396
-
3815Y1 SureFire PumpRight for Raven RCM
5
5
Revised 01/16/2018
5. “
My pressure is too high / too low.
”
The pressure will be what it is depending on how hard it has to push to get the amount of liquid you
are moving from the pressure sensor to where it leaves the system. This pressure will depend on the
product itself, the volume (gal/min) you are moving and how much restriction there is to that flow. The
orifice or metering tube will be the primary restriction, but it is possible that other parts of the system
may add to the total pressure. The pressure a system develops will be less (possibly much less) with water than it will be
with a fertilizer product.
What pressure is
“
too low
”?
You need enough pressure to open the check valves. If the pressure is too low, some check valves will open before
others, so that some rows may be flowing while others are not.
With 4 lb check valves, we like at least 8 PSI. With 10
lb check valves, we like 15
-
20 PSI.
What pressure is
“
too high
”?
There are a few products that may have flow characteristics that are better at lower rather than higher pressures. With
most products that is not a concern.
The plumbing components of a SureFire system are rated at 100 PSI or above. On an electric pump system, the pump
capacity decreases as the pressure increases. Our standard Tower pump has an internal 70 PSI bypass.
With an
electric pump, we like to see pressures from 10 to 30 PSI.
If the pump has the capacity to hit the rate at higher
pressures, there is not a problem with doing that, but for long
-
term operation it would be best to switch to a larger orifice
or metering tube.
The SureFire PumpRight hydraulic pump has the ability to pump up to 290 PSI. SureFire plumbs these with a 100 PSI
pressure relief valve (PRV) so that plumbing components will not be damaged if high pressure develops.
Typical
operating pressures with hydraulic pumps will be 20
-
60 PSI
, but the pump will work fine at 80
-
90 PSI if that is
needed. If continually running in that high range, consider a larger orifice or metering tube.
Lower pressure will not necessarily reduce the
velocity of the output stream
at the row. Conversely, higher pressure
will not necessarily increase the velocity of the output stream at the row. The velocity of the output stream is determined
by the volume of the flow and the size of the opening at the output. Changing the pressure by changing an orifice or
metering tube upstream from the outlet will not affect the velocity of the output stream if the flow volume remains the
same.
Options if pressure is too high with orifices
: Use a bigger orifice. Slow down. If pressure is too low, use a
smaller orifice.
With metering tube: Options if pressure is too high
: Use a larger diameter tube. Shorten the tubes that are
on now. Slow down. (
The pressure in a metering tube is related to the viscosity of the product. Many products change
viscosity as the temperature changes. A product will have a higher viscosity (and therefore higher pressure) on a cold
morning that it will on a hot afternoon.)
With metering tube: Options if pressure is too low
: Switch to a smaller diameter tube. Use a longer tube.
See SureFire publication
“396
-
3269
Y1 Navigating the Metering Tube Maze
”
for more information on how
metering tube works.
See SureFire publication
“396
-
3229
Y1 Liquid System Components Overview
”
for a description of all the system
components and additional troubleshooting/service information.
See the system manual for your system for more complete information. Manuals and publications are available
for download at www.surefireag.com.
© 2016
-
2018 SureFire Ag Systems
G
Trouble
-
shooting
Read the
for safety information and additional setup/operating information.
SureFire
Ag
Systems
