k7 unloader problem

[jnoden 15]

the unloader is only a couple months old and it is already malfunctioning. When the gun is open it seems ok maybe a small loss of power. the problem is when I let off the trigger gun (closed gun) it pulsates real bad and the hp hose jumps all over the place from repeated build and loss of pressure.If I pinch off the bypass line to my tank it stops. Took it apart and didnt notice any problems. Replaced it with a cheap unloader and that one works fine so I know it is the unloader malfunctioning. Any Ideas?

[PWkid 79]

You need a smaller bypass oriface,I have a k-7 3 I run a size 1 oriface on my bypass to my tank.

[jnoden 15]

I would try that if it has been malfunctioning from the beginning but it ran fine for the first couple months. I just ordered a zk1. I heard the k7 has regular problems.

[PA Dutchman 14]

Jim,

My k7s have worked fine and then......similar issue like yours, the smaller orafice to the bypass has always cured the problem. Perhaps with our hard water here in PA, it effects the guts of the unloaders.

[PWkid 79]

I have a k-7 that I have used for three years and another one for a year and half no problems with either one. They might break down tommorow since I said that, but they are very reliable.

[Beth n Rod 1,279]

You need to change the orifice size in the inlet. If it is not the right size (use the old one) it will cause cycling.

Rod!~

[homer 64]

You need to change the orifice size in the inlet. If it is not the right size (use the old one) it will cause cycling.

Rod!~

There in not an orifice in the INLET - the orifice is in the outlet and that DOES NOT need to be changed.

The first reply was correct. The by-pass needs more restriction. This can be done by simply putting a 1/4" hose barb on the by-pass side of the unloader and reducing the by-pass hose down to 1/4" as well. You can use 1/4" poly braid chem line for the hose. The K-7 unloaders we catalog all have the 'stepped down' by-pass port installed so any size by-pass hose will work.

For example; a K7-3 will have a K7.2 by-pass port and a K7.2 will have the K7.1 by-pass port. Where evey you purchase your K7's from request the smaller by-pass port. You will only have to drop one size for them to work properly.

[Hotwaterwizard 33]

Just listen to all of the people telling you the Orifice needs to be smaller. They are right. I t will also malfunction if the Spray tip is too small. It is a flow actuated unloader. If you do not have a smaller Orifice use a 1/4 hose barb and a 1/4 hose on the bypass instead of 3/8 or 1/2

[MMI Enterprises 289]

Holy freaken cow!.. it's the master Hotwaterwizzard himself gracing our friendly forum..Hi John!!

Thought maybe you were out of the business or something since not seeing you online much...

When John speaks I listen...

..yea all should also.. :lgbow:

[Hotwaterwizard 33]

Well you got me laughing so bad I had to run to the restroom.

Come see me in Sacramento. I work there now. Precision Cleaning Systems on Alpine.

Nothing Cleans Like a Hotsy.

[MMI Enterprises 289]

Oh shut the heck up!!..lol , I didn't know you work there..wouldn't even recognize you. I was just there last week to get a new little ball for my downstreamer and was chattin with boss man about this and that. My little five year old was running all around and think you interrupted for a second while heading out to do errand... :)

[Hotwaterwizard 33]

LOL Neither one of us has a picture posted. How would we possibly know.

[Hotwaterwizard 33]

Here is a machine I rebuilt.

[Beth n Rod 1,279]

There in not an orifice in the INLET - the orifice is in the outlet and that DOES NOT need to be changed.

The first reply was correct. The by-pass needs more restriction. This can be done by simply putting a 1/4" hose barb on the by-pass side of the unloader and reducing the by-pass hose down to 1/4" as well. You can use 1/4" poly braid chem line for the hose. The K-7 unloaders we catalog all have the 'stepped down' by-pass port installed so any size by-pass hose will work.

For example; a K7-3 will have a K7.2 by-pass port and a K7.2 will have the K7.1 by-pass port. Where evey you purchase your K7's from request the smaller by-pass port. You will only have to drop one size for them to work properly.

Thank you for the correction in terms. Could not remember what it was called exactly but had the same problem with mine in the past. There is a type of bushing inside the by-pass port on the k-7 unloader that proportions the flow to the unit and the orifice (as it was explained to me by the repairing tech) has to be the correct size or else it will cause cycling. He performed the same test by using plyers to squeeze the bypass line (I called it an inlet...meant to the pump) and showed me how it would stop. He then installed the old one out of the old unloader. He told me they rarely go bad unless you get some larger debris in there that wears out the orifice changing the size and then it would create the same problem again.

Again...thanks for the correction. We appreciate getting the most correct information available posted for others to learn from.

Rod!~

[MMI Enterprises 289]

I hate restriction dependency with a passion.. Another example is the restriction needed on the main water inlet just past the float tank on older machines to make old style vacuum switch work the burner..what a PITA...Yea you can play with the vac switch by stretching springs and filing parts of the contacts inside as I think John made me learn a few years back but is no comparison in reliability to the flow or pressure type switches. John make sure boss man keeps me a reed in stock for the flow switches.. :)

But speaking of the cat unloaders.... do they all pretty much bypass some flow even when new?..when mine really started to go it bypassed maybe a third of my flow..

[One Tough Pressure 580]

I love my ZK1. Sma unloader for a wide variety of machines and no need to worry about the bypass line. My bypass is 1/2".