Graco 390 Airless Sprayer Problem (1 Viewer)

[Trevor]

I bought a Graco 390 because every inch of my house needs to be painted, inside and outside.

Last week, I sprayed the dining room with latex. It was the first time I used the sprayer. I flushed/cleaned it for about an hour after using it. This week, it doesn't work. When I turn it on, and turn the pressure roughly 1/4 up (per the instructions) the pump just runs continuously, and it won't build pressure. Nothing comes out of the prime tube. The filter is clean.

I bought this thing expecting to have to service it. However, I don't know where to start. I'm hesitant to just start unscrewing pieces from it. Any suggestions?

 

[Pin_Head]

I am not familiar with that model, but generally you need to disassemble the pump head and clean the inlet check valve and/or outlet check valve if there is one. Just running water through it won't really clean it completely.

Here is the manual with trouble shooting guide:
http://wwwd.graco.com/Distributors/DLibrary.nsf/Files/311737/$file/311737e.pdf

 

[turd]

i was thinkin grawdue on one of the balls as well,,,
probably the larger intake as it wont prime,,
if it is the small ball it is the high pressure side and it will prime up and then
cycle as it looses pressure past the small ball...
probably should dissassemble and clean it up,,,

flush with h20..drain,,,flush with mineral spirits and leave some in the pump...
rig up a gallon container with a hook/hasp to attach to the pump,,,sort of,,for storage
keep the pump lower in this container filled with mineral spirits,,,

burma shave

 

[Trevor]

Thanks for the info. I talked to a painter yesterday, and he said the same. He recommended hammering (lightly, of course) on the pump to try to loosen the ball, before attempting to disassemble.

I didn't have time to look at it yesterday.

 

[beaufort-fj60]

on my sprayer, you have to tape on the ball to loosen it.....

 

[copasspupil]

If it is like my Titan, it is easier than you think. They should have a rebuild kit and took me about 35 minutes to completely rebuild this titan I bought.

 

[harmonpa]

I ended up following these steps but still had to get a repair kit for mine to replace all the packings and ball and seats