PDQ Laser 4000 -Low Pressure Issue

[Westwood]

Looking for a little guidance, I have a Laser 4000 that begins spraying pre-soak on the car and halfway around the car it stops for five or six feet then start again. It does the same thing on low pressure wax. The part of the car (lt. side, rear, rt. side) it stops on moves from side to side. There is no holding tank for the chemicals so it is not running out of chemical. Most of the time the customer is unaware, but it is driving me mad. Any help or direction would be appreciated. Thank-You!

 

[madscientist]

Does the arch stop and then restart? Or does the arch move correctly but the product stops spraying and then starts spraying again?

 

[Westwood]

Sorry, I should have included that info: The arch continues to run at normal speed, the product is what stops.

 

[boywonder]

Almost sounds like the overhead hose is getting tied in a not. Check your low pressure check valves on the manifold as well.

 

[madscientist]

I think boywonder may have hit the jackpot.

 

[Westwood]

Thanks, I will check that, I just put a new overhead hose on about three weeks ago. The problem existed prior and after, however I had the new hose made same length as the old hose (43.5inches). But I debated, on the length as somewhere I had seen the measurement was to be 41.5 inches. Does anyone know actual requirement. I am of the opinion that you may have identified the problem, especially if 41.5 inches is the right length.

 

[dreese]

Looking for a little guidance, I have a Laser 4000 that begins spraying pre-soak on the car and halfway around the car it stops for five or six feet then start again. It does the same thing on low pressure wax. The part of the car (lt. side, rear, rt. side) it stops on moves from side to side. There is no holding tank for the chemicals so it is not running out of chemical. Most of the time the customer is unaware, but it is driving me mad. Any help or direction would be appreciated. Thank-You!

Check the water level in the solution tank / tank level float switch during the chemical pass. If you are running low on water during the chem pass or if you are getting an intermittent false read from the level switch, the solution pump will stop but the arch or bridge will keep going around the car. When the low level input goes away, the pump restarts. The only time it will stop all operation is if it gets the low tank level signal at the home position (before the pass / during the dump / etc).

 

[Westwood]

Thank You for your response, I will check this out and advise what I find. Thanks again for your time.

 

[gearhead]

Lo Pres issue

I have an M5 that was doing the same thing. 1st pass soap started out fine but when the arch got to the driver side rear quarter panal it looked as if the presure dropped about 3/4 of what it should have been. Fluid was still coming out but it was in a lite stream. Then by the time the arch was ready to turn and go back up the pass side it would return to normal. What i had found was that there was debris in my 2nd pass soap dema valve holding it party open. Replaced the diaphram and its now back to normal. Granted this is on an M5 but it think the chemical delivery is fairly similar. Im also assuming your LP pump never shuts off throughout the entire pass. I checked this by pulling one hose off at a time @ each injector and start a LP function in maintenece mode OTHER than the hose that is removed. If fluid comes out the barbed fitting you have a dema issue. If fluid comes out the hose then its a check valve issue.
BTW, Boom hose length on the 4000 is 43.5 in. end to end including fittings.
Hope this helps.

 

[newhampshiretech]

I imagine you have it resolved by now, but another possible low pressure issue is pump starvation. dirty screens in the low pressure supply tank will allow the soap etc to cover half the car then it runs out of flow.

 

[Westwood]

PDQ Laser 4000 - Low Pressure Issue

Thank-You for your comment. For the record, I still have not solved the problem. I will pull the screens and see if you are right. I hoping that's it.

 

[whitescout]

Does your machine do this on every wash everytime? Does it do it for both presoaks, or just one?

Does it do this when you test the presoak from the JO box?


If it is happening on every wash everytime, and with only one of the presoaks, you could have some debris blocking the inlet on the injector, or the check valve on the manifold. If you test the presoak by 100 enter 10 enter, watch the gage to see if the pressure increases, or decreases when this happens. If the pressure increases, I would look for restrictions, debris, blocking the dan foss valve, the injector, the check valve, or the "scrunchy" material in the foamer tube of the manifold. If the pressure decreases, I would look to see if the pressure relief valve on the manifold is faulty.

 

[dreese]

If this is happening on all lo pressure chem passes - starts OK, all solution quits but bridge / trolley continues to move, then solution comes back later in the cycle - I think either the float level switch (little grey paddle switch ) in the solution tank is starting to short out or you are physically running low on water level in the solution tank - especially if you can determine if the pump itself is stopping mid cycle. Did you try to jump out the X36 (Solution Tank Low Level) input and see if the problem goes away?

 

[JeremeWellborn]

Sounds more like the foam generator in the manifold is packed. I would be checking that along with solution check valves while you are in there. That's assuming you have made sure solution air pressure is not too high (I don't like it over 60psi)

 

[whitescout]

Sounds more like the foam generator in the manifold is packed. I would be checking that along with solution check valves while you are in there. That's assuming you have made sure solution air pressure is not too high (I don't like it over 60psi)

I suggested that in an earlier post, but the OP hasn't logged in since 5/24.

 

[Westwood]

Thanks for your responses, i will try everything you have listed this week and reply back.. Sorry for not replying soon, had several graduations, parties, etc., to deal with, just made me older. I do appreicate all of you who replied for taking the time to share your knowledge with me. Thank You!!

 

[asmbandits]

This is what it is, check all danfoss/dema valves on your solution manifold. There should be 4 or 5 of them, they are located on the pump station in a vertical row, take them off one by one and blow through them, if you can blow through them they are bad and need to be replaced, even one being bad can cause this issue , the chemicals eat away them over time. Im 80% sure this is your issue, other than that it could be your solution pump going bad, or the air pressure is not there either from the compressor not working properly or a air valve for the foamer not opening when it should. Also the check valves on the manifold above the machine could have gone bad and this will cause issues like you explain.

Check the valves on the solution manifold first this is what I check first and is the issue most of the time.

Either way its going to be one if not more of the issues I just laid out.