Unloader killer

[One Tough Pressure 580]

So lets hear some valid reasons why I would break 2 unloaders in a one week period.

Both were ZK1 flow unloaders, both had broken springs, and both were on the same machine.

Pump is rated 8 at 3600, but running 8 at 3000. Coil has minimal back pressure, and machine is tank fed and bypasses back to the tank.

What gives?

[John Orr 206]

Is there an 8gpm virus going around? :) ...but I would like to know the answer too.

[Tmrrptr 164]

So lets hear some valid reasons why I would break 2 unloaders in a one week period.

Both were ZK1 flow unloaders, both had broken springs, and both were on the same machine.

Pump is rated 8 at 3600, but running 8 at 3000. Coil has minimal back pressure, and machine is tank fed and bypasses back to the tank.

What gives?

Since the first one of the week that broke was most likely not from the same production run as the second one installed, and subsequently broke, its probably not a bad run of springs.

Something in the system is over-exercising the unloader.

air sucked into pump intake causing cavitation and pulse in output?

bad valve in pump creating a pulse?

Is there a pulse?

Hot in the valley causing frequent work stoppages to look at young females dressed for the SoCal weather ?

What tool was being used? Wand, or ?

Did you notice erratic pressure before failure?

It could just be the odds...

1. watch out for lightning, stay off golf courses.

or

2. Buy Lottery tickets quickly.

r

[One Tough Pressure 580]

Since the first one of the week that broke was most likely not from the same production run as the second one installed, and subsequently broke, its probably not a bad run of springs.

Never know there, since it does not seem like many folks run the ZK1's, so maybe they did come from the same batch. I shall contact General Pump and start asking questions.

Something in the system is over-exercising the unloader.

air sucked into pump intake causing cavitation and pulse in output?

bad valve in pump creating a pulse?

Is there a pulse?

Yes, I have a pulse, I am not dead yet, oh wait you mean the machine. A slight one, nothing major, but I did have to replace the packings.

Hot in the valley causing frequent work stoppages to look at young females dressed for the SoCal weather ?

I only work at night, so the females I see are neither young or worth looking at. They usaully have on everything they own in several layers to prevent theft.

What tool was being used? Wand, or ?

Did you notice erratic pressure before failure?

First clue was the surfacer would make the machine cycle, yet the wand worked fine. I went thru everything on the surfacer thinking there was a blockage in it, but then the wand started to do it too. Had to bypass the unloader and run an open gun to finish the job. Come to find after the fact that I was running low on pressure due to the packings, so when the unloader broke, it was not even really being worked very hard.

Now that the packings are fixed and new unloader is on, lets see how long it lasts.

[John Orr 206]

Hmmm...the symptoms sound familiar. Glad I recently asked my local shop to order me a rebuild kit. (I also run the Z1 and have noticed a pulse and the occasional cycling.) I guess I can't complain, since my two year old rig (3000psi/8gpm HydroTek) has about 2000 hours on it.

[One Tough Pressure 580]

John,

What are you paying for the rebuild kit? I was told they are the same as a new unloader. I pay around $105.00 with shipping.

[Tmrrptr 164]

In the Valley, the HOT ones come out at nite!

But I must have been in a different part of the Valley and I sure wasn't working!

Hmmmm. Maybe they were?

ok, how about this... somewhere in the pressure line, probably at a fitting connection, or someplace that was stressed real bad, part of the inner liner of the hose is damaged and making like a flap, restricting flow?

And it could be intermittent... yet it will get worse and maybe some will break loose and plug a... well, jet...

Is it chunks of that packing?

r

[John Orr 206]

John,

What are you paying for the rebuild kit? I was told they are the same as a new unloader. I pay around $105.00 with shipping.

Frankly, I didn't ask the price. lol I'll let you know when I schedule the rebuild.

[Hotwaterwizard 33]

I would like to know more about your plumbing from the tank to the machine. I had a simmular problem from one of my customers. He had 3/4 garden hose for the suction and I changed it to 1 inch Spyralflex Suction hose and the problem went away. You may also need a pulsation dampener in the line.

