Airless Paint Sprayer Trouble-Shooting, Problems & Solutions

Airless Paint Sprayer Trouble Shooting Guide

Problem	Cause	Solution
There is spitting from the gun.	1. The fluid supply is low or empty.	Refill the supply container.
	2. Air entrapped in the fluid pump of the hose.	Check for loose connections on the siphon assembly, tighten, then reprime pump.
Paint leaks into the wet cup.	1. The wet cup is loose.	Tighten just enough to stop leakage.
	2. The throat packings are worn or damaged.	Replace the packings.
	3. Piston rod worn.	Replace piston rod.
The motor operates, but the paint pump doesn't.	1. The pressure setting is too low.	Increase the pressure.
	2. The displacement is seized by dried paint.	Service the pump.
The motor and displacement pump operates, but paint pressure is too low, or none.	1. The pressure setting is too low.	Increase the pressure.
	2. The tip or gun filter is clogged.	Remove the tip and/or filter and clean them.
	3. Tip is worn.	Replace tip.
	4. The fluid displacement pump filter (if used) is clogged.	Clean the filter.
	5. There is a large pressure drop in the fluid hose.	Use a larger diameter hose.
The displacement pump operates, but the output is too low on the down stroke or both strokes.	1. The lower check valve ball is not seating properly.	Service the lower check valve ball check.
The displacement operates, but the output is too low on the upstroke.	1. The upper check valve ball is not seating properly.	Service the upper check ball valve.
	2. The lower packings are worn or damaged.	Replace the packings.
The displacement pump operates but the pressure is too low.	1. Tip too large.	Use smaller tip.
	2. Long extension cord causes power drop.	Use less extension cord.
Motor stops.		Reset overload switch.
The displacement pump operates but the unit does not prime.	1. Upper or lower ball is stuck or obstructed.	Service upper and lower check ball valve.
	2. Unit hose air leak (bubbles blowing out bypass hose.)	Inspect suction hose for holes, if so equipped. Ensure suction nut is tight and lower ball cage O-ring is not worn.
Unit does not run.	1. Thermal breaker tripped.	Press re-set button
	2. Electrical failure	Contact local Airlessco Service Center.
Machine does not start.	1. Control Settings	Step 1. Ensure the ON-OFF toggle switch is in the "ON" position and that the Pressure Control Knob is fully CW (maximum pressure). Also check that the unit is plugged in. Step 2. Remove the electrical cover on the bottom of the machine. Check if the green power light on the board is lit. If the light is "OFF", proceed to Step 3. If the light is "ON", go to step 7.
	Power Source	Use a multi-meter to check
Unit will not prime.	1. Dried out piston packings and stuck ball valves.	Remove siphon tube and feel lower ball check to be sure it is free to move off its seat. Place full cup of paint thinner over end of fluid section and turn on pump.
	2. Pump inlet screen plugged or air in pump or hose.	Remove and clean.
		Hold gun trigger in open position and run unit about 10 seconds until air is purged.
		Check for siphon tube leak.
	3. Packings worn.	Replace.
	4. Fluid too viscous.	Prime pump with compatible solvent. Bring up to pressure, carefully remove pump from solvent container and immerse inlet tube into heavy material to be sprayed. With nozzle tip removed, trigger gun until heavy material appears aat gun. Replace nozzle tip and you're ready to spray.
	5. Siphon tube clogged.	Remove and clean.
	6. Siphon tube air leak.	Check connection and seal.
	7. Clogged tip.	Relieve pressure, remove tip and clean.
Unit will not build or maintain pressure.	1. Pressure adjusting knob not properly set.	Adjust to increase pressure.
	2. Pump inlet strainer dirty.	Clean or temporarily remove.
	3. Valve balls or seats worn or dirty.	Replace or clean.
	4.Air in pump or hose.	Hold gun trigger in open position and run about 10 seconds until air is purged.
		Check for siphon tube leak.
	5. Packings worn.	Replace.
	6. Worn spray tip.	Replace.
	7. Internal leakage.	With gun trigger closed, allow unit to pump up to pressure and shut off. If pump momentarily starts, internal leak is indicated and fluid section rebuild is necessary.
	8. Fluid leak.	Check for external leaks including hydraulic fittings attached to pressure control housing.
	9. Fluid too viscous.	Consult manufacturers recommendations on paint container label.
	10. Too large a spray tip.	Change tip.
Fluid leakage out relief hole at pressure control.	1. Worn "O" Rings.	Repack or replace transducer.
