Am I looking for something that doesn't exist?

Tony Shelton

Tony Shelton

BS Detector, Esquire
We just started using pressure washers a year ago to supplement our ultrasonic machine in cleaning permanent rooftop air filters.

I have a Landa 3500psi 4.7gpm hot unit that now has the dual lance. This is a variable pressure lance in that when you turn the handle, the flow reduces on the pressure nozzle size and is diverted to the low pressure side for soaping, etc. The pressure drops, but the gpm remains the same.

What I need is the ability (hopefully using the same type of twist handle) to be able to turn down both the pressure and the volume. Also, I'd like to be able to add detergent (in this case scents) at the wand and apply at the low pressure, low volume setting, then be able to go right back to high pressure as needed.

Am I looking for something that doesn't exist?

Thanks.

Tony
 
Brain Fart

Can it be that simple? I've got ball valves all over the place with my filtration etc, but I didn't think about using a high pressure ball valve.

Thanks. I am now officially an idiot.

What an introduction to the forum!

Seriously, thanks, I do think that will solve my pressure/volume problem.

Tony
 
Last edited:
Tony, Welcome to the forum.
Your machine runs at a constant rpm. So your gpm (flow) is constant. The gpm ( pressure ) is variable thru the dual lance handle or an unloader or by changing tips. To change the water volume ( flow) you will need to change the rpm of the motor. This would be difficult at the end of the wand. Also if you want to add chemical thru an injector, they are sensitive to flow. Basicly there is a venturi with a unique orrific sized to the volume of water. The right orifice matched with the right folw will give you the proper suction needed to draw chemical. How about a seperate flow jet type pump to deliver the chemical with?
 
I don't know what you mean with the reducer.

I need the low pressure, low volume for cleaning evaporator coils in cases where we are unable to block off 100% of the runoff. On condenser coils we can go all out at full pressure and full volume with no chemicals at all if done properly because condensers are made to drain on the roof.

We can do the same on evaporator coils when we are able to block off the ductwork and make the runoff go onto the roof. But in cases where we can't do that we have to use low volume/pressure while applying coil cleaner (very nasty) then rinse using the same volume/pressure.

A couple of minutes after doing an evap coil we might go right to a condenser. So I'm looking for something that I can switch at the gun. I'm sure the ball valve will work. Can I hook up an injector for the coil cleaner right before the gun and after the ball valve and shoot the coil cleaner through a 40 degree nozzle? That would be ideal.

Thanks,

Tony
 
Michael,
Thanks for your response. That's kindof the same thing they told me at the Landa dealer. But we have a homemade filtering system on our ultrasonic machine made from an above ground pool pump and filter. This pump is 40 gpm. Our ultrasonic machine only holds 66 gallons so 40 gpm is way too fast. My answer was to use a ball valve, turn it down partially till I lowered the flow to a reasonable rate of exchange. It has worked well for over a year without any kind of unloader.

It seems that since I am able to shut off my flow completely (by letting off the trigger on the gun) and the unloader takes over from there, that I should be able to dial down the pressure and volume with a ball valve and any excess pressure or volume will be release via the unloader. Am I wrong?

Thanks,
Tony
 
It does exists.

http://garagecleaning.net/Comparison.aspx We designed it six years ago, and built it 3 yrs later.

Out of the three ideas we had, we decided to go with the third suggestion. But take a look, maybe you can get this off the board and in use.

There is one of three ways I thought MIGHT have a chance.

1. You need to get a hydraulic flow control valve to redirect the flow back to your tank. This will take some engineering, but MAY have a chance. It will not be efficient and sure to have some set up issues, but it may work.

2. Have three small 2 GPM pumps connected to 1 hose. Run all 3, you'll have 6.0 GPM's. Turn one off and you'll have 4.0 GPM and so on.

You can achieve this two ways.
A) Have all pumps on a triple belt system. All belts/pumps running. Have a tee and High pressure Ball Valve set up to redirect any pump's water output back to the water tank you choose during operation

B) Have three separate systems complete with motors. Tee them together. By shutting one motor off you will reduce the flow to 4 GPM and so on.

3. Other than that, you will need a Hydraulic Drive System. They would run you about 35-40k.

Of those three suggestions, I know (#3) will work, (#2) has a 99% chance of working and (#1) 65+% chance of working.... depending on how mechanically incline you are.

Call me if you have any questions.
 
Hey I know when I slow down the flow on my whitco machine it gets some kinda hot.. ( Steam even ) Thank God for the thermostat... I guess if you lowered the throttle speed I have done this to rinse down the outside of vent hoods before , as not to blow the ceiling tiles away..
 
I don't think that the ball valve will work. LOok at the orifice or nozzle on your pressure washer, it is really small, and the machine will continue to pump at a constant rate trying to maintain the pressure that the unloader or regulator is set at. Your only option, as far as I am concerned, is to somehow reduce the pump speed. That is what Jim did with his hydraulic drive. The problem is that you have an air cooled engine, with direct drive, in a really hot climate. That means that if you reduce the engine speed, you will reduce the air flow. If you reduce the air flow, the engine will get hot and over time will have its service life significantly reduced. It also is not good for the pump to have water flow reduced, but it is easier to compensate for that than the engine.

Depending on the size of area that needs to be covered at the end, you have a few options, but really, all of them are a pain.
1. To have a seperate machine to pump the scents. You can use a little sure flow pump, but you would have to have either a seperate hose, or a solenoid at the pressure washer to switch between the two pumps. You will still have to clear the line of water before your scent comes up, and at low volumes, that will take a long time.
2. A pump up sprayer with the scent
3. A portable pump that you take to the area that you are working in.
 
