Unloader problem

[gregative]

Have an unloader problem. With the trigger open the machine is working good. When you let off and it goes to bypass it seems the machine is bogging down/having a hard time pushing the water. There is still some water flowing through the bypass but maybe not as much as it should. Casually observing I cannot see the hood on the unloader kicking up/down. Does this sound like an unloader problem? I'm thinking it is able to get enough through the bypass to keep the hose or something from busting yet not quite working. Do you think it's time to replace or can debris keep the unloader from opening/bypassing all the way? The unit is practically brand new. Suggestions please!

[Hummerbk]

That sounds like an unloader problem. Do you keep a spare around you can switch it out with?

Dave

[Paul Kassander]

if you have a leak or weeping gun it may also cause this problem as it is forcing some through the gun and some through bypass. Also if the unloader is adjusted to too high of a pressure this will exaggerate the problem. Make sure it is set to unload no higher than your operating pressure IE. 3000 psi.

[Mike Williamson]

Originally Posted by gregative

Have an unloader problem. With the trigger open the machine is working good. When you let off and it goes to bypass it seems the machine is bogging down/having a hard time pushing the water. There is still some water flowing through the bypass but maybe not as much as it should. Casually observing I cannot see the hood on the unloader kicking up/down. Does this sound like an unloader problem? I'm thinking it is able to get enough through the bypass to keep the hose or something from busting yet not quite working. Do you think it's time to replace or can debris keep the unloader from opening/bypassing all the way? The unit is practically brand new. Suggestions please!

What kind of unloader?

[Russ Johnson]

Take the outlet fitting off and check to see that the piston inside moves freely, and that the o ring is intact. Either will cause your unloader to act as a regulator.

[gregative]

The outlet piston was stuck. After freeing it the bogging of the engine seemed to be resolved. I also took Paul's advice and fixed a couple leaks down the line. The problem now is that there are no leaks but the unloader is cycling every couple seconds. Any thoughts on this matter?

[Mike Williamson]

Originally Posted by gregative

The outlet piston was stuck. After freeing it the bogging of the engine seemed to be resolved. I also took Paul's advice and fixed a couple leaks down the line. The problem now is that there are no leaks but the unloader is cycling every couple seconds. Any thoughts on this matter?

Again, what type of unloader?

[Russ Johnson]

Originally Posted by gregative

The outlet piston was stuck. After freeing it the bogging of the engine seemed to be resolved. I also took Paul's advice and fixed a couple leaks down the line. The problem now is that there are no leaks but the unloader is cycling every couple seconds. Any thoughts on this matter?

If you've made sure ALL downstream leaks are fixed, then check this...


Back the knob off enough to move the spring up a bit. Put a wrench on the flats below the spring and take it out. Ther should be o rings on the piston at the end of the stem. If there aren't or if they're torn, a couple of quick coupler o rings will fit. Can't recall ATM whether the 1/4 or 3/8 fit, but one of them does. Grease it up and put it back in.

[PWkid]

Mike, I am going to assume its a Flow type unloader, like a K-7.

[Mike Williamson]

Originally Posted by PWkid

Mike, I am going to assume its a Flow type unloader, like a K-7.

If that's the case, he may need to replace the orifice inside the bypass outlet, or replace it with one size smaller...I've had that happen twice, where the hole gets worn slightly larger. The first time, I actually fixed it by cutting the end off a nylon hosebarb and sticking that in behind the bypass outlet fitting. Restricted the flow enough to stop the constant cycling. I didn't have a replacement orifice, and I needed to work! Try crimping the bypass hose with a pair of pliars a little, maybe 1/2 way. If the cycling stops, that's your problem.

[Russ Johnson]

No, it's trapped pressure...it's got an outlet piston...

[PWkid]

Russ, thats why you make the big bucks.

[Mike Williamson]

Originally Posted by PWkid

Russ, thats why you make the big bucks.

That's right! He already knew without having to ask!

[gregative]

Sorry so late responding, computer went down. The unloader is the al-607 that came with a 2600psi/5.6g cold machine from espec. Since I freed the outlet piston, it worked for a week before it stuck again and I replaced it. Everything working good except now I'm about 1000psi short. No debris in the line & everything else seems ok. What do u think? By the way, the construction on this cold water unit beats my local distributors hands down.