Fluid leakage at upper end or fluid section.	1. Upper packings.	Relieve pressure and tighten packing take up nut or replace packings.
	2. Piston rod worn	Replace.
Bad spray pattern.	1. Too large a tip size	Change to a smaller tip size
	2. Pressure adjustment wrong.	Adjust pressure control knob.
	3. Insufficient fluid delivery.	Clean all strainers and filters in system.
	4. Fluid too viscous.	Add solvent to fluid according to manufactures recommendations.
Unit lacks power.	Pressure adjustment low.	Increase.
	Improper voltage supply.	Reconnect input voltage for 115 VAC
Blown fuses at pump.	1. Excessive pressure.	Have service center recalibrate the pressure control.
	2. Excessive extension cord length or improper wire gauge.	Use #12 gauge wire or larger up to maximum of 200 feet. For additional length, more airless hose may be used.
Unit will not prime.	1. Dried out packings or stuck valve balls.	Remove siphon tube and feel lower ball check to be sure it is free to move off its seat. Place full cup of paint thinner over end of fluid section and turn on pump.
	2. Stuck valve balls.
	3. Pump inlet screen plugged.	Remove and clean.
	4. Air in pump or hose.	Hold gun trigger in open position and run unit about 10 seconds until air is purged.
		Check for siphon tube leak.
	5. Packings worn.	Replace.
	6. Fluid too viscous.	Prime pump with compatible solvent. Bring up to pressure, carefully remove pump from solvent container and immerse inlet tube into heavy to be sprayed. With nozzle tip removed, trigger gun until heavy material appears at gun. Replace nozzle tip and you're ready to spray.
	7. Siphon tube clogged.	Remove and clean.
	8. Siphon tube air leak.	Check connection and seal.
	9. Clogged tip.	Relieve pressure, remove tip and clean.
Unit will not build or maintain pressure.	1. Pressure adjusting knob not properly set.	Adjust to increase pressure.
	2. Pump inlet strainer dirty.	Clean or temporarily remove.
	3. Valve balls or seats worn or dirty.	Replace or clean.
	4. Air in pump or hose.	Hold gun trigger in open position and run until air is purged.
	5. Packings worn.	Replace.
	6. Worn spray tip.	Replace.
	7. Internal leakage.	With gun trigger closed, allow unit to pump up to pressure and shut off. If pump momentarily starts, internal leak is indicated and fluid section rebuild is necessary.
Paint will not shut off at spray tip of airless gun.	1. Seat in the gun dirty.	Trigger gun several times under pressure.
	2. Needle stop nut too tight.	Loosen the stop-nut.
	3. Worn valve assembly.	Replace valve assembly.
Airless pump motor doesn't turn over.	1. No power.	Check house electrical fuse (use at least a 15 amp).
	2. Thermal overload switch.
	3. Unit under pressure.	Turn bypass valve to prime.
	4. Defective switch or wiring.	Replace switch, check wiring; replace if necessary.
Gun will not spray.	1. Trigger safety on.	Disengage trigger stop.
	2. Inline filter clogged.	Clean or replace mesh filter.
	3. Adjustable tip clogged.	Turn knob counterclockwise.
Spray pattern has "tails" or fingering.	1. Pressure too low.	Increase pressure at pump.
	2. Material too thick.	Thin per manufacturer's recommendation.
	3. Tip adjusted too wide.	Reduce pattern size.
	4. Spray tip worn.	Install new tip.
Distorted pattern	1. Plugged or worn tip	Clean or replace tip.
Pump draws up paint but the pressure does not build up.	1. Bypass valve in "prime" position.	Turn valve to spray.
	2. Air in hydraulic system.	Bleed air from system.
	3. Pressure valve not adjusted or worn.
	4. Inlet valve worn.	Replace.
	5. Low oil level.	Check oil.
	6. Bypass valve clogged or worn.	Clean or replace.
Pump draws up paint, pressure builds but drops when the gun is triggered.	1. Material too thick.	Thin paint per manufacturer's recommendation.
	2. Bypass valve not shutting off.	Clean or replace.
	3. Air in the paint.	Check suction hose & connections.
	4. Air in hydraulics.	Bleed.
	5. Tip orifice too large or worn.	Adjust tip or replace strainer.
	6. Suction strainer clogged.	Clean and replace.
	7. Inlet or outlet valve worn.	Replace.
Spray tip keeps clogging.	1. Contamination in paint.	Strain paint. Clean or replace filters.
