Graco Mark IV

1. WatchDog Activated Reset Watchdog

From 311287 rev E, page 34

1. Check transducer or transducer connections 1. Make sure there is no pressure in the system (see Pressure Relief , page 22). Check fluid path for clogs, such as clogged filter. 2. Use airless paint spray hose with no metal braid 1/4 in. x 50 ft minimum. Smaller hose or metal braid hose may result in high-pressure spikes. 3. Set sprayer to OFF and disconnect power to sprayer. 4. Check transducer and connections to control board. 5. Disconnect transducer from control board socket. Check that transducer and control board contacts are clean and secure. 6. Reconnect transducer to control board socket. Connect power, set sprayer ON and control knob 1/2 turn clockwise. If sprayer does not run properly, set sprayer to OFF and go to next step. 7. Install new transducer. Connect power, set sprayer ON and control knob 1/2 turn clockwise. Replace control board if sprayer does not run properly.

From 311287 rev E, page 34

1. Check transducer or transducer connections (control board is not detecting a pressure signal). 1. Set sprayer to OFF and disconnect power to sprayer. 2. Check transducer and connections to control board. 3. Disconnect transducer from control board socket. Check to see if transducer and control board contacts are clean and secure. 4. Reconnect transducer to control board socket. Connect power, set sprayer ON and control knob to 1/2 turn clockwise. If sprayer does not run, set sprayer to OFF and go to next step. 5. Connect a confirmed working transducer to control board socket. 6. Set sprayer ON and control knob to 1/2 turn clockwise. If sprayer runs, install new transducer. Replace control board if sprayer does not run. 7. Check transducer resistance with ohmmeter (less than 9k ohm between red and black wires and 3-6k ohm between green and yellow wires).

From 311287 rev E, page 35

1. Check transducer or transducer connections (control board is not detecting a pressure signal). 1. Set sprayer to OFF and disconnect power to sprayer. 2. Check transducer and connections to control board. 3. Disconnect transducer from control board socket. Check to see if transducer and control board contacts are clean and secure. 4. Reconnect transducer to control board socket. Connect power, set sprayer ON and control knob to 1/2 turn clockwise. If sprayer does not run, set sprayer to OFF and go to next step. 5. Connect a confirmed working transducer to control board socket. 6. Set sprayer ON and control knob to 1/2 turn clockwise. If sprayer runs, install new transducer. Replace control board if sprayer does not run. 7. Check transducer resistance with ohmmeter (less than 9k ohm between red and black wires and 3-6k ohm between green and yellow wires).

From 311287 rev E, page 35

1. Check transducer or transducer connections (control board is not detecting a pressure signal). 1. Set sprayer to OFF and disconnect power to sprayer. 2. Check transducer and connections to control board. 3. Disconnect transducer from control board socket. Check to see if transducer and control board contacts are clean and secure. 4. Reconnect transducer to control board socket. Connect power, set sprayer ON and control knob to 1/2 turn clockwise. If sprayer does not run, set sprayer to OFF and go to next step. 5. Connect a confirmed working transducer to control board socket. 6. Set sprayer ON and control knob to 1/2 turn clockwise. If sprayer runs, install new transducer. Replace control board if sprayer does not run. 7. Check transducer resistance with ohmmeter (less than 9k ohm between red and black wires and 3-6k ohm between green and yellow wires).

From 311287 rev E, page 35

1. Control is commanding motor to run but motor shaft does not rotate. Possibly locked rotor condition, an open connection exists between motor and control, there is a problem with motor or control board, or motor amp draw is excessive. With prime valve open and pressure relieved, start and stop motor 15 times using set point potentiometer (pressure switch). If motor restarts each time at no load, motor may be bad and must be tested (see Step 1). If motor will not restart every time, board is at fault. Replace circuit board. 1. Remove pump and try to run sprayer. If motor runs, check for locked or frozen pump or drive train. If sprayer does not run, continue to step 2. 2. Set sprayer to OFF and disconnect power to sprayer. 3. Disconnect motor connector(s) from control board socket(s). Check that motor connector and control board contacts are clean and secure. If contacts are clean and secure, continue to step 4. 4. Set sprayer to OFF and spin motor fan 1/2 turn. Restart sprayer. If sprayer runs, replace control board. If sprayer does not run, continue to step 5. 5. Perform Spin Test: Test at large 4-pin motor field connector. Disconnect fluid pump from sprayer. Test motor by placing a jumper across pins 1 & 2. Rotate motor fan at about 2 revolutions per second. Acogging resistance to motion should be felt at the fan. The motor should be replaced if no resistance is felt. Repeat for pin combinations 1 & 3 and 2 & 3. Pin 4 (the green wire) is not used in this test. If all spin test is positive, continue to step 6. Green Blue Red Black Green Blue Red Black Green Blue Red Black STEP 1: STEP 2: STEP 3:

