Thread: 2.5 outlet gpm?

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    Default 2.5 outlet gpm?

    Our department just upgraded to 4" LDH. I am curious to the gpm that is possible out of a 2.5 discharge at the pump panel. I've heard that you can only get "2.5 = 250gpm" for the hose rating but surely you can get more from the dicharge than that. I would like to see one of the discharges converted to a 4" Storz. Any one know any of the specs for this?

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    You can get much more than 250gpm, but the exact amount for your truck can only be determined by a flowmeter. Too many factors such as bends/ restrictions in the piping, pump condition, etc.

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    Like Scooby14b said, you can get more out of the discharge. Look at what you get out of your deckgun at a pump test. You are usually running capacity of the truck out of a two inch tip (or less). What is behind the panel makes a difference, just like the multiple hoses supplying the deckgun.

    You could get all worried about it but your discharge will supply 4".

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    It depends on the plumbing from the pump to the panel and the size of the discharge valve. If it is a 2-1/2" standard valve with a 2-1/4" opening you could expect to get about 600 gpm before the friction loss really rises. If is a 2-1/2" valve with a full 2-1/2" opening or a 3" valve you could probably get 1000 gpm or more before the friction loss rises. Most deck guns/monitors are plumbed with a 3", 3-1/2" or 4" valves and are able to flow capacity of the pump.

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    It seems that most of the trucks that I have pump tested that about 550 to 600 GPM is "normal" for most trucks. Like everyone else noted, it depends alot on what is behind the pump panel. One of our local departments pumps into 4" with no problems.
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    Based on past testing when we migrated over to LDH years ago. On our first out Engine we had a 3" discharge that was tested and flowed a full 1000gpm without having to overwork the pump. That Engine got a 4" stortz adapter on the discharge. The second out Engine was a little older and had 2.5" discharges. Testing showed that a single discharge was only giving us about 700gpm and that required really pushing the pump. On this Engine we preconnected one end of a short pony line of 2.5" from one discharge and the other end to a gated wye (2/2.5"x4"). The folded line and wye were strapped to the running board below the pump panel. This setup allowed for a quick hookup to supply the LDH and get water moving, once the first line was charged a second line could be added to the wye to fill out the 1000gpm target we were shooting for. This setup also allowed for a lower pump pressure which helped to prevent pressure spikes when the line was shutdown at the recieving end suddenly and the relief valve was slow to open. This was alot cheaper than repiping/valving the pump. You may be able to look around your area to find a dept that has gone from 4" to 5" and has a wye laying around unused for cheap.

    Good luck.

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    We have been using 5" LDH since the mid 80's. Our old engine has 2.5" "full flow" valves. When we supply our ground based monitor with 5" from a 2.5" discharge with a Storz adapter we get almost 900 gpm with it (per flow meter). Our new engines have a 3" discharge with built in Stortz connection and we get over well over 1000gpm.

    Dave

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    Originally posted by tribe9a
    Based on past testing when we migrated over to LDH years ago. On our first out Engine we had a 3" discharge that was tested and flowed a full 1000gpm without having to overwork the pump. That Engine got a 4" stortz adapter on the discharge. The second out Engine was a little older and had 2.5" discharges. Testing showed that a single discharge was only giving us about 700gpm and that required really pushing the pump. On this Engine we preconnected one end of a short pony line of 2.5" from one discharge and the other end to a gated wye (2/2.5"x4"). The folded line and wye were strapped to the running board below the pump panel. This setup allowed for a quick hookup to supply the LDH and get water moving, once the first line was charged a second line could be added to the wye to fill out the 1000gpm target we were shooting for. This setup also allowed for a lower pump pressure which helped to prevent pressure spikes when the line was shutdown at the recieving end suddenly and the relief valve was slow to open. This was alot cheaper than repiping/valving the pump. You may be able to look around your area to find a dept that has gone from 4" to 5" and has a wye laying around unused for cheap.

    Good luck.
    Tribe,

    You might try using a clappered siamese for this, it would be less labor intensive unless i've misunderstood exactly what you are doing.

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