	2. Paint dried in the spray tip.	Keep tip moist when not spraying.
		Replace tip with adjustable tip.
Sprayer does not start up.	1. Sprayer not plugged in.	Plug in.
	2. On-Off switch Off.	Flip switch On.
	3. Blown fuse in circuit.	Replace fuse.
	4. Low voltage at wall plug.	Test power supply voltage.
	5. Bad On-Off switch.	Take to authorized service center.
	6. Damaged motor cord or extension cord, or voltage too low.
	7. Motor problem.	Take to authorized service center.
Sprayer starts up but does not draw in paint.	1. No paint or suction tube not totally immersed in paint.	Add more paint. Immerse suction tube in paint.
	2. Suction filter clogged.	Clean filter screen.
	3. Suction tube loose at inlet valve.	Clean connection and tighten.
	4. Inlet valve stuck.	Push valve with a pencil.
	5. Outlet valve is stuck, dirty or has worn out parts.	Push the push button valve on the block to loosen or remove outlet and replace.
	6. Bypass knob in "Spray" position.	Turn bypass knob to "Prime".
	7. Pressure knob in "Low" setting.	Turn pressure knob to "High".
	8. Air in the hydraulic system.	Bleed air out of the unit.
	9. Bypass Valve plugged.	Remove to clean or replace. Take to service center.
	10. Suction tube problem.	Check for air leaks. Replace if necessary.
	11. Inlet valve damage (neck).
No sound.	1. Not plugged in.	Check plug & extension cord. Check motor switch
	2. House circuit breaker.	Check breaker. Try another electrical outlet.
	3. Thermal overload switch tripped.	Feel motor case. If hot, turn "off". Let cool & check motor case before starting.
Hums, but does not start or run correctly.	1. Pump under pressure.	Turn bypass valve to prime.
	2. Incorrect voltage.	Check house voltage.
	3. Extension cord.	Maximum length 100' - 10 ga.
	4. Condenser.	Replace. See service center.
Will not prime, has vacuum.	1.Suction filter clogged.	Clean filter or replace.
	2. Air leak in suction set.	Check connections. Clean and tighten.
	3. Suction head not submerged.	Check. Add more paint.
	4. Paint too thick.	Thin as recommended.
No Vacuum.	1. Bypass knob on "spray".	Turn counterclockwise.
	2. Pressure knob on "low".	Turn pressure knob clockwise.
	3. Inlet valve stuck.	Remove suction hose. Press inlet valve with finger to free.
	4. Outlet valve stuck.	Pour small amount of liquid in inlet valve to prime. If necessary, remove outlet plug and free the outlet ball.
	5. Air in oil system.	Check oil level & bleed system.
	6. Inlet valve worn.	Check and replace per manual.
	7. Outlet valve worn.	Check and replace per manual.
	8. Oil in the paint?	Replace diaphragm per manual.
Primes, but no pressure.	1. Suction filter.	Clean filter or replace.
	2. Bypass valve on prime.	Turn knob clockwise to "spray".
	3. Bypass vale leaking.	Check for flow out o
	4.Air in oil system.	Check oil and bleed system.
Low pressure.	1. Gun filter clogged.	Clean or replace.
	2. Suction filter clogged.	Clean or replace.
	3. Paint too thick.	Thin as recommended.
	4. Outlet valve worn.	Check & replace.
	5. Pressure valve worn.	Reset pressure or replace.
Good pressure, but no spray.	1. Gun filter.	Clean or replace.
	2. Tip clogged.	Remove and clean.
Gun.
Drips paint with trigger released.	1. Dirt in gun valve.	Disassemble & clean.
	2. Worn gun valve.	Replace per gun manual.
Drips while spraying.	1. Spray tip worn.	Replace.
Sprays uneven.	1. Dried paint in spray tip.	Remove and clean.
	2. Spray tip worn.	Replace.
Electric shock while spraying.	1. Pump not grounded.	Check extension cord and house circuit.
	2. Metal object being painted not grounded.	Attach ground wire to object.
Material will not shut off at spray tip of Airless Gun.	1. Ball or seat in gun dirty.	Try triggering gun several times while under pressure.
	2. Diffuser seat worn.	Replace Diffuser assembly.
	3. Needle assembly worn.	Replace if necessary.
Airless gun will not spray.	1. No pressure at gun.	Check pump for proper operation, check filter and strainer (clogged).
	2. Spay tip clogged.	Clean tip with pointed needle and blow with compressed air.
Airless gun has tails in spray pattern.	1. Material pressure too low.	Increase pressure at unit.
