Extended Pressure Build-up

[rick77 14]

When I got my machine the directions said to not let it run more than 30 seconds without releasing the water pressure from the gun.

What's the longest amount of time you typically let the water pressure remain without pulling the trigger on the gun. Is this really that bad for the pump and motor on the power washer?

[Paul Kassander 26]

It will cause the water to get hot and damage the pump after about a min or so depending on the length (amount of water in) of the bypass (internal or external line).

If it has a external bypass line you can run it back to your tank or to the ground and then you will not have to worry about it running in bypass any longer.

[rick77 14]

Is this external by-pass line something that you can add to your machine or is it more of a special design on high end pumps or power washers. I'd like to add this feature to my machine if it can be done.

Thanks!

[Timo 25]

Is this external by-pass line something that you can add to your machine or is it more of a special design on high end pumps or power washers. I'd like to add this feature to my machine if it can be done.

Thanks!

Yes, it can be added fairly easily to most commercial rated machines. Not so easily to those machines that have a built in unloader.

Do you currently use a float tank for your machine? If so, you can plumb the bypass back to your float tank and waste no water at all.

If you do not use a float tank, then you can dump to the ground, but that does not always create the appearance that you want to maintain.

Post a picture of your unloader/pump and someone will be able to guide you through the process.

[rick77 14]

My machine is a very low end so-called "commercial" power washer. It's a Husqvarna 3000 psi 4 gpm. It's working great being that I'm primarily a window cleaner and only power wash for some of my window cleaning customers.

But the machine does have a Cat pump. I'm not sure if it has a built in unloader or not. I'll have to check the owner's manual and find out more about it.

[Paul Kassander 26]

If the unloader is "built in" on the pump then no. If it can be removed and changed then yes.

If the unit has an external line like first pic that goes from the unloader to the inlet, that hose can be disconnected from the inlet (plug opening in inlet where it was) and run to the ground or tank. (the black hose that is opposite of the thermal relief valve-red barb on the unloader)

If it has a control set unloader like second pic. then you will have to replace it with a standard unloder to bypass back to tank.

Edited April 9, 2009 by Paul Kassander

[rick77 14]

If the unloader is "built in" on the pump then no. If it can be removed and changed then yes.

If the unit has an external line like first pic that goes from the unloader to the inlet, that hose can be disconnected from the inlet (plug opening in inlet where it was) and run to the ground or tank. (the black hose that is opposite of the thermal relief valve-red barb on the unloader)

If it has a control set unloader like second pic. then you will have to replace it with a standard unloder to bypass back to tank.

Paul, the unloader on my machine is like in the second pic. I'm not sure whether it can be replaced or not. Hopefully it can.

Thanks for the info!

[rick77 14]

So unless I replace the unloader on my unit I'm stuck holding my gun so I can pull the trigger at least every 30-40 seconds, or run back to the truck and cut the machine off if I need more time-out than that.

What's a ballpark price on a regular unloader for a Cat pump?

[Paul Kassander 26]

Just about any unloader will work for you as long as it meets the pressure and flow rates of your pump.

They run anywhere from $39 for a pulsar unloader to over $400 for a K9 unloader. For your unit the $39 unloader is a good choice, you can get them with a knob on them or change to a flow actuated unloder for a bit more $ but that may not be necessary for you, it just comes down to personal preference.

[rick77 14]

Just about any unloader will work for you as long as it meets the pressure and flow rates of your pump.

So my machine being 3000psi and 4gpm, I would match the unloader to these numbers?

Thanks!

[Paul Kassander 26]

At a minimum you can get one rated higher and it will work just fine.

[rick77 14]

At a minimum you can get one rated higher and it will work just fine.

Thanks for the valuable info and for your time Paul!

I really do appreciate it!

[FullBlast 14]

Burnt my pump one time by letting sit in bypass and that was the last. I have all of mine runnin back to the tank. You can let it sit and run all day if you want.

Worth the money and time to change it.

[RMedbery 26]

I wonder how hot water gets (roughly) when its in bypass? I ask because my cat pump has been going for about a year now running exclusively on hot water. Anywhere from 110 to about 190 degrees depending on location. It also runs in bypass every night on every job for about 5 minuets at the longest (getting hose from kitchen to roof). I put a 1 foot bypass hose on it, the pump does not have a hot seal kit. I have another electric cat pump with internal bypass thats pushing 2 years old, again run exclusively on hot water. Conversley, long ago I had a cheapo general EZ pump, I accidentally hooked it up to hot water once (didnt know outside spigot was hot). Half way through the job it wasnt building pressure, the pump never performed right again.

My point is, you say you have a cat pump, you use it seldomly, I wonder if you have to do anything at all?

Edited April 11, 2009 by RMedbery

[rick77 14]

My point is, you say you have a cat pump, you use it seldomly, I wonder if you have to do anything at all?

Most houses I do are very large with many situations where I have to pause the gun for a bit.

Since I only have one power washing machine I'm wanting to change the unloader to an external bypass to be on the safe side and not damage the pump.

Being a primarily a window cleaner I don't use the machine everyday like most of you guys but on the days when I am using the power washer the extra feature of external bypass would probably pay for itself by eleminating that one time that the pump would have burnt up due to too much time in internal bypass mode.