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Reserve water capacity

Dylanbennett

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What is the general rule of thumb for reserve water capacity per pump I have 4ss bays with cat 820 pumps just got the wash and have a 300ish gallon water tank that the pumps pull from would like to go smaller and free up some space in the pump room but unsure of how small would be to small
 

OurTown

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Those are odd pumps and a crazy big tank. Do you have really low incoming city water pressure and a small pipe running to the float valve? For soap and wax our setup for a three bay running 3.5 GPM has a 20 gallon hot water gravity feed tank with the float set to about 10 gallons so we have basically a minute of reserve hot water. Our rinse is cold 40 psi city pressure.
 

Dylanbennett

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Those are odd pumps and a crazy big tank. Do you have really low incoming city water pressure and a small pipe running to the float valve? For soap and wax our setup for a three bay running 3.5 GPM has a 20 gallon hot water gravity feed tank with the float set to about 10 gallons so we have basically a minute of reserve hot water. Our rinse is cold 40 psi city pressure.
City pressure runs 50 to 60psi. I do remember the previous owner saying that on the very buisey days he would have to use a hose to help keep the water level up but the hose is on the same leg as the float so I could probably just upgrade the pipe size and float. I know those pumps are about 10 gal/min so I didn't know if there was a tank size based on water usage to maintain a safe water level. I have not tested the flow rate of the incoming city water to determine the ability to maintain pressure with 'x' amount of flow
 

OurTown

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What pressure and tips are you running? I really doubt you are putting out 10 GPM.
 

Dylanbennett

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2508 tip at 1000psi. I don't expect to be at 10gal/min but I like to plan worst case scenario
What pressure and tips are you running? I really doubt you are putting out 10 GPM.
2508 tip at 1000psi. I don't expect to be at 10gal/min but I like to plan worst case scenario
 

OurTown

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That is about 4 GPM. There must be an undersized float valve or supply pipe.
 

Dylanbennett

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So I'm way over sized on my holding tank. Wonder why. Previous owner said it was all that way when he got it 12 years ago crazy to think it was all for no reason
That is about 4 GPM. There must be an undersized float valve or supply pipe.
 

MEP001

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The static pressure may be 50-60 PSI, but I'll bet it drops to almost nothing with things running, or the valve to fill the 300 gallon tank is way too small. Are you sure that tank is for regular water for those pumps and not the spot free?
 

Dylanbennett

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The static pressure may be 50-60 PSI, but I'll bet it drops to almost nothing with things running, or the valve to fill the 300 gallon tank is way too small. Are you sure that tank is for regular water for those pumps and not the spot free?
Yes it's just regular water we don't have spot free yet. Il have to open the valve all the way and see how much the pressure drops
 

2Biz

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What size is your incoming water supply pipe and size of your float valve that fills the tank? I have 4ss bays with 10gal hot/cold gravity tanks. 2" main, 1" meter and plumbing. No big holding tank. And no issues.
 

2Biz

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1" piping should get you in the neighborhood of 40gpm with no restrictions.
 

MEP001

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FWIW my water pressure stays at about 60 PSI, and the tank for my 6-bay is supplied with a 3/4" stainless braided water heater hose, probably 1/2" ID. It's always been more than sufficient.

I was saying open the hose that's on that same water circuit as the float valve all the way and monitor the pressure drop
If the hose on the same circuit can fill the tank, the restriction must be on the valve meant to keep it full. If you have sufficient and consistent pressure, you shouldn't need more than about 15 gallons of storage.
 

Dylanbennett

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Thanks guys. Must just have an undersized float valve then. With the float valve and a hose on the same circuit wide open I sill have 48psi of water pressure.
 

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Thanks guys. Must just have an undersized float valve then. With the float valve and a hose on the same circuit wide open I sill have 48psi of water pressure.

Can you tell what size it is? Maybe it has a restriction in it. Is there a mesh strainer in line that might be clogged?
 

2Biz

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Don't rule out Galvanic Corrosion in the incoming water supply. Make sure you don't have dis-similar metals connecting any of the plumbing...Shortly after I bought my wash, I changed out the 2" meter that was attached to the incoming copper piping with cast iron flanges...The 2" pipe was closed off to the size of a dime at the flanges on the meter! Lucky for me I decided to save $$$ on my monthly bill by going from a 2" meter to a 1" meter....I was paying a minimum of 33,000 gallons a month with the 2"....Dropped to 6600 gallons minimum with the 1"....Finding the effects of the galvanic corrosion was an added benefit that would have definetly bit me in the a$$ down the road!
 
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