	2. Material too thick.	Thin paint per manufacturer's recommendation.
	3. Spray tip worn.	Replace.
Airless pump motor doesn't turn over.	1. No power.	Check electrical fuse.
	2. Defective switch or wiring.	Replace switch, check wiring; replace if necessary.
	3. Unit under pressure.	Turn combination valve counterclockwise to positive stop.
	4. If the above problems cannot be corrected, the motor could be defective.	Replace motor if necessary.
Airless pump does not draw paint.	1. Suction tube not totally immersed in paint.	Add more paint.
	2. Suction tube loose and draws in air.	Tighten clamp and fittings at inlet valve.
	3. Suction tube damaged.	Replace if necessary.
	4. Suction strainer clogged.	Clean or replace.
	5. Air in hydraulic system due to fluid level low in crankcase or due to shipment.	Add 10W-30 oil to crankcase. Bleed air from system.
	6. Combination valve not open or clogged.	Turn valve counterclockwise to positive stop. (Clean if Clogged)
	7. Outlet valve stuck or worn.	Dismantle and clean valve. Replace worn valve and ball. Check other parts for wear.
	8. Inlet valve stuck or worn.	Dismantle and clean valve, replace if worn.
Airless pump draws up paint but pressure does not build up.	1. Combination valve in open position clogged or defective.	Close valve. Clean or replace.
	2. Air in hydraulic system.	Bleed air from system.
	3. Outlet valve defective.	Dismantle and replace valve and ball. Check other parts for wear. Replace if necessary.
	4. Defective suction tube.	Replace.
	5. Inlet valve defective.	Replace.
	6. Paint used has too high a content of silica such as the cement paint or block filler.	Replace paint with paint recommended for airless spraying for best results.
Airless pump draws up paint, pressure builds up but drops immediately when gun is opened.	1. Tip orifice too large or worn.	Select smaller tip or replace.
	2. Suction strainer clogged.	Clean or replace filters.
	3. Suction tube loose or inlet valve loose.	Tighten clamp and fittings at inlet valve.
Fluid pressure.	1. Check pressure knob setting. The pump won't develop much pressure if it is at minimum setting (fully clockwise).	Slowly increase pressure setting to see of motor starts.
	2. Check for a clogged spray tip or fluid filter, if used.	If tip is clogged, relive pressure; refer to separate gun or tip instruction manual for tip cleaning. Clean or replace element.
Mechanical.	1. Check for frozen or hardened paint in pump. Using a screwdriver, carefully try to rotate fan at back of motor bt hand.	Thaw. Plug in airless paint sprayer and turn it on. Slowly increase pressure setting to see if motor starts.
	2. Check pump connecting rod pin. It must be completely pushed into connecting rod and retaining spring must be firmly in connecting rod groove. Push pin into place and secure with spring retainer.	Push pin into place and secure with spring retainer.
	3. Check for motor damage. Remove drive housing assembly. Try to rotate motor fan by hand.	Replace motor if fan won't turn.
Electrical.	1. Check electrical supply with volt. Meter should read 105-125 VAC.	Reset building circuit breaker; replace building fuse. Try another outlet.
	2. Check extension cord for visible damage. Use a volt meter or test amp at extension cord outlet to check.	Replace extension cord.
	3. Check sprayer power supply cord (50) for visible damage such as broken insulation or wires.	Replace power supply cord.
	4. Check motor brushes for the following:
	a. Loose terminal screws.	Tighten.
	b. Broken or misaligned brush springs.	Replace broken spring and/or align spring with brush.
	c. Brushes binding in holders.	Clean brush holders. Remove carbon with small cleaning brush. Align brush leads with slot in brush holder to assure free vertical brush movement.
	d. Broken leads.	Replace brushes.
	e. Worn brushes.	Replace brushes if less than 0.5 inches long.
	5. Check motor armature commutator for burn spots, gouges and extreme roughness. Remove motor cover and brush inspection plates to check.	Remove motor and have motor shop resurface commutator if possible.
	6. Check motor armature for shorts using armature tester (growler) or perform motor test.	Replace motor.
	7. Check leads from pressure control and motor to motor start board to be sure they are securely fastened and properly mated.	Replace loose terminals; crimp to leads. Be sure male terminal blades are straight and firmly connected to mating part.
	8. Check motor start board by substituting with a good board.	Replace board.
	9. Check power supply cord. Disconnect black and white power cord terminals; connect volt meter to these leads. Plug in the sprayer. Meter should read 105-125 VAC. Turn off and unplug sprayer.	Replace ON/OFF switch.