From 311287 rev E, page 36

1. Control is commanding motor to run but motor shaft does not rotate. Possibly locked rotor condition, an open connection exists between motor and control, there is a problem with motor or control board, or motor amp draw is excessive. With prime valve open and pressure relieved, start and stop motor 15 times using set point potentiometer (pressure switch). If motor restarts each time at no load, motor is bad and must be replaced. If motor will not restart every time, board is at fault. Replace circuit board. 6. Perform Field Short Test: Test at large 4-pin motor field connector. There should not be continuity from pin 4, the ground wire, and any of the remaining 3 pins. If motor field connector tests positive, replace control board. 7. Check Motor Thermal Switch: Unplug thermal When check is not OK, refer to this column

From 311287 rev E, page 37

1. Control is commanding motor to run but motor shaft does not rotate. Possibly locked rotor condition, an open connection exists between motor and control, there is a problem with motor or control board, or motor amp draw is excessive. With prime valve open and pressure relieved, start and stop motor 15 times using set point potentiometer (pressure switch). If motor restarts each time at no load, motor is bad and must be replaced. If motor will not restart every time, board is at fault. Replace circuit board. wires. Set meter to proper resistance - ti13140a

From 311287 rev E, page 37

1. Allow sprayer to cool. If sprayer runs when cool, correct cause of overheating. Keep sprayer in cooler location with good ventilation. Make sure motor air intake is not blocked. If sprayer still does not run, follow Step 1. NOTE: Motor must be cooled down for the test. 1. Check thermal device connector (yellow wires)

From 311287 rev E, page 38

1. Check the connections. Control is not receiving a motor position sensor signal control knob 1/2 turn clockwise. If sprayer does not run, replace control board. 1. Turn power OFF. 2. Disconnect m-p sensor and inspect for damage. 3. Reconnect sensor. 4. Turn power ON. If error continues, replace board.

From 311287 rev E, page 38

1. Check to see if control board power module is operating at a high temperature. Module is likely too hot or motor is running too hot. 1. Make sure motor air intake is not blocked. 2. Make sure control board is properly connected to back plate and that conductive thermal paste is used on power components. 3. Replace control board. 4. Replace motor.

From 311287 rev E, page 39

1. Pump throat packings are worn. Tighten packing nut/wet cup. If leakage continues, replace packings; see pump manual. Also check piston valve seat for hardened paint or nicks and replace if necessary. Tighten packing nut/wet-cup.
2. Intake valve ball is packed with material Clean intake valve; see pump manual.
3. Pressure setting is too low Turn Pressure Control Knob clockwise to increase pressure.
4. Material is too thick for asmall diameter Hose,orHose is too long. Use larger diameter Hose and/or reduce overall length of Hose.
5. Amp switch is on low setting. (10A or 15A setting) Switch to 16A or 20A setting.

From 3A6342 rev G, page 37

1. Tip is partially clogged Refer to Clear Spray Tip Clog , page 25.
2. Material supply low, orairwas not properly purged during priming. Refill fluid supply. Refer to FillPump(Prime Pump) , page 21. Then Fill Spray Gun and Hose , page 21. Check fluid supply often to prevent running pump dry.

From 3A6342 rev G, page 37

1. Intake valve is stuck to seat. Removefootvalve.Cleanandinspectintake valve.
2. Suction tube o-ring on foot valve is damaged or missing. Replace Suction Tube o-ring.
3. Air in pump Refer to FillPump (PrimePump) , page 21. Then Fill Spray Gun and Hose , page 21.
4. Intake valve is leaking Clean intake valve. Be sure ball seat is not nicked or worn and that ball seats well. Reassemble valve.
5. Pump packings are worn Replace pump packings; see pump manual.

