House water pressure - volume

Tally Roof Cleaning

Tally Roof Cleaning

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I bit the bullet and I'm adding on residential flat work to go along with the roof cleaning biz (sidewalks-driveways). I went with a 3700 psi, 4 gpm, 13 hp Honda and a 20" Hammerhead. My question is ... will normal house pressure starve the pump or will it be fine. I just don't want to burn up the freek'in pump.
 
Ed Thompson said:
You need to have the correct unloader or the pumpwill not draw from gravity. An untrapped unloader? Not 100% which one, but I just went through this issue and I had to replace the unloader for it to work.
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That is very interesting Ed, can you tell us more, where you got the unloader and the model? I have not heard of that situation before.

Usually the pumps that are direct drive will not pull from a buffer tank (the pump spins too fast) but there are some direct drive pumps out there that will pull from a buffer tank and nothing has ever been said about the unloaders being part of the problem or solution.

Usually all of the gear drive and belt drive pumps will pull from a buffer tank from what I have heard and seen.

Russ J. and I think Paul K. know which direct drive pumps will pull from a tank, give them a call to make sure.


You just never know with residential and commercial locations, I have had a lot of both that could not supply 1 machine and then had some that could supply 2 machines at the same time, it is always a good idea to check the water flow when looking at the property so you know.
 
I run 2my machines at the same time on residential spigots and rarely have any problems. Sometimes I have to put their water softener on bypass but that's about it. I' be never had a buffer tank. Both machines are 4 gpm.
 
Christopher said:
That is very interesting Ed, can you tell us more, where you got the unloader and the model? I have not heard of that situation before.

Usually the pumps that are direct drive will not pull from a buffer tank (the pump spins too fast) but there are some direct drive pumps out there that will pull from a buffer tank and nothing has ever been said about the unloaders being part of the problem or solution.

Usually all of the gear drive and belt drive pumps will pull from a buffer tank from what I have heard and seen.

Russ J. and I think Paul K. know which direct drive pumps will pull from a tank, give them a call to make sure.


You just never know with residential and commercial locations, I have had a lot of both that could not supply 1 machine and then had some that could supply 2 machines at the same time, it is always a good idea to check the water flow when looking at the property so you know.
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We have switched all our unloaders out to K-7's. These unloaders are a little tricky to get set but they totally unload the system. You can even unlatch your quick connects when in bypass. Saves hoses, ends, quick connects and all our equipment from constant banging high pressure. Call Tom from ACR he can hook you up.
 
His point James was that the unloader itself allowed the direct drive pump to pull from a buffer tank when it would not pull from a buffer tank before changing out the unloader.

I have not heard about this before so I was asking to learn more about it.
 
Im def not an unloader expert. I recently wanted to add a 4gpm direct drive alongside an 8gpm on my commercial truck. My guy said he may or may not have to change the unloader. Turned out to be true. Not sure what he replaced it with cuz I wasnt there at the time. I never asked him the specifics. The unit sat right below in front of a 275 gal tote and would not draw. It drew after he change the unloader but it still didnt run right. It cavitated a bit and the hose hummed, not a true 4gpm @ 3500, so I took it out. I think he mentioned installing an untrapped unloader. I unfiled the situation from my memory, it was a few months ago. It was a BE machine with a Comet pump.
 
I had a 13hp 4gpm direct drive that would pull from a buffer tank, when I upgraded to a 18hp 5.5gpm direct drive it would not prime from a buffertank, so I have to take the water supply hose end and go in the tank with it and shoot water into the bulkhead to prime. If I keep water in the buffer tank then I do not have to prime it.
 
Larry Millette said:
I run 2my machines at the same time on residential spigots and rarely have any problems. Sometimes I have to put their water softener on bypass but that's about it. I' be never had a buffer tank. Both machines are 4 gpm.
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So you have been doing it wrong all these years?
 
Ed Thompson said:
Im def not an unloader expert. I recently wanted to add a 4gpm direct drive alongside an 8gpm on my commercial truck. My guy said he may or may not have to change the unloader. Turned out to be true. Not sure what he replaced it with cuz I wasnt there at the time. I never asked him the specifics. The unit sat right below in front of a 275 gal tote and would not draw. It drew after he change the unloader but it still didnt run right. It cavitated a bit and the hose hummed, not a true 4gpm @ 3500, so I took it out. I think he mentioned installing an untrapped unloader. I unfiled the situation from my memory, it was a few months ago. It was a BE machine with a Comet pump.
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I am guessing that he took out some restrictions in the flow to the unit because I doubt the unloader could help it pull from a tank if it is not designed to.