Wow....the only problem with all three of those is that we are two or three stories up from the skid and usually about 200 ft away. We have to be able to go back and forth from low to high without going back to the machine.
Thanks,
Tony

Jim@Garagecleaning said:
It does exists.

http://garagecleaning.net/Comparison.aspx We designed it six years ago, and built it 3 yrs later.

Out of the three ideas we had, we decided to go with the third suggestion. But take a look, maybe you can get this off the board and in use.

There is one of three ways I thought MIGHT have a chance.

1. You need to get a hydraulic flow control valve to redirect the flow back to your tank. This will take some engineering, but MAY have a chance. It will not be efficient and sure to have some set up issues, but it may work.

2. Have three small 2 GPM pumps connected to 1 hose. Run all 3, you'll have 6.0 GPM's. Turn one off and you'll have 4.0 GPM and so on.

You can achieve this two ways.
A) Have all pumps on a triple belt system. All belts/pumps running. Have a tee and High pressure Ball Valve set up to redirect any pump's water output back to the water tank you choose during operation

B) Have three separate systems complete with motors. Tee them together. By shutting one motor off you will reduce the flow to 4 GPM and so on.

3. Other than that, you will need a Hydraulic Drive System. They would run you about 35-40k.

Of those three suggestions, I know (#3) will work, (#2) has a 99% chance of working and (#1) 65+% chance of working.... depending on how mechanically incline you are.

Call me if you have any questions.
Click to expand...
 
tonyshelton said:
Michael,
Thanks for your response. That's kind of the same thing they told me at the Landa dealer. But we have a homemade filtering system on our ultrasonic machine made from an above ground pool pump and filter. This pump is 40 gpm. Our ultrasonic machine only holds 66 gallons so 40 gpm is way too fast. My answer was to use a ball valve, turn it down partially till I lowered the flow to a reasonable rate of exchange. It has worked well for over a year without any kind of unloader.

It seems that since I am able to shut off my flow completely (by letting off the trigger on the gun) and the unloader takes over from there, that I should be able to dial down the pressure and volume with a ball valve and any excess pressure or volume will be release via the unloader. Am I wrong?

Thanks,
Tony
Click to expand...

Your unloader was not designed for that type of use. Your equipment will wear down faster than normal or become unreliable. All of your safety devices will be under possible strain. They were not designed for that.

Sorta of like taking a a small pick up with a I 4 gas engine and towing 35,000 lbs. across country with the rims squishing the tires to were the rims are almost touching the street. Will it tow it... possible. Will it last?

If your safety High Pressure switch fails to activate at the same time your unloader is being taxed out, don't be around the washer.

I would not recommend it.
 
Thanks Scott,

The portable sprayer route is what we are using now, both for scents on the filters and for coil cleaning chemical on the coils. I've got my lance set up with close quarters 90 degree angles at the nozzle so I can get into tight places and reach long distances. That's why I'd like to do everything from the gun.

Right now I have a (cheap) battery powered sprayer with a short (18 inch) wand. I can carry up one gallon of scent, two gallons of coil cleaner and bring an empty 2 gallon jug for rinse water. The injector for this cheap sprayer is attached to a jug lid that can be moved from one container to another. So, I spray on coil cleaner (to the best of my ability trying not to get burned by the chemicals with that little wand) wait a few minutes, then switch the lid over to the rinse water jug and rinse. This would be fine if it weren't for a few things:

1: No one seems to make battery powered portable sprayers that are rugged enough for the kind of severe duty we are putting them through.
2: Changing the lids from coil cleaner to rinse takes time and spilled coil cleaner is no fun. Time is money.

On the other hand, if I had the wand setup right I could

a: turn the flow down and lightly spray the coil cleaner on using the customized wand I already have. (takes about 4-5 minutes)
b: Turn the flow up to max, shut off the injector and clean the condenser coil. (takes about 4-5 minutes)
c: turn the flow back down go back and lightly rinse the coil cleaner off the evaporator coil with minimal water. (Takes about 4-5 minutes.

I'm already abusing the machine because it takes about 15 minutes to get the unit ready to spray, meanwhile the pressure washer has to run.
Then it takes about 10 minutes to put the AC unit back together, still the pressure washer has to run. Multiply this by 10-15 times per rooftop and you can see the machine runs a lot. (I do have the thermal relief valve sending water back to my tank)
I have a Valet Model 561R Remote car start (59.00) that I plan to install on the machine so it isn't running so much as soon as I have the time.

This is all about time (money) and convenience.

Thanks
Tony

Scott Stone said:
I don't think that the ball valve will work. LOok at the orifice or nozzle on your pressure washer, it is really small, and the machine will continue to pump at a constant rate trying to maintain the pressure that the unloader or regulator is set at. Your only option, as far as I am concerned, is to somehow reduce the pump speed. That is what Jim did with his hydraulic drive. The problem is that you have an air cooled engine, with direct drive, in a really hot climate. That means that if you reduce the engine speed, you will reduce the air flow. If you reduce the air flow, the engine will get hot and over time will have its service life significantly reduced. It also is not good for the pump to have water flow reduced, but it is easier to compensate for that than the engine.

Depending on the size of area that needs to be covered at the end, you have a few options, but really, all of them are a pain.
1. To have a seperate machine to pump the scents. You can use a little sure flow pump, but you would have to have either a seperate hose, or a solenoid at the pressure washer to switch between the two pumps. You will still have to clear the line of water before your scent comes up, and at low volumes, that will take a long time.
2. A pump up sprayer with the scent
3. A portable pump that you take to the area that you are working in.
Click to expand...
 
With a trap style unloader you can use a gun like this. In essence it is a metering type valve the reduces the flow which will reduce your pressure at the same time if you use the same tip. To maintain pressure you can go to a smaller tip.
 
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