From 3A6342 rev G, page 37

1. Pressure Control Knob is set too low Increase pressure by turning Pressure Control Knob clockwise.
2. Spray tip clogged Refer to Clear Spray Tip Clog , page 25.

From 3A6342 rev G, page 37

1. Displacement pump pin damaged or missing; see pump manual. Replace pump pin if missing. Be sure retainer spring is fully in groove all around connecting rod; see pump manual.
2. Connecting rod assembly damaged; see pump manual. Replace connecting rod assembly; see pump manual.
3. Gears or drive housing damaged. Inspect drive housing assembly and gears for damage and replace if necessary; see pump manual.

From 3A6342 rev G, page 37

1. Multiple electrical issues. See flow chart, page 46.

From 3A6342 rev G, page 39

1. Multiple electrical issues. See flow chart, page 48.

From 3A6342 rev G, page 39

1. Transducer or transducer connection issue. 1. Make sure there is no pressure in the system (see Pressure Relief Procedure , page 18). Check fluid path for clogs, such as clogged filter. 2. Use airless paint spray Hose with no metal braid 1/4 in. x 50 ft minimum. Smaller Hose or metal braid Hose may result in high-pressure spikes. 3. Set sprayer to OFF and disconnect power to sprayer. 4. Check transducer and connections to control board. 5. Disconnect transducer from control board socket. Check that transducer and control board contacts are clean and secure. 6. Reconnect transducer to control board socket. Connect power, set sprayer ON and control knob 1/2 turn clock - wise. If sprayer does not run properly, set sprayer to OFF and go to next step. 7. Install new transducer. Connect power, set sprayer ON and control knob 1/2

From 3A6342 rev G, page 39

1. Transducer connection issue (control board is not detecting a pressure signal). 1. Set sprayer to OFF and disconnect power to sprayer. 2. Check transducer and connections to control board. 3. Disconnect transducer from control board socket. Check to see if trans - ducer and control board contacts are clean and secure. 4. Reconnect transducer to control board socket. Connect power, set sprayer ON and control knob to 1/2 turn clock - wise. If sprayer does not run, set sprayer to OFF and go to next step. 5. Connect a confirmed working trans - ducer to control board socket. 6. Set sprayer ONandcontrol knob to 1/2 turn clockwise. If sprayer runs, install new transducer. Replace control board if sprayer does not run. 7. Check transducer resistance with ohm - meter (less than 9k ohm between red and black wires and 3-6kohm between green and yellow wires).

From 3A6342 rev G, page 39

1. Control board detected voltage surges. Set sprayer to OFF and disconnect power to sprayer. Locate a good voltage supply to prevent damage to electronics.

From 3A6342 rev G, page 40

1. Control is commanding motor to run but motor shaft does not rotate. 1. Remove pump and try to run sprayer. If motor runs, check for locked or frozen pump or drive train. If sprayer does not run, continue to step 2. 2. Set sprayer to OFF and disconnect power to sprayer. 3. Remove motor cover. 4. Disconnect motor connector(s) above motor. Check that connectors are clean. Reconnect connectors. Check that connectors are fully seated and secure. 5. Set sprayer to OFF and spin motor fan 1/2 turn. Restart sprayer. If sprayer runs, replace control board. If sprayer does not run, continue to step 5. 6. Perform Spin Test: Test at large 4-pin motor field connector. Disconnect fluid pump from sprayer. Test motor by plac - ing a jumper across pins 1 & 2. Rotate motor fan at about 2 revolutions per sec - ond. Acogging resistance to motion should be felt at the fan. The motor should be replaced if no resistance is felt. Repeat for pin combinations 1 & 3 and 2 & 3. Pin 4 (the green wire) is not used in this test. If all spin test is posi - tive, continue to step 6. See connections on next page:

From 3A6342 rev G, page 40

1. Motor overheated NOTE: Motor must be cooled down for the test. 1. Keep sprayer in cooler location with good ventilation. Make sure motor air intake is not blocked. 2. Remove motor cover. Ensure fan is securely attached to motor shaft. 3. Check thermal switch connector (yel - low wires) above motor. 4. Disconnect thermal switch connector above motor. Make sure contacts are clean and secure. Measure resistance of the thermal switch. If reading is not correct, replace motor. Check Motor Thermal Switch: Unplug thermal wires. Set meter to ohms. Meter should read the proper resistance for each unit (see table below). - ti13140a

From 3A6342 rev G, page 43

1. Incoming voltage too low for sprayer operation 1. Set sprayer to OFF and disconnect power to sprayer. 2. Remove other equipment that uses the same circuit. 3. Locate a good voltage supply to avoid damage to electronics.

