Great Plains PH-20 Operator Manual - Manual (Page 26)

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Section 3 Adjustments
PH-15, PH-20, PFH-15 and PFH-20 Precision Fertilizer Hitch 148-365M 12/29/2011
Great Plains Mfg., Inc.
The PFH-15 and PFH-20 have 0.048-inch orifices as stan-
dard equipment. You can order the other Tee-Jet orifices
listed on the following chart from your Great Plains dealer.
Many other orifice sizes are available through Tee-Jet.
To choose and install the proper orifice plate:
1. Find your hitch width and row spacing on the chart.
2. Select the largest orifice that includes your application
rate.
Figure 3-11
Orifice Plate
*Orifice-48 is provided as standard equipment with manifold. Orifices of other sizes must be ordered. Contact your Great
Plains dealer.
TIP: When using very low application rates, you may find that the small orifices plug too often. Consider adding water to
your fertilizer and increasing the rate. This will allow you to switch to a larger orifice.
Example: 10 GPA original rate. (1) Mix 200 gallons of fertilizer with 200 gallons of water. Your product is now at half
strength. (2) Double your application rate to 20 GPA. Your ACTUAL fertilizer rate is still 10 GPA.
Orifice-20
0.020 Inch
Great Plains No. 832-052C
Orifice-34
0.034 Inch
Great Plains No. 832-053C
Orifice-48*
0.048 Inch
Great Plains No. 832-054C
Orifice-80
0.080 Inch
Great Plains No. 832-055C
Application Rates, Gallons per Acre
15-Foot Hitches
6-Inch Spacing 4 - 11 9 - 34 20 - 63 50 - 105
7.5-Inch Spacing 4 - 10 7 - 27 14 - 53 40 - 105
8-Inch Spacing 4 - 9 7 - 24 14 - 48 37 - 105
10-Inch Spacing – 4 - 22 12 - 38 30 - 105
15-Inch Spacing – 4 - 14 7 - 27 20 - 80
Twin Row Spacing – 4 - 14 7 - 27 20 - 80
20-Foot Hitches
6-Inch Spacing 3 - 13 10 - 34 18 - 64 50 - 80
7.5-Inch Spacing 3 - 11 7 - 28 14 - 52 42 - 80
8-Inch Spacing 3 - 9 7 - 26 14 - 48 38 - 80
10-Inch Spacing – 4 - 20 11 - 40 30 - 80
15-Inch Spacing – 4 - 14 7 - 26 20 - 73
Twin Row Spacing – 4 - 14 7 - 26 20 - 73
Strainer
A Banjo brand strainer is supplied with the fertilizer pump
option and is to be plumbed before the John Blue pump.
The standard 80 mesh screen should be suitable for most
applications. Other screen sizes are available from Banjo
Corporation. If changing screen sizes, keep in mind the
following.
• A smaller mesh (100) will keep the very small mani-
fold orifice plates from plugging so often. However,
the screen will have to be cleaned more often.
• A larger mesh (50) or (30) will pass more material
but should only be considered when using large
manifold orifice plates.
• A plugged or partially plugged screen will starve the
pump and will result in a reduced application rate.
• John Blue recommends using a 30 mesh screen or
tighter to protect their pump.
• Mesh sizes: (Smallest) 100, 80, 50, 30 (Largest)
Orifice Plates
In general, the orifice needs to be small enough to create
at least 5 psi of pressure in the manifold but large enough
to prevent the manifold pressure from exceeding 85 psi. To
reduce orifice plugging and pump wear, use the largest or-
ifice practical for your fertilizer application rate.