 3
I am a newbie trying to sort out an answer for my hot water and how it is controlled.

1) I recently had my oil service providers technician  tell  me that the thermostat on my Bradford White "water heater" needed to be replaced and that it is easy to do as it is not covered by their service contract.  I agree but with some caveats. The Bradford White was installed apx 8 years ago. Hot water is generated by my boiler (E.F.M.) ( the boiler was my hot water source prior to Bradford White installation) and delivered to the Bradford White (aquastat? indirect?)  The bradford white delivers to wherever it is needed, shower, dishwasher, faucets, etc. ? I have never been able to regulate the temperature on the Bradford White.  Water temp has always been way too hot.

2) The thermostat on the Bradford White ( Apcom WH9 thermostat) has never seemed to have worked.  I cannot get the water temp down below a scald level. There are currently NO wires going to the single heating element.  This suggests to me the Bradford White is merely a holding tank and water temp is controlled by my boiler.  Is this the case?  All wiring diagrams show wires attached to the heating element on the Bradford but dont know if it should be that way in my case.  I called Bradford White and they said that they couldn't help me.  Call a service tech.

3) This suggests that the hot water is generated and controlled by the thermostat on my boiler, a Honeywell, with a High limit and a Lo limit with a differential to be set between them.  Does the thermostat on the Bradford call for the boiler to reheat which seems quite often throughout  the day?  Every hour or so. Does the Bradford send cooled off water to the boiler and its sensor then go off to reheat?

3) Should I just replace the thermostat ( I have a new TOD 59T to replace the Apcom WH9) on the Bradford and just see what happens?  How would this thermostat control water temp to my service areas.  All explanations and help with this are greatly appreciated.  Does that thermostat on Bradford control the outgoing water temps? Then how does it know to get reheated or more hot water?  Confused on this process.  Thanks, Len


  • STEVEusaPA
    STEVEusaPA Member Posts: 6,505

    The thermostat, actually an aquastat, causes the boiler to fire, running the temperature up to its pre set limit. Under the configuration you describe, the tank is just for storing hot water. The problem is you need a Themostatic mixing valve. The hot water needs to be stored at a temp over 120 degrees, then mixes down to a safe temperature. How the so called professional didn't immediately tell you that this must be done, is unfortunate, unprofessional, and potentionally dangerous.

    You didn't quite say how or why this needs to be replaced, but make sure you add the mixing valve


    There was an error rendering this rich post.

  • icesailor
    icesailor Member Posts: 7,265
    Postging Confusion

    This post was posted in two places. I answered it on the Main Wall under "Hot Water Control".

    There's not enough information to what your tank and boiler is piped like.

    Need more information and photos.

    Like I said in the other post on "The Wall". I have done lots of these installs and never had your problem. If you don't have a circulator between the tankless and the tank, it is installed improperly. If the thermostat on the water heater doesn't work, you won't have hot water.

    Post Pictures.
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