DraftingDrafting:
Drafting is a skill that is not commonly used in Rohnert Park. While it may not be
commonly used it is important and can come in quite useful when needed. There are 2
ways to draft. The first is when you are setting up for a draft with water still in your tank.
The second is when you are setting up for a draft with an empty tank. We will look at this
method first.
DRAFTING WITH EMPTY TANK:
Step 1. Position the apparatus with the pump panel facing the desired
water source
Step 2. Attach your hard suction and strainer to the suction side of the
pump making sure that couplings on the hard suction are tight
Step 3. Submerge the strainer into the water source making sure that it
has about 12” of clearance from any debris
Step 4. If operating a 2 stage pump make sure it is in Volume so that
no air becomes trapped in the pump. Engage the pump and bring
the engine RPM’s up to about 1000-1200 (If operating a
hydrostatic pump 50-100 psi will be fine) and crack your tank
fill valve (there is no exact science to this practice will give you
a feel for it)
Step 5. Close the tank to pump valve and operate the positive
displacement pump. (While doing this you should see the hard
suction get heavy and visually see water moving up the hose)
Step 6. Once a pressure is achieved on your main pressure gauge release
the primer handle and watch that the main pressure is steady
DRAFTING WITH WATER IN THE TANK:
Step 1. Position the apparatus with the pump panel facing the desired
water source
Step 2. Attach your hard suction and strainer to the suction side of the
pump making sure that couplings on the hard suction are tight
Step 3. Submerge the strainer into the water source making sure that it
has about 12” of clearance from any debris
Step 4. If operating a 2 stage pump make sure it is in Volume so that
no air becomes trapped in the pump. Engage the pump and bring
the engine RPM’s up to about 1000-1200 (If operating a
hydrostatic pump 50-100 psi will be fine) and crack your tank
fill valve (there is no exact science to this practice will give you
a feel for it)
Step 5. While leaving your tank to pump valve open, open up your
suction valve letting water flow down the hard suction. (you
should see air bubbles coming out the strainer in the water).
Step 6. Once all air is gone from the hard suction, close your tank to
pump valve and check for a steady pressure on your main
pressure gauge.
The key to drafting is practice. You have to get a feel for how many RPM’s are needed to
maintain different GPM flow rates.