View Full Version : Water Error on Shenhui

Martin James
07-05-2014, 8:08 AM
I am getting an intermittent water protection error on my shenhui dual tube.
I am currently only using one of the tubes. Last night i started a 30 minute job engraving plywood and after about 5 minutes the laser stopped with the screen reading "water error". For any error you can reset the machine and the job should restart where it left off.

My cooler is the CW5200 for dual tubes, it runs water through both tubes, and the laser has 2 protection switches, one on each tube loop.

Sometimes after a reset the laser would start again and sometimes not. It seemed to run better if powered off the board.

If the error happens, then I try the pulse laser button the error then reads "water error 1"

Could this be a moisture problem. There is a possibility that one of the water connections near to the protection switch leaks. (Not enough to identify which one leaks, I need to re clamp all of them)

Do i need to replace both switches? Since i don't know which one is faulty?

any ideas would help. Thanks. Marty

Dan Wilhelm
07-05-2014, 10:45 AM
It may just be a failing pressure switch. My GWeike actually came with a spare pressure switch, which leads me to believe that it is a part that commonly fails. If you have access to an ohmmeter or multimeter, check the resistance across the terminals on the pressure switch with the water pump on and off. In one state, it should read <0.5 ohms, and in the other it should read "OL." I'm not sure if it is a normally open or normally closed switch, but as long as it is changing state, it should be fine.

Martin James
07-05-2014, 10:24 PM
Hi Dan, thanks for the help. I will disconect the wires and try the ohm meter.

Does anyone with a dual tube shenhui know if a failure in one sensor signals the board to prevent either tube from firing?

The pulse button fires both tubes, which has me thinking that the protection switches are also linked together by the software.

Thanks Marty

Martin James
07-06-2014, 11:37 AM
Joy the Shenhui tech recently has quit or was fired from Shenhui, so i am getting my support from the sales person.
I have been told that maybe i should get a pond style pump to use with my laser as the cw5200 might not have enough water flow to keep the water protection switches open. ( replace $900 chiller with $40 pond pump) This would explain the intermittent functioning.
So I looked up the specs on the 5200, it looks like it has a better compressor for cooling than the CW5000, but has the same pump. 300 watts, 10 L/Min, 10 meter head. If it is the same pump as the 5000 but the flow is split in half, then I can understand how there could be less water pressure on the switches.

I am going to try cutting my in and out hoses shorter to reduce friction losses. I already elevated the cooler and I think that helped.
Comments appreciated. Cheers. Marty

Dan Wilhelm
07-06-2014, 9:20 PM
I'm not sure how the cw5200 is configured (I just run room temp water through my laser tube, and have had no overheating issues), but I would think you could put the $40 pond pump between the chiller and laser to get the pressure up at the tube, but keep at least some cooling effect from the chiller. You could run the chiller into a small reservoir, then put a pond pump in the reservoir. The chiller would provide the "make up" water and a somewhat low temperature, and the pond pump would provide adequate pressure. The chiller might not be able to keep up with the amount of water coming from the tubes, though. It might work putting the pond pump between the outlet of the laser tubes and the chiller, but I doubt it.

Rich Harman
07-07-2014, 2:13 AM
The CW5000 has an alarm output that you can use instead of the flow sensor(s) on the laser. I assume the 5200 does also. You would just need to wire it up to the main board.

If there is only one pump split between two cooling loops and if only one tube is used at a time I see no problem with having the tubes plumbed in series - using just one loop, plug the other. It doesn't make sense for it to be that way though - water will flow more where there is the least restriction, that would be a bad design.

George M. Perzel
07-07-2014, 6:45 AM
It may sound a bit weird but run a ground wire to the metal part of both flow switches. I had a problem where the laser button would not fire and that solved it-advice from Shenhui.
Good Luck
Best Regards,

Martin James
07-09-2014, 3:56 PM
Update on my water error issue. I went in last night and wired a ground to both switches, then I raised the cooler up on several courses of cinderblocks so that the pump is more or less at the height of the tubes. I cut the silicon water tubes in half to the shortest possible length so as to reduce friction losses. According to the online plumbing calculator I used that should have given me an extra 10 to 15% head pressure.
None of this helped. I have tried both tubes. I think the water protection must need to be valid for both to get either to fire.

Then I decided to drain off the coolant. I am using a 30/70 mix of propylene glycol and distilled water. I then refilled with distilled water. When I went to check the tube for bubbles, I noticed a a bug or some other piece of junk travel down the middle of the bigger tube. Then after a bit it swam back the other way in the smaller tube.

sound of flushing.....

Now back to lasering. I had thought that clearing a bug would be the problem, but i am still getting the same results. The job will start and then after a minute or 2 the laser stops and requires a reset. After the reset you have the choice to restart the job from the stopping point or escaping. The laser will restart about 1 in 6 resets.
On my board there is also a button called start pause, This button is for repete jobs, it will run the last file. When I restart the job from that button I am getting a much higher start rate, like 1 in 3, or about double the success rate as starting the job from reset of from scratch. I would think that if i was having a purely mechanical problem that both rates would be the same. Could this be a soft wear problem?
This is Laserworks ver 5.0037, is that current?

I wanted to check the switches with a meter, but when I crawled in there it looks like the wires have no extra slack and are shrink wrapped, or on the other end have hot glue on the terminals. I would probably have to cut the wires then resplice them to do the test. I honestly do not think I have a water pressure problem, the CW5200 has a very strong. When I test the alarm by pinching the tube I have to pinch hard and almost close off the flow to make the beeper sound.

Does anyone have a picture of the wiring of an alarm cable into the RD320 board? I am not very good at understanding electrical schematics.

Thanks everyone for the extra help.