	10. Check ON/OFF switch. Disconnect the motor start board and switch and connect volt meter between exposed terminal on switch and power cord's white wire. Plug in sprayer and turn ON. Meter should read 105-125 VAC. Turn off and unplug the airless paint sprayer.	Replace ON/OFF switch.
	11. Check motor thermal cutout switch. Connect ohmmeter between motor's red leads. Meter should read 1 ohm maximum.	Allow motor to cool. Correct cause of overheating. If switch remains open after motor cools, replace motor.
	12. Remove pressure control and check micro switch operation with ohmmeter. 1. With pressure knob at lowest setting and stem pushed into control, readings should be: white & black = 1 ohm max. White and red = open. 2. With pressure knob at highest setting, reading should be: white and black = open; white and red = 1 ohm max.	Replace pressure control.
	13. Check pressure transducer for hardened paint or damaged or worn components.	Replace transducer. Thorough system flushing will help extend the life of transducer.
Low output.	1. Check for worn spray tip.	Follow pressure relief procedure then replace tip. See your separate gun or tip manual.
	2. Be sure pump does not continue to stroke when gun trigger is released. Plug in and turn on sprayer. Prime with paint. Trigger gun momentarily, then release and lock safety latch. Relieve pressure, turn off and unplug the airless sprayer.	Service pump.
	3. Release gun trigger. Observe resting position of pump rod.	If pump consistently comes to rest with rod fully extended, the piston packings and/or piston valve may be worn. Service the pump.
	4. Check electrical supply with volt meter. Meter should read 105-125VAC.	Reset building circuit breaker; replace building fuse. Repair electrical outlet or try another outlet.
	5. Check extension cord size and length; must be at least 12 gauge wire and less than 150ft long.	Replace with a correct, grounded extension cord.
	6. Check motor brushes. See Electrical - What To Check, item 4, on page 13.
	7. Check motor start board by substituting with a good board.	Replace board.
	8. Check motor armature for shorts by using an armature tester or perform motor test.	Replace motor.
Drain Valve leaks.	1. Check drain valve for correct torque and/or worn parts. Check for debris trapped on seat.	Tighten to 185 in-lb. Clean valve and replace with a new gasket and sealant.
Transducer leaks.	1. Slight leakage from transducer is normal.	Periodically remove residue from its cylinder port.
No output: motor runs and pump strokes.	1. Check paint supply.	Refill and reprime pump.
	2. Check for clogged intake strainer.	Remove and clean, then reinstall.
	3. Check for loose suction tube or fittings.	3. Tighten; use thread sealant on NPT threads of adapter.
	4. Check to see if intake valve ball and piston ball are seating properly.	Remove intake valve and clean. Check ball and seat for nicks; replace as needed. Strain paint before using to remove particles that could clog pump.
	5. Check for leaking around throat packing nut which may indicate worn or damaged packings.	Replace packings. Also check piston valve seat for hardened paint or nicks and replace if necessary. Tighten packing nut/wet-cup.
	6. Release gun trigger. Observe resetting position of pump rod.	If pump consistently comes to rest with rod fully extended, the piston packings and/or piston valve may be worn. Service the pump.
No output: motor runs but pump does not stroke.	1. Check displacement pump connecting rod pin.	Replace pin if missing. Be sure retainer spring is fully in grove all around connecting rod.
	2. Check connecting rod assembly for damage.	Replace connecting rod assembly.
	3. Be sure crank in drive housing rotates; plug in sprayer and turn in briefly to check. Turn off and unplug sprayer.	Check drive housing assembly for damage and replace if necessary.
Pattern Surging	1. Pulsating fluid delivery.	Change to smaller tip.
	3. Leak in siphon tube.	Check siphon hose and others in system.
	4. Too many guns for pump.	Reduce number of guns.
Spray pattern variations.	1. Spray tip worn beyond sprayer pressure capability.	Replace spray tip.
	2. Check transducer for wear or damage.	Replace transducer.
	3. Check pressure control for smooth operation.	Replace pressure control.
	4. Check low output section.
Motor is hot and Runs Intermittently.	1. Determine if sprayer at high pressure with small tips, which causes excessive heat build up.	Decrease pressure setting or increase tip size.
	2. Be sure ambient temperature where the airless paint sprayer is located is no more than 90 degrees F and sprayer is not located in direct sun.	Move sprayer to shaded, cooler area if possible.
