1. #1
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    Default Back Flushing the pump

    I'm new here...and was interested in how to back flush a fire pump. I know the concept...putting the water in through a discharge and then it comes out an intake.

    Is this the proper way to do it, or can you put it into just any discharge and it come out any intake?

    My volunteer company is going to do this Friday, and i want to have a heads up.

    Thanks

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    Can anyone help out?

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    Sounds like you already know how to do it!!

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    You pretty much have the concept. You can use any discharge but I prefer one close to the intakes on the side. It works best with a hydrant from the municipal supply. We do not have that luxury and it take another engine at one of our dry hydrants to supply the other and then we switch. Also you can engage the pump but shift the transmission to reverse. BUT ONLY RUN AT AN IDLE!!! Hope this helps.

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    i feel a little ignorant for asking.....but what would the benifits of back flushing the pump be?

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    Quote Originally Posted by peon30 View Post
    i feel a little ignorant for asking.....but what would the benifits of back flushing the pump be?
    It flushes out any debris or other materials that might not go through the impellor well. basically cleans out the pump without sending the stuff through the impellor, nozzles, etc. (ever noticed little pieces of gravel or rock in your nozzle?)

    A lot of times we'll open up both intakes and flush out both sides. Check the operator's manual if you're not sure what they want done. As I remember, Hale recommends back-flushing weekly, plus after anything other than hydrant water is pumped. I'm sure Waterous and Darley are probably similar.

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    Quote Originally Posted by peon30 View Post
    i feel a little ignorant for asking.....but what would the benifits of back flushing the pump be?
    It can also be used when trying to pull the initial draft. You open the valve a bit fil the hose, and start the pump. Just a little something that has worked in days gone by

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    Quote Originally Posted by HotTrotter View Post
    It can also be used when trying to pull the initial draft. You open the valve a bit fil the hose, and start the pump. Just a little something that has worked in days gone by
    We do this for some of our longer draft hydrant sites...mostly ones that have a bit of an incline. Works well.
    The comments made by me are my opinions only, not of the Fire and EMS services I am affiliated with.

    I have lost my mind..has anyone seen it? it's not worth much..but it's mine

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    Ah yes, the tank-to-pump cheat

    I never knew you could put the pump in reverse... i mean, obviously you an put the transmission in any gear you want. But I never would have concidered putting it in any gear other than D.
    Even the burger-flippers at McDonald's probably have some McWackers.

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    Quote Originally Posted by nmfire View Post
    Ah yes, the tank-to-pump cheat

    I never knew you could put the pump in reverse... i mean, obviously you an put the transmission in any gear you want. But I never would have concidered putting it in any gear other than D.
    You can't, or at least you shouldn't be able to. By backpriming you're basically using a valved intake with your tank water. You start flowing the tank water through the discharge, then gently open the intake valve trying not to let more air in than water going out. That will capture a prime for you. It's best to have a full tank of water, then fill your tank back up when you're done.

    Backflushing a pump.
    We start by putting a 2 1/2" connected to a hydrant to the 6" intake, open the other 6" side and start the water. This will flush the main body of the pump. Turn off the water and replace the cap on the open side. Leave the 2 1/2" hooked up. Now open all of the 2 1/2" valves, this will flush the manifold out. No need to open the preconnects as sand will not likely travel up. There, you've just backflushed your pump without putting it in gear. Now if your engine is equipped with a sandbox or cleanout on the tank, you might as well dump that too. Good luck.
    IAFF

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    Your discharges dont have a screen on them like your intakes , so its a good idea to make up a dbl female with a screen on it just in case, also some foam capable discharges have a check valve on them so you may have to use one that is water only.

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    Default Old Guy - See Def. of Kuh Shise in German Dictionary

    Back flushing is recommended any time you work from draft or on a new main.
    Need several questions answered...Single or 2 stage pump. It will make a difference. In a 2 stage pump there are clapper valves that help direct water when pump is in the pressure position and in order to flush the second stage of the pump you will need to remove the screens from both suction intakes, then use a broom handle or other long handle to prop the clappers in the open position. (second stage is usually toward the front - use a light to look up the hole) I also remove intake screens from any pony suctions, rear and or front suctions. Be sure to place the transfer valve in the volume position when you start. In this situation water hammer can be an aid to removing debris from the impeller eye if it has been lodged tightly. You can quickly open the discharge valve where you are putting in the hydrant water, but close it slowly to prevent water hammer in the water system. Clean water is absolutely essential, because you want to remove any sand that has been trapped as well as larger debris. You do not need to put the pump in gear.

    Here is a list of some things I have found after back flushing. Gravel that was not cleaned out of the water mains when they were being installed. Not just a little bit but POUNDS of the limestone bedding material. Numerous 2 1/2" suction strainers. Coal lumps, pieces of 6" intake strainers and a snuff can lid. Pieces of cast iron from hydrant valve assemblies. Lots and lots of sand. even an aluminum soda can crumpled into a tight ball.

    Work your way from the open intakes outward to the pony suctions and finally to the rear and fron suction intakes. It might even be a good idea to flush every discharge backward to be sure everything is clean. While you are at it, try to look over the stuff you get out to be sure that you can identify exactly where or what it came from. The one thing we could not identify turned out to be an expensive pump rebuild...a piece of half circle cast iron that later was identified at part of the pump casting that was used to prevent the "anti-swirl" device from turning on the pump shaft.

    So, good luck with your project and do it in a clean paved parking lot where it will be possible to look at what you have flushed out of your pump.

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    hey, you might even find some useful things in there too!
    Even the burger-flippers at McDonald's probably have some McWackers.

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