Russ J. or Paul K. can help out here, they will know.

Ed, post the model of your pump here and they can tell you if it is designed to pull from a tank or not.

Russ J. and Paul can sell you a pump that will pull from a tank to put on your rig if you need it, might help out on some jobs if it would work for you.

I was thinking about getting one so I could have a helper rinse besides pulling hoses and other small jobs.
 
Connor said:
I had a 13hp 4gpm direct drive that would pull from a buffer tank, when I upgraded to a 18hp 5.5gpm direct drive it would not prime from a buffertank, so I have to take the water supply hose end and go in the tank with it and shoot water into the bulkhead to prime. If I keep water in the buffer tank then I do not have to prime it.
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Connor, it might just be a height issue, you might need so much water in the tank for it to prime maybe.

A lot of us don't like to haul full tanks of water around, especially when driving out on the highway, saves a little on the fuel bill.

I have a 2" dump valve on the tank so I can empty it before going out of town or coming back but i have a 1" pvc ball valve before the filter screen going to the pump that I close to keep water in the line to the pump before I empty the tank.

Maybe you need 2' or more of water in the tank and it will prime on it's own or if you are running the tank down at the end of a job and not using that one pump, get a 1" pvc ball valve before the filter/strainer to that pump so you can block it in with water going to the pump and only open it when you have X amount or feet of water in the tank and maybe it will keep the prime all the time? It might work for you.
 
Where i live in ames i can pressure feed my 5.5gpm. However there are neighborhoods in Dsm that starve my 4 gpm machines. I've also never heard of a 4 gpm that can be gravity fed. I have heard that in order to flood a pump inlet you want the plumbing to be 2x the diameter of the pump inlet. So if you have a 1 inch inlet, you want 2" pvc feeding it, and of course a decent amount of water in the tank.
 
JBurd said:
Where i live in ames i can pressure feed my 5.5gpm. However there are neighborhoods in Dsm that starve my 4 gpm machines. I've also never heard of a 4 gpm that can be gravity fed. I have heard that in order to flood a pump inlet you want the plumbing to be 2x the diameter of the pump inlet. So if you have a 1 inch inlet, you want 2" pvc feeding it, and of course a decent amount of water in the tank.
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There have been many guys that are gravity feeding their 4gpm pumps, you have to have the right one, contact Russ J and he can sell you the pump that is direct drive that will pull from a tank. Most of the direct drive pumps spin too fast to pull a good vacuum so that is why they come with garden hose connections so it is somewhat pressure fed from the house pressure (city water pressure which is from 30 to 70psi) and keep fed when running.

Contact Russ J at Southside equipment and he will explain it to you better than I could.
 
Connor said:
Chris,

I dont use a very big buffer tank. Even with it full it will not prime if it was completely emptied before hand. see picView attachment 19620 of my set up. I might try increasing my hose diameter.
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Connor, get the model number and give Russ J at Southside equipment a call and see if that pump can pull from a tank, since it is direct drive it might not be able to, a lot of direct drive pumps will not but some will.

If it will pull from a tank then you need to make some changes.

From your picture your pump inlet is almost 1/3 up the height of the buffer tank. The supply hose looks too small, looks like 3/4".

Since your machine is up about 3" with the elevated pump base and then with the direct drive raising the pump higher, that will be a problem for the pump unless the tank is at least 1/2 full or mostly full.

I would get a frame, pallets or something strong and raise the buffer tank up at least 1 foot or higher.

I would run 1" hose from the tank to the pump and put a pvc ball valve to block the supply line at the tank going to the pump but I would remove the filter on the wall, get a 1" filter and put it between the tank and the pump, being on the supply line you could be slowing down the flow to the tank, the pump will pull from the tank and filter easily but you need a good supply to the tank so you don't starve or cavitate the pump.

Do you have a hudson valve in the tank to stop the water when it gets full?

If after talking to Russ J and he varifies that the pump can pull from a tank, things would be easier for your pump if the tank was elevated (the inlet of the pump should be lower than the outlet of the water tank so gravity does most of the work before the pump's suction starts.

That looks like a small tank, I would not empty it between jobs, only for freezing temps, not worth the hassle of blocking valves and opening them all the time.

So, call Russ, get a 1" line from the tank to the pump with a ball valve and 1" filter, raise the tank higher, remove the filter to the tank and if the pump is designed to pull from a tank, then that should eliminate most of your pump problems.
 
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