Inside of the Flow Unloader

http://www.generalpump.com/PDFs/Unloaders.pdf

Pump Installation Guide

http://www.generalpump.com/PDFs/ServiceManual.pdf

[One Tough Pressure 580]

3/4" mpt to 1" barb from the tank and then between 6-10 feet of hose depending on which tank. 1" hose goes to within 12 inches of pump and runs thru full port 3/4" ball valves to choose tank. Filter is also 3/4" and right at pump head attached with full port fitting. Filter is always clean.

Symptoms reappeared on last night, first the pulsation and then the cycling. I pulled the nozzle to check for clogs and pulled the trigger which burped a rust puddle. Nozzle back in and then psi/flow dropped, with no bypass to the tank, so I assume the packing are dead again.

Next thing was whammo, nothing! Walked around to see what the deal was and the Honda blew a hole in the side. Luckily the shrapnel did not hit my truck, or I would be even more pissed than I already am.

New engine will be here tomorrow, special thanks to Mark at Easy Clean Systems for expediting all my needed items. With no engine to test anything, I ordered another unloader and new packing so i am ready for whatever my fate calls for.

The coil must have a problem, despite no leaks and no major psi differentials, as that rust came from somewhere. The only other place that could produce rust in my system is the hose reel inner plumbing.

After the new packings and unloader last Thursday, I did pressure checks and all was normal.

I do run a pulsation dampner too. Factory All American.

[Hotwaterwizard 33]

Go to Delta rubber or Capitol Rubber and get the clear spiral hose that won't colapse. Another name for it is suction hose. Any rubber company should have it. With 8gpm I would use 1 inch hose and a filter.

Mark is also a Honda dealer so you may want to get a price from him.

I prefer the Green spring unloader. it has fewer issues than ZK1.

[One Tough Pressure 580]

My current hose is that clear braided hose similar to what comes with the X Jet, just in 1".

I have the barbs that go from 3/4" mpt to 1.5" barb and will put those on very soon.

[John Orr 206]

Though I fear my pump is going, based on what Alan has been going through, I swapped-out my ZK1 for the green spring unloader that came with my rig. Problem still there. Next, I plan on bypassing the coil in order to rule it out.

When the vibration/cycling started, I noticed a slight leak (only when not running) at the drain and I could see air bubbles in the supply hose. I tightened all connections and don't see any bubbles, but there is still a vey slight drip. Still waiting for the rebuild kit.

[Kory 14]

I was having a sim problem My seal on the water filter was going bad. Sometimes its simple stupid other times it costs a lot of money!

[David O'Connell Jr. 14]

One of our pumps pulsed before, then we double fed it. Now all our pumps are fed with 2 water lines.

[One Tough Pressure 580]

One of our pumps pulsed before, then we double fed it. Now all our pumps are fed with 2 water lines.

Do you mean from both sides of the pump head? Is this a tank fed or pressure feed? My pulley setup will not allow a double feed without some extensive mods.

[John Orr 206]

Well, the pump rebuild was done yesterday and everything is better. (One of the seals had a chunk missing.) $75 for the part and $60 for the labor.

After the rebuild, I checked the pressure/flow with the Green Spring unloader and it was 3000 psi and just over 8 gpm. I reinstalled the K1 unloader and could not get more than 2000 psi. Coincidentally, I had just washed the house of a fellow pressure washer and he had 2 K1's that he had tried and removed from one of his dual skid rigs, so we traded. New K1 installed and all is right with the world!

[One Tough Pressure 580]

Glad to hear something is going right. I replaced the packing, valves and all o-rings/fiber backing discs in my AR pump and it would not give out more than 1500 psi. This is a pump head pressure check, so no unloader, or coil to slow things down.

With no other choice, I went back to my General TS1021, and everything was fine. With the new 24 hp and that 1021, things are real sweet. The only thing I notice is that my water tank lasts much longer.