Graco NOVA - Pressure Control Repair; Motor Control Board Removal; Motor Control Board Installation; Motor Control Board Diagnostics

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Pressure Control Repair
Motor Control Board
Removal
Refer to Fig. 7.
1.
Relieve pressure; page 4.
2. Remove four screws (18) and cover (39).
3. Disconnect at motor control board (35):
 Four motor leads: two yellow, black (+) and
red (–).
 Lead (D) from potentiometer.
 Lead (E) from transducer.
4. Remove five screws (36) and circuit board (35).
Installation
1. Clean pad on rear of motor control board. Apply
small amount of thermal compound 073019 to pad.
2. Fig. 7. Install motor control board (35) with five
screws (36).
3. Connect to motor control board (35):
 Lead (E) to transducer.
 Lead (D) to potentiometer.
 Four motor leads: two yellow, black (+) and
red (–).
4. Bundle and tie all loose wires.
5. Install cover (39) with four screws (18).
Motor Control Board Diagnostics
Note: Keep a new transducer on hand to use for test.
CAUTION
Do not allow sprayer to develop fluid pressure with-
out transducer installed. Leave drain valve open if
test transducer is used.
1. Remove four screws (18) and cover (39).
See Fig. 7.
2. Turn ON/OFF switch ON.
3. Observe LED operation and reference following
table:
4.
Relieve pressure and un-
plug sprayer before servic-
ing control board; page 4.
LED
BLINKS
SPRAYER OPERATION
INDICATES
WHAT TO DO
Once Sprayer runs Normal operation Do nothing
Two times
repeatedly
Sprayer shuts down and LED
continues to blink two times
repeatedly
Run away pressure. Pres-
sure greater than 4500 psi
(310 bar, 31 MPa).
Replace motor control board.
See preceding Motor control
board removal procedure.
Three times
repeatedly
Sprayer shuts down and LED
continues to blink three times
repeatedly
Pressure transducer is
faulty or missing
Check transducer connection.
Open drain valve. Substitute
new transducer for transducer
in sprayer. If sprayer runs,
replace transducer.
Four times
repeatedly
Sprayer shuts down and LED
continues to blink four times
repeatedly
Line voltage is too high Check for voltage supply
problems
Five times
repeatedly
Sprayer shuts down and LED
continues to blink five times
repeatedly
Too much current Check for locked rotor, worn
motor brushes, or shorted
wiring or motor. Repair or
replace failed parts.