Looking online, the k1 is cheaper than the k7, any substantive reason to choose the K7? I am having a hard time determining the differences between the k7.1,.2,.3, but read about issues with one of the k7 unloaders.
Any advice would be appreciated. Think my unloader is going, have a backup but need a backup for that one once replaced.
Get the K7 if you like having to fiddle with unloaders during jobs. Otherwise the K1 is fine.
Thank you sir. I don’t like messing with anything, at all. I just want to put chems in my tank, fire up the rig, and start spraying and praying. The k1 is about 1/2 price vs the k7 at the PW store I normally order from.
Get the K1 be done with it. Mine has been darn near perfect since I put it in early last year. It did have a slight ‘cavitation’ feel last month but a little tweak on the adjuster bolt cleared it up.
Thanks. Appreciate the feedback.
I don’t see your gpm but I will say the ZK1 wouldn’t work with my 4 gpm rig last year when I tried it. At 6.8 it has enhanced my quality of life around the clock to say the least.
Thank you for taking the time to respond. Guess the zk1 will get ordered this weekend.
If you don’t have an extra one on hand get one ordered ASAP. That’s a tell tell sign it’s on it’s way out
No kidding! I’ve got 500ish hours on mine & today it decided it didn’t want to do any surface cleaning. Just pulsed on and off, same with a pressure nozzle. Worked great until then. Going to get a fresh one on the way & attempt to see if I can get this thing apart to have a gander. The Pulsar got me through the job but the Dirty Harry recoil has got to GO.
Keep worn spray nozzles on hand to squeeze more life out of it.
Have you had one of these things apart? I’m a bit curious if it has a wear component where the failure occurs but have zero clue of the mystical inner workings. I just thought it was magic or something until today.
The orifice enlarges. I use a .1 size (ZK5.1) even though I was flowing 4.75 gpm. And the spring gets weak.
You know your stuff dude! Sharp as a tack.
My knowledge base is only a reflection of my years here on earth 
Sadly I started my journey late in life conquering CAD, CAM and CNC. Mechatronics will be where it ends. I’m turning 47 the 20th and I’m nowhere near where I want to be! Spent way too long behind a gun I suppose.
