Check the free things first. If the 640 will not prime, turn PRIME/SPRAY to PRIME, free a stuck inlet valve with the pusher stem, then look for an air leak or a clogged inlet screen or filter. If it will not hold pressure, check for leaks, clogs and a worn tip before blaming the packings or valve balls. Pulsing at the gun points to worn upper packings.
Before you start
Everything below follows Titan's Impact 640 manual, and where noted its Impact 1040 manual, which agrees on the same points. Your own manual is the authority for your sprayer. Several of the steps involve opening the system, so relieve pressure first. The Impact 640 manual describes locking the gun, turning the sprayer off, turning the pressure knob to OFF, triggering the gun into a grounded metal container and setting PRIME/SPRAY to PRIME.
The unit will not run
If the motor does not start, Titan's manual lists these causes: the sprayer is not plugged in, the breaker has tripped, the pressure knob is at minimum, a wire is loose, the motor is too hot, or the ON/OFF switch is defective. Do the first three and the motor-too-hot check yourself. Loose wiring is a service center job, per the manual.
The controls and electrical parts are on the Main Assembly page: the 9850936 Power Switch, the 805-354 Control Knob and the 800-929 15A fuse. If the Digi-Trac display shows an error, the sprayer shuts down. Titan's manual excerpts name High Control Temperature and Check Motor as examples, and say to take the unit to a Titan service center. We do not list other codes.
The unit will not prime
The motor runs but no paint comes out. Titan's manual lists these causes, and they are in rough order of how quick they are to check:
PRIME/SPRAY in SPRAY
Turn it to PRIME. This is the simplest cause and it happens often.
Inlet valve stuck
The manual says to insert the pusher stem. Titan lists a Sureflo Pusher Valve on the 640 for releasing a stuck inlet ball without tools. The pusher assembly on the 640 Fluid Section page is 805-216A.
Air leak at the siphon tube or suction set
Tighten the connection or re-tape it with PTFE tape, as the manual says.
Clogged pump filter or inlet screen
Clean them. The inlet screen filter is 700-805 on the Suction Set page.
Clogged siphon tube or suction set
Remove and clean it.
If none of those fixes it, the inlet valve may be worn. The 805-846 Inlet Valve Kit is listed for the 640 and several other Impact models; ask us to confirm the contents before you order.
It will not build or hold pressure
The sprayer runs and primes, but pressure stays low or drops. The manual's list, for the 640 and the 1040 alike:
- An air leak: check the siphon connection as above.
- A clogged filter or inlet screen: the manifold filter is 730-067, a 60 mesh element.
- A worn tip: the tip seat and seal kit on the Accessories page is 661-020. A worn tip has a wider orifice, so pressure falls and the pattern turns coarse.
- An internal leak in the fluid section: worn or dirty packings, or worn valve balls. The manual says to clean the valves and service the fluid section.
Work down the list. Filters and the tip are quick and inexpensive to check, and rule out most of the common causes before you touch the pump. If you get to the fluid section, the parts are on the Fluid Section page: the 805-845 Outlet Valve Kit for valves and the 704-564 Upper Packing Kit for packings. We do not describe the repacking steps here, since the manual covers them.
Pulsing and leaking at the top
Titan's manuals tie pulsing or surge at the gun to worn upper packings, and the fix is to repack. A leak at the top of the fluid section has a short list: an external leak where a fitting needs tightening, worn packings or balls, or worn valve seats. The manual says worn seats can be reversed or replaced. That is Titan's wording from one manual; follow the manual's procedure for your sprayer. For the part-by-part pump end walk-through, see our post on the Impact 640 packings, piston and valves.
Poor spray pattern
A coarse, streaky or uneven pattern has three causes in Titan's manual: a worn tip, a tip that is too large for the job, or a clogged pump filter, gun filter or inlet screen. Replace the tip or use a smaller orifice, as the manual advises, then clear the filters. Our general advice agrees with the manual: a tip wears gradually and the pattern degrades long before the sprayer fails, so a new tip is the first thing to try.
Parts for the checks above, with live prices:
−10%
The order to work in
Valve position, then suction side, then filters, then tip, and only then the fluid section. Most of the causes on Titan's list are free or inexpensive to rule out. If you have been through the list and the 640 still will not behave, call (713) 931-0006 with your serial number.
Still stuck after the checklist?
Call (713) 931-0006 with your model and serial number and our parts team will help you work out which part to order.
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