From 3A6342 rev G, page 44

1. Control board is over heating. 1. Make sure motor air intake is not blocked. 2. Make sure fan is securely attached to motor shaft. 3. Replace control board. 4. Replace motor.

From 3A6342 rev G, page 44

1. Excessive current protection enabled Cycle power on and off.

From 3A6342 rev G, page 44

1. Motor not spinning (no current to motor) 1. Set sprayer to OFF and disconnect power to sprayer. 2. Remove motor cover. 3. Disconnect motor control and inspect for damage at connectors. 4. Reconnect motor control. 5. Turn power on. If code continues, replace control board.

From 3A6342 rev G, page 44

1. Control board is over heating. 1. Make sure motor air intake is not blocked. 2. Make sure fan is securely attached to motor shaft. 3. Replace control board. 4. Replace motor.

From 3A6342 rev G, page 44

Motor should spin freely with no binding or excessive cogging. If motor binds or requires excessive force to spin, replace motor. With multimeter, measure the resistance between the following phases: A to B B to C A to C Resistance values should be equal. If resistance values are significantly different from one another (>0.5 Ω), replace motor. Install pump. Install control board. Install top sprayer shroud.

From 3B0070 rev C, page 41

1. Multiple electrical issues See flow chart

From 3A6342 rev G, page 39

1. Multiple electrical issues See flow chart

From 3A6342 rev G, page 39

1. On the OLDER-style Mark IV there is a sleeve spacer in the lower section that the newer ones don't have, and the o-ring that seals the BOTTOM of that spacer is the usual failure point -- ASSUMING the leak is coming from the TOP of the lower housing. If instead it is leaking from UNDERNEATH the seat, that means a gash around the seat in the lower housing (or a bad seat): all the pressure is bypassing the seat through the cut, and no o-ring will fix that. First find WHERE it is leaking. Leak from the top of the lower housing on an older-style Mark IV: replace the sleeve spacer's bottom o-ring (the spacer and its o-ring are an older-Mark-IV design -- confirmed in the manufacturer manual in the Mark IV / Mark V parts catalog, model 248204). Leak from underneath the seat: that is a cut around the seat or a bad seat in the lower housing -- replace the seat / lower housing, because no o-ring holds 3300 PSI against cut metal. The leak-location two-path diagnosis is from the shop, 15 years of repair experience -- not printed in the manual.

From 310643 rev W

1. FIRMLY confirmed by Adam's repair experience AND the Mark IV / Mark V parts catalog (page 16): on the older-style Mark IV (the build that uses the sleeve spacer -- model 16X428) a leak from the TOP of the lower housing is the SLEEVE SPACER (ref 230) and its sealing O-RING (ref 231). That spacer's o-ring is THE failure point for the top-of-housing leak. A leak from UNDERNEATH the seat is a different problem entirely -- a gash around the seat or a bad seat in the lower housing -- and no o-ring fixes that First find WHERE it's leaking. Leaking from the TOP of the lower housing on an older-style Mark IV (the model 16X428 build with the sleeve spacer): the part is the SLEEVE SPACER (ref 230) and its bottom O-RING (ref 231) -- the verified parts list carries the exact catalog numbers (confirmed in the manufacturer manual, Mark IV / Mark V parts catalog, page 16). Leaking from UNDERNEATH the seat: that's a gash around the seat or a bad seat in the lower housing -- replace the seat / lower housing, because no o-ring holds 3300 PSI against cut metal. The leak-location two-path diagnosis is from the shop, 15 years of repair experience -- not printed in the manual.

From 310643 rev W

1. Control board, see page 40. Replace power cord or control board.

From 3B0070 rev C