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Thread: Hobart UW50

  1. #1
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    Hobart UW50

    I'm now working at a university, chilled water systems, boilers, etc, and with it comes commercial kitchen equipment. I'm having kind of a hard time with the kitchen as it's new to me. The Hobart is steam heated with 20 kw electric supplemental heat for rinse cycle. Boards were changed, heat strips, etc, I came in during all this, but still, I'm not sure of sequence, new guy, so I watch mostly for now. Original issue was low temp on rinse cycle. Is the supplemental heat supposed to come on when you first turn it to the 2/4/6 minute cycle? It's coming on before the start button is pushed, thus no water moving over the strips, doesn't seem right. More issues, but I'll stop there. Is there anywhere that I can get real troubleshooting manuals/sequence of operations beyond the manuals that come with the units? Great place, better people, just a little frustrated.

  2. #2
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    A steam heated washer with an electrically heated BOOSTER? That's an unusual setup.

    The "supplemental" heat you're referring comes from what's called a booster heater. A booster heater is designed to take incoming water that's already heated (either 140° or 110° - depending on how it was speced) and rapidly heats it to >180° minimum for final rinse.

    A booster may be internal or external of the machine...depending on the machine's design. When designed with an internal booster, earlier UW50 machines were rated to 14kW. Later ones were 15kW.
    The parts manual doesn't include one for 20kW. Is your booster heater possibly an EXTERNAL one? If so, then we'd need its make, model & serial number. Maybe a Hatco or a Lochinvar. Hobart never made EXTERNAL electric booster heaters. Just gas or steam heated.

    Nonetheless, the booster heater (whether internal or external) should ALWAYS be at its designed output temperature (>180°) by the time the pan washer has filled and ready for a wash cycle.

    The WASH tank is heated to 150° once the unit fills and satisfies a float switch (Reed-type). The booster operates to its designed temp I've already mentioned. BOTH should have achieved their settings by the time the machine has filled and wash tank temp setting is met.

    The 2/4/6 settings you referred to are merely an operators selection of how much time in minutes that the WASH cycle operates. The RINSE time is always the same - @ 24 seconds.

    Operational sequence is straight-forward. WASH aggressively cycles the 150° wash tank water through the WASH arms per the wash timer's setting. That's followed by the 24 second rinse through a solenoid valve that supplies the rinse arms.
    THAT water is pushed through there by your building's water supply pressure, but is reduced to a preferred 15-25psi (20psi desired) by a PRV.

    I hope this helps.
    Last edited by ECtofix; 05-17-2019 at 09:31 PM.
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  3. #3
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    Quote Originally Posted by bover View Post
    It's coming on before the start button is pushed, thus no water moving over the strips, doesn't seem right. More issues, but I'll stop there. Is there anywhere that I can get real troubleshooting manuals/sequence of operations beyond the manuals that come with the units? Great place, better people, just a little frustrated.
    With what I said, I'm hoping you'll understand what the machine actually does.

    I'm a little confused though. Your comment I've highlighted in RED doesn't make sense to me.

    MANUAL? Unfortunately, Hobart's service manuals are proprietary. Otherwise, here's an instructions manual:
    https://resources.itwfeg.com/sites/r...ion/F18241.PDF

    Here's a parts manual:
    https://resources.itwfeg.com/sites/r...F18243J_lk.PDF

    Here's a manual that Hobart put together for Krogers' technicians. It's not a service manual and is restricted to only the machine specifications that Krogers uses...but it might help you:
    https://resources.itwfeg.com/sites/r...l%20Manual.pdf
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  4. #4
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    I'll add only one more thing until you can provide more info:

    The UW50 is an odd setup in that it's generally wired to control when its internal OR external booster heater is turned on. If you get to work on other dish machines, you'll get what I mean by that.

    ANYWAY...if you're not getting proper rinse temperature...and it's heated by by a 20kw element, then I'd be taking a closer look at the element. Does it have power? Does it have proper amp draw?

    The ELECTRIC BOOSTER HEATER's control output from the machine can be referred to on page 28 of that Krogers manual I shared.
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  5. #5
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    Thread Starter
    I think your'e correct on the heat strip. I assumed they were 20 kw I guess, I never saw the packaging, but it is an external add on, and they (2) did pull an amp draw.
    With power off, lights are off, all normal. With power 'on', you turn the selector switch to 'fill', the contactor pulls in simultaneously, heat strips become energized, with no water entering. This is before the 'start' button has been pushed. Push fill and it starts filling. I guess what's troubling is that if that's correct it messes with my logic, I just want to learn it

  6. #6
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    Quote Originally Posted by bover View Post
    I think your'e correct on the heat strip. I assumed they were 20 kw I guess, I never saw the packaging, but it is an external add on, and they (2) did pull an amp draw.
    With power off, lights are off, all normal. With power 'on', you turn the selector switch to 'fill', the contactor pulls in simultaneously, heat strips become energized, with no water entering. This is before the 'start' button has been pushed. Push fill and it starts filling. I guess what's troubling is that if that's correct it messes with my logic, I just want to learn it
    Okay, I get ya.

    That contactor merely serves to supply main power to the external booster. Of course, the booster has a thermostat that will allow it to heat to setpoint.

    As for having to push START after you've set the selector switch to FILL? What you're seeing is normal operating procedure for that machine. Check this attached file:
    Attached Images Attached Images
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    "You never know what others don't know." -

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