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Oh yeah...I see that the delavan pumps have an 1/2" inlet/outlet,right?Do ya'll just cut and connect the 1/2" to the 5/8" hose?I know that the 5/8" is better,right?Thanks again

 By-pass pumps route the liquid back into the supply tank when the application line is shut off. It eliminates the need for a demand switch because its flowing constantly. A by-pass valve is needed to operate this way.I don't use electric pumps but I've asked in the past why people use the demand switch rather than the by-pass.

Jeff

-- Edited by Raystown Roof Cleaning Central PA 1-800-236-0322 on Monday 15th of March 2010 01:52:12 PM

Does anyone have actual experience with a by-pass electric system?

Jeff

I have a delavan on demand pump that I use for roof cleaning. On demand basically means that when I open the ball valve the pump starts pumping and will shut off when I close the valve. So the pump only runs when the ball valve is open.

I have a 12 volt bypass pump that I use in by biodiesel operation. The pump has an internal bypass. What that means is when I turn the pump on it starts pumping regardless of the nozzle being opened or closed. If the nozzle is closed the biodiesel will circulate within the pump. As soon as I open the nozzle the pump will transfer the biodiesel out of the pump through the hose into my truck tank. The pump runs continously until I shut it off with the pump switch.

12 volt electric pumps usually have a short duty cycle. If you are using a 12 volt pump for roof cleaning I would use an on demand pump. If you use a bypass pump you will probably exceed the duty cycle and run the risk of burning up the pump.

Charles

-- Edited by cweman on Wednesday 17th of March 2010 11:00:37 AM

on demand cool! I'm buying tomorow!