saimese setup with no unloaders

JBurd

New member
I have a large flatwork project coming up so I have a siamese kit and re-nozzled my surface cleaner, but as I was starting to switch out my unloaders for pressure-trapped ones on my two 5.5gpm hot machines, it occurred to me maybe things would go more smoothly without any unloaders at all. My surface cleaner has a filter and no shut-off valve, so what's the worst that can happen?? Running the flow constantly increases the chances of running out of water but is there any other risks I'm missing?
 
No lot of the old fleet washers would use an open gun an no unloader to keep things simple but i would make sure all cut off valves were taken off because old habit are hard to break an if you cut it off it would be bad real bad.
 
Is it worth risking damage to your pumps? What if you clogged both tips? Or clog your filter??
Think of it this way, your unloader is there for a reason. And if it is dumping water while you are using your SC, then it's dumping for a reason. That reason is that your pumps are not designed to put out that much pressure.
Just my .02
 
It can be done. Just make sure there are functioning pop off valves on the machines in case of stoppage.
 
It can be done. Just make sure there are functioning pop off valves on the machines in case of stoppage.
Russ. What happens if he has what the nozzle charts say is correct for 11 gpms with 200 feet of hose? Doesn't the back pressure from all that hose cause the unloader to bypass a little. Is the water that is usually bypassed, forced down the line without an unloader? Would it be smarter to use nozzles that are larger than the rated specs of the pump to avoid overtaxing the pump? Just asking, I don't know the answer.
 
I'm confused.... Whats the point?

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I'm confused.... Whats the point?

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Whats up Jeremy? Without the unloader bypassing, the pump will get overworked trying to pump all the water down the hose if he has too small of nozzles on there(even if thats what the charts call for). When I hook up my surface cleaner to an 8 foot jumper hose, with the right nozzles on there. I bypass just a drip. When I run 200 feet of hose, the back pressure causes the unloader to kick in, and I bypass probably a half gallon. The hose friction cause back pressure that kick the unloader in. That's why you lose pressure with longer hoses. The unloader bypasses a little which makes the pressure go down.(less water going through the same size nozzles.) To get full flow with a longer hose, I size the nozzles to the pressure at the gun. So if the unloader is set at 3500 psi, but I can only get 2800 psi at the gun because of hose friction. I size my nozzles for 2800. That way you bypass a lot less.
 
Whats up Jeremy? Without the unloader bypassing, the pump will get overworked trying to pump all the water down the hose if he has too small of nozzles on there(even if thats what the charts call for). When I hook up my surface cleaner to an 8 foot jumper hose, with the right nozzles on there. I bypass just a drip. When I run 200 feet of hose, the back pressure causes the unloader to kick in, and I bypass probably a half gallon. The hose friction cause back pressure that kick the unloader in. That's why you lose pressure with longer hoses. The unloader bypasses a little which makes the pressure go down.(less water going through the same size nozzles.) To get full flow with a longer hose, I size the nozzles to the pressure at the gun. So if the unloader is set at 3500 psi, but I can only get 2800 psi at the gun because of hose friction. I size my nozzles for 2800. That way you bypass a lot less.
#PressureWashingScience

My sc has 3 tips. I use 3.5's when running 8.5 gpm. Not sure if this is what you're basically saying but i think so. I was doing it to intentionally drop the pressure without adjusting the unloader though

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#PressureWashingScience

My sc has 3 tips. I use 3.5's when running 8.5 gpm. Not sure if this is what you're basically saying but i think so. I was doing it to intentionally drop the pressure without adjusting the unloader though

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With that you are getting about 2600 psi and full flow.
 
Russ. What happens if he has what the nozzle charts say is correct for 11 gpms with 200 feet of hose? Doesn't the back pressure from all that hose cause the unloader to bypass a little. Is the water that is usually bypassed, forced down the line without an unloader? Would it be smarter to use nozzles that are larger than the rated specs of the pump to avoid overtaxing the pump? Just asking, I don't know the answer.

My understanding is that with flow actuated unloaders...yes a little would be bypassed. But with trapped pressure they are all or nothing so they would cycle open closed. But I could be wrong.
 
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