My 640 titan run but will not prime it does not spray product

I am not very familiar with airless sprayers but try this link to a youtube video...

https://www.youtube.com/watch?v=5DGUHwBmdaM

It could be a short in the unit from getting wet, pump may be getting seized by dried paint in pump or your using too small of a extention cord

Wouln't pick up piant improper cleaning

Your prime system needs to be cleaned . Read on how to correctly clean mechine after each use

You don't clean it right what do you expect

The Lower ball is probably stuck on a piece of paint on the lower ball seat.
Solution: (requires looking at your owners manual)
Smack the area where the lower ball and seat are with a hammer while running and rinsing with water.
If this does not work you will have to pull the lower ball and seat.
Did you clean pump with water, if you did did you run paint thinner thru pump? This will prevent parts from rusting or corroding.

If you still have a problem with a Titan 640i please give us a call. We introduced this sprayer to the UK back in 1985. Lion Industries UK Ltd 01543 251 560

When you switch it from prime to paint and it's still running:
- If paint/water continues to come out of the prime tube, your prime valve isn't seating properly and needs to be replaced.
- If you get a little pressure at the paint gun but it is surging, your packings, most likely the lower set, are damaged and letting most of the paint leak back past them. Packing/seal kits are available for your machine. Use all parts in the kit and grease/lubricate all of the parts well. Inspect the piston and cylinder for scoring or pitting that can damage new seals. They should be mirror smooth for proper operation and life of the seals.

i can help if i know the manufacture or had a picture.
quite possibly the lower / inlet ball valve is sticking or has someting stoping it from seating properly. so your fluid is going in and out the inlet.