REGULATING HYDRAULIC FLOW TO THE SPRAYER PUMP
FLOW LIMITER
The flow limiter is a hydraulic device designed to shut off the flow of hydraulic oil when a motor’s
rated flow is exceeded. On tractors with LOAD SENSING (LS) Closed Center hydraulic systems,
it prevents failures due to excess flow. These tractors present a great potential to run the motors
beyond their rated speeds. The flows out of the hydraulic valves can exceed 29 GPM while the
motors are rated at 4 to 11 GPM. The flow limiter protects the Ace motor by shutting off when
hydraulic flows exceed the motor’s capacity.
The flow limiter should not be used on OPEN Center or PRESSURE COMPENSATING Closed
Center hydraulic systems. The flow limiter should not be used with a restrictor orifice.
Consult Ace Form # FLOW LIMITER for additional information and specifications.
WARNING: FAILURE TO REGULATE OIL FLOW WILL CAUSE MOTOR FAILURE
There are three general types of hydraulic systems: 1) Load Sensing (LS), also known as
Pressure-Flow Compensating Closed Center, 2) Pressure Compensating Closed Center (PC), and
3) Open Center (OPEN). The flow of hydraulic oil is regulated in a different manner for each type
of hydraulic system. Consult the Tractor Hydraulic System Pump Selection Guide(HSG), Internet
Hydraulic Selection Guide (IHSG) at www.AcePumps.com, or your tractor dealer to determine the
type hydraulic system on your tractor and the method of regulation.
SHUT-OFF PRESSURE
Shut-off pressure is the sprayer system pressure with all flow turned off. This means closing
the boom, agitation, and any by-pass valves. It is the highest pressure a centrifugal pump will
achieve for a given RPM and relates directly to the flow of hydraulic oil. A pressure gauge must
be located between the pump discharge and the shut off valves.
Maximum Shutoff Pressure:
FMC-75-HYD
100 PSI
FMC-150FS-HYD
120 PSI
FMC-HYD
100 PSI
FMC-150SP-HYD
120 PSI
FMC-150-HYD
120 PSI
FMC-200-HYD-210/310
80 PSI
FMC-150F-HYD
120 PSI
FMC-200-HYD-304
120 PSI
LOAD SENSING CLOSED CENTER SYSTEM
Regulate oil flow with tractor’s
FLOW CONTROL
and
FLOW LIMITER
.
(Do not use restrictor orifice.)
Setup Instructions:
1. Suggested: Remove adapter and install flow limiter in motor inlet port (marked
I
).
2. Close motor needle valve: loosen jam nut, screw needle valve clockwise
until seated, and lock jam nut. (factory setting)
3. Shut off sprayer boom and agitation valves.
4. Adjust tractor flow control to minimum flow setting (turtle).
5. Move hydraulic lever to “Lower/Retract” position to start pump.
6. Adjust tractor flow control until sprayer shut-off pressure is below
maximum shown in
SHUT-OFF PRESSURE
section above.
Note: If the flow limiter stops oil flow to the motor: 6a) Move hydraulic
lever to “Float” or “Neutral” to remove oil pressure from the flow limiter.
6b) Adjust tractor flow control to a lower flow position.
6c) Repeat steps 5 and 6.
7. Open the sprayer agitation valve to get desired spraying pressure
.
Flow Limiter
(Optional)
Flow Control
4