Great Plains Case Drain & Motor Return Tractor Connection Guide - Manual (Page 5)

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CDMR 08/27/10
Great Plains Manufacturing reserves the right to make changes or to add improvements to this guide at any time without notice or obligation.
Tractor Requirements
Tractors connected to YP Planters and Air Drills must meet the following requirements:
1. LS Closed or PC Closed hydraulic systems with a case drain
connection and a motor return connection. Open Center
hydraulic systems MUST NOT be used.
2. Verify the tractor Hp meets the requirements listed in the
Specification section of the planter or drill Operator’s Manual
before connecting.
Tractors Equipped with Additional Accessories Connected
to Case Drain and/or Motor Return
Some tractors may be equipped with additional accessories that connect to power beyond
connections on the rear of the tractor (i.e. auto steering). If the case drain and motor return
connections are already in use, then tee’s can be installed to add connections.
IMPORTANT!
DO NOT tee case drain into motor return. Case drain must have zero pressure return. Great
Plains warranty will be voided if case drain has been connected and/or teed to a motor
return line. Case drain should only be returned directly to the hydraulic reservoir. The case
drain line must utilize an ISO 16028 coupler that will allow seepage due to thermal expansion
when disconnected from the tractor.
If tractor case drain circuit is filtered, it is necessary to make sure to have a clean filter to
prevent excessive case pressure. High case pressure will cause motor seal failure.
DO NOT connect the fan motor to power beyond pressure. Continuous flow through the
power beyond will deprive the tractor rear differential and pto drive gears of hydraulic flow
and cause damage to the tractor.
Some tractor manufacturer’s have chosen to use the same type coupler for power beyond
load sense lines as for case drain lines. It is very important that these not be confused to
prevent motor seal damage. DO NOT connect the case drain hose to a power beyond load
sense coupler.
Some tractor manufacturer’s recommend running motor return through a tractor SCV return
port. DO NOT run motor return through a tractor SCV return port. Minimum pressure on
most tractor SCV return ports is approximately 250 to 300 psi. Only connect motor return to
a motor return port. Motor return ports allow pressures less than 50 psi, which prolongs
motor seal life.
Failure to use the correct motor return port can cause oil starvation to the transmission
pump and hydraulic charge circuit on some tractors. This is caused when oil is returned into
the differential housing rather than the transmission or hydraulic charge circuit.
Make sure all hydraulic couplers and hose ends are clean before connecting.
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