	3. Check motor.	Replace motor.
Building circuit breaker opens as soon as sprayer switch is turned on.	1. Check all electrical wiring for damaged insulation, and all terminals for loose fit or damage. Also check wires between pressure control and motor.	Repair or replace any damaged wiring or terminals. Securely reconnect all wires.
	2. Check for missing motor brush inspection plate gasket, bent terminal forks or other metal to metal contact points which could cause a short.	Correct faulty connections
	3. Check motor armature for shorts. Use an armature tester or perform motor test. Inspect windings for burns.	Replace motor.
	4. Check motor start board by substituting with a good board.	Replace board.
Building circuit breaker opens as soon as sprayer is plugged into outlet and sprayer is NOT turned on.	1. Check ON/OFF switch. Be sure sprayer is unplugged! Disconnect wires from switch. Check switch with ohmmeter. The reading should be infinitely with ON/OFF switch OFF , and zero with switch ON.	Replace ON/OFF switch.
	2. Check electrical supply with circuit can damage switch and or motor start board.	If voltage is too high, do not operate sprayer until corrected.
Unit will not run on generator but does run on AC power.	1. Check the generator's peak voltage. This airless paint sprayer will not run if the peak voltage is above 190V.	Use AC power or a different generator.
No pressure.	1. Be sure the pump is primed.
	2. Be sure the gasket 667-30 is in place and that the fitting is tight.
	3. Dirt and foreign particles are common causes. Remove pump intake head. Clean and inspect check valve and cage for clearance. More than 1/16" may prevent the ball from sealing quickly. If clearance is less than 1/32", ball may not open sufficiently and pump will starve. Paint should be strained in a separate container.
Insufficient pressure or no pressure - No obvious symptom.	1. Paint strainer bag sucked around the bottom of the siphon assembly. If it is, the bag may not allow enough material into the pump and the pump will starve. Paint should be strained in a separate container.
Insufficient pressure - Paint line vibrates when not spraying.	1. Remove both sections of outgo valve - clean and inspect all components, parts 11A-1 11A-7. Ball should be round, free of nicks and cuts and not smaller than .360 diameter. Check legs and roof of cage for wear and ball with cage on the seat. Check spring for excessive wear - it must be long enough to be in compression when seat is all the way in its nest. Replace any or all o these parts as necessary.
No Pressure, No obvious symptom.	1. Air/Vapor in hydraulic side of pump.	A. Release pressure, if any, at gun and leave gun closed.
		B. Be sure there is fluid in the paint tank. If oil is not pumping freely back to hydraulic reservoir tank, remove knob from pressure control valve and pull stem back gently 1/8" with fingers to free ball on seat and allow oil to pump out with no resistance for several minutes. Replace knob on pressure control valve. Screw on until desired pressure is obtained.
No pressure - No obvious symptom.	1. Pressure control valve - when working properly, this valve will not bypass oil below the pressure for which it is set. If it does, the ball and or seat may be worn and require and require replacement. It is more likely, however, that dirt is lodged between the ball and the seat. Dismantle and clean thoroughly.
Insufficient or no pressure - No obvious symptom.	1. Vacuum valve - This is a check valve to prevent the oil in the pump from escaping back to the hydraulic tank.
	2. Vacuum valve - It also regulates the flow of oil into the pump. If it is not checking, there will be a loss of pressure. If it is not admitting oil freely, there will also be a loss in pressure. In either case, this valve should be replaced.
Insufficient or no pressure.	1. If the four principle valves in the preceding steps have been covered and thoroughly checked, there are only two other possibilities. One is for excessive oil leakage at the end of pressure cylinder. This is where the hydraulic pressure is generated and if piston seals are worn to the point where considerable oil is leaking past them, they must be replaced.
	1.(continued) The other location is the diaphragm. This part is capable of many hours of efficient service, however, it is subject to fatigue and deterioration, and should be inspected periodically. Pressure blisters, regular or irregular pattern are normal, however, if diaphragm is encrusted with dried paint or is hard and stiff from use and exposure to paint chemicals, it should be replaced with repair kit. Replacement every year of use is recommended.
Insufficient or no pressure.	1. Flow control valve could be defective. Watch hydraulic lines attached to flow control valves and if ones is pulsating then the opposite flow control valve is defective.
Engine stalls out.	1. Drive belt slippage - belts are designed for use under high tension. Belts can be tightened by adjusting the belt tightener.

Graco Airless Paint Sprayers

Airless Paint Sprayer Trouble Shooting Guide

Problem

Cause

Solution