MacDon 802 Bi-Directional Adapter - Manual (Page 38)

37
HEADER DRIVE RELIEF VALVE
A
C
MAINTENANCE/SERVICE
HYDRAULIC SYSTEM (continued)
FLOW CONTROL BLOCK: Flow control block
provides hydraulic power to the reel and conveyor
drives with flow variable from 5 to 8 gallons per
minute (gpm) to each circuit.
Header Drive Relief Valve: Overload protection for
the reel and conveyor drives is provided by an internal
relief valve (A) in the flow control block.
SICKLE DRIVE PUMP: Depending on the hydraulic
configuration of your adapter, the MacDon header
drive pump or the New Holland auxiliary pump
provides hydraulic power to the sickle drive with 25
gpm flow available in the closed loop.
Sickle Drive Pump Relief Valve: Overload protection
for the sickle drive pump is provided by an external
relief valve (B).
To check and adjust relief pressures:
1. Always attach pressure gauge to a hose that is
long enough to allow gauge to be positioned and
read from the operator's seat.
• For relief valve (A), attach a 3000 psi (21 MPa)
pressure gauge. Connect hose to draper pressure
coupler (C) (male, orange colour code) on adapter.
• For relief valve (B), attach a 5000 psi (34 MPa)
pressure gauge. Remove pressure switch (D) and
attach hose to this port.
2. · Start engine and run at operating speed.
· Engage header drive.
· For relief valve (A), adjust draper speed control
to minimum, so drapers are running slowly.
3. For relief valve (A), pressure should be 2150 to
2400 psi (14.8 to 16.5 MPa).
For relief valve (B), pressure should be 3850 to
4100 psi (26.5 to 28.2 MPa).
If pressures are not within spec, proceed with adjustment or replacement:
4. Disengage header drive. Shut off engine and remove key.
5. To adjust pressure setting:
· Loosen jam nut at relief valve (A) or (B).
· Turn the adjustment screw in 1/4 turn increments, clockwise to increase pressure, counter-clockwise to
decrease.
6. Repeat checking and adjustment until pressure is correct, then tighten jam nut.
IMPORTANT: If relief pressure does not increase after adjusting the screw two or three times, check relief
valve as follows: Remove relief valve from block. Check that no contaminant is preventing the spring-loaded
poppet from properly seating against the valve body. Clean as required, and reinstall valve. Reset adjustment
screw to original position before checking relief pressure.
PTO PUMP RELIEF VALVE
B