Boy am I glad you posted this information. I've had a Devilbiss sprayer for a lot of years. I had to replace the pump once, but other than that, it has always worked well.
I have, however, cursed it from the day I bought it because it wouldn't suck the soap out of the bottle. I never thought about the fact that I needed to use the low pressure setting on the nozzle to get the soap to feed.
I'll have to try that the next time I use it.
Tom in TN