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  1. #1
    dlc
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    thanks for all the answers from my previous questions. my next question is when your hooked to the hydrant, pumping just 1 handline. when the nozzelmen shut the line down for a few minutes, what happens to the pressure coming from the hydrant, does it just get spun up in the pump and recirculated? Or when you hook up to the hydrant but not need the water yet, the intake valve is opened and water enters the pump and as you wait for the call for water, the pressure coming in will still be greater than the re-circulator can recirculate?


  2. #2
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    When the pump is attached to the hydrant, but not flowing water, the pump will continue to build pressure in the line, but no water will be flowing. As a result, the energy that the pump is putting into the water will become heat in the water. This will damage the pump over time. A small amount of water needs to be flowing in order to cool the pump. Depending on the situation, you can close the intake and re-circulate tank water, or just open the tank fill valve and let the tank overflow.

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    Quote Originally Posted by Eng34FF View Post
    "...the energy that the pump is putting into the water will become heat in the water. This will damage the pump over time.
    Not very much time, either. With a single stage pump, in hot weather, minutes.

    Quote Originally Posted by Eng34FF View Post
    A small amount of water needs to be flowing in order to cool the pump. Depending on the situation, you can close the intake and re-circulate tank water, or just open the tank fill valve and let the tank overflow.
    You don't have to have a whole lot flowing/overflowing. Just enough to dissipate the heat buildup. Keep checking the buildup by putting your hand on the steamer inlet. If it's warm there, it's warmer at the impeller(s).

  4. #4
    Forum Member FIREMECH1's Avatar
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    The Chief nailed it. It only takes a few minutes to overheat a pump when it is dead headed. Meaning there is no water movement in the pump, except inside its self, and all other discharges are closed, including the tank fill/recirculate valve. Even with the hydrant open and intake open, you're still dead heading it. It's making pressure and heat, yet no place for it to go.

    You have a couple choices when the nozzleman closes his line. You can open the tank fill if the hydrant is open as well as your intake. If either the intake is closed, or the hydrant is shut, then you have no choice but to throttle down a bit, and open the tank fill/recirculate valve. Another choice would be to open the drain valve on the discharge of the line that is out. This will also allow cool water in, and prevent any heat build up. I don't suggest this in the winter though.

    FM1
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    Quote Originally Posted by EastKyFF
    "Firemens gets antsies. Theys wants to goes to fires. Sometimeses they haves to waits."

  5. #5
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    Very true on single stage pumps... I tell you my engines pump can heat water fast than our stove can. Give it 15 min or so with just tank water and the whole 850 gals in the tank is warm. Now add in the Southwest Arkansas summer heat you better look out. For this reason I keep the hydrant,intake open and crack the tank to pump allowing the cold water from the main to flow into pump.

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    you can also hook up a short length to one of the discharges and throw it into a ditch or towards a storm drain and crack it a little so you always have some water flowing. This lets you also control where the water goes, instead of the over flowing tank fill.

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