CET Xpress 1000Q Negative Pressure Issue

[schenkco]

We have a CET Color Xpress 1000Q UV printer but running into issues where the negative pressure does not go beyond the +0.3. As a result, I believe this is the reason behind our nozzle test showing up with gaps, faded colors, and extreme banding on prints. Everything that could go wrong went wrong this week. This symptom started showing up last week with a serious lag trying to get into the positive pressure. It sometimes would take upwards to 30 seconds just to hit +3.0. Our first suspicion was that the main pump has failed since we’ve seen the error message on the console. Typically we have ignored that warning and were able to print for the past 6 months just fine. When the problem occurred last week, we replaced the main pump but this did not correct the issue.

We’ve been in touch with tech support from CET and they suggested our tubing that lead to the print heads are blocked. He was right as there were tubes that had cyan ink inside them (see attached). We had enough tubing to replace out 2 colors but more tubing is on order. If this was the issue, one would think there would be some notable differences but sadly not. The tech support also suggested replacing the purge/ink prime button and adjustment valve (not sure what this is). Due to my inexperience with any large scale printers, I’m open to any other suggestions while we’re waiting for parts.

I’m trying to kill two birds with one stone with a question about replacement parts. One user on the forum had noted that “tomence, flora and cet used to be one and the same...”. Does anyone know if Flora parts would work in the CET printers? Of course I know we can’t compare apples to apples here..just because they look the same doesn’t mean they are.

Thanks!

 

[ExecuPrintGS]

You can try to take that negative pressure adjustment valve/ knob off and try blowing it out. Sometimes dust and crap gets in that.
We have chased negative pressure issues since day 1 with our cet hybrid and replaced tons of parts. It seems to level out for a while once we clean things out or replace the pumps but comes back again.

 

[schenkco]

Please excuse my ignorance. Which one is the adjustment that I need to take off? I've attached a photo. Thanks ExecuPrintGS!

 

[ChrisN]

On our Q5, the positive pressure pump is a separate pump in the carriage, and would not be fixed by replacing the negative pressure pumps. That one might be failing, which could be causing your slow positive pressure buildup.

We have chased negative pressure issues since day 1 with our cet hybrid and replaced tons of parts. It seems to level out for a while once we clean things out or replace the pumps but comes back again.

Interesting. We are currently having negative pressure issues, too. The pressure doesn't stay steady - it rises until it hits the cutoff, which causes some problems for over nights & weekends. What issues were you having?

 

[schenkco]

Thanks for your suggestion ChrisN. I've verified with CET that our 1000Q only uses negative pressure pumps (primary and secondary). The secondary kicks in if the primary fails. In your opinion, would you think the primary or secondary filter could be the culprit?

 

[ExecuPrintGS]

Interesting. We are currently having negative pressure issues, too. The pressure doesn't stay steady - it rises until it hits the cutoff, which causes some problems for over nights & weekends. What issues were you having?

Fluctuation of negative pressure while we printed and a lot over night. They said it was the environment changes overnight causing the fluctuation at night (getting cooler at night).
We have replaced pumps, switches, and a hand full of other things.
In CETs defense they have done a lot to help us out, including sending techs out. The 2nd tech made a bunch of adjustments to voltages and temps on the heads (to help a dropout issue we were having) and at that time replaced the negative pressure pumps and since that point we have been ok. We have had the machine almost a year now, id say the first 9 months it acted up, only the last 3 months has it run smooth for us.

But we never really did get a solid answer to why the pressure was fluctuating so much, or why the heads were dropping out for sure, just a "we did a bunch of things and hope it works"

 

[ChrisN]

Thanks for your suggestion ChrisN. I've verified with CET that our 1000Q only uses negative pressure pumps (primary and secondary). The secondary kicks in if the primary fails. In your opinion, would you think the primary or secondary filter could be the culprit?

Sorry, I can't help you. They must have changed the design with the newer printers.

Fluctuation of negative pressure while we printed and a lot over night. They said it was the environment changes overnight causing the fluctuation at night (getting cooler at night).
We have replaced pumps, switches, and a hand full of other things.
In CETs defense they have done a lot to help us out, including sending techs out. The 2nd tech made a bunch of adjustments to voltages and temps on the heads (to help a dropout issue we were having) and at that time replaced the negative pressure pumps and since that point we have been ok. We have had the machine almost a year now, id say the first 9 months it acted up, only the last 3 months has it run smooth for us.

But we never really did get a solid answer to why the pressure was fluctuating so much, or why the heads were dropping out for sure, just a "we did a bunch of things and hope it works"

Wow, that's exactly what our problem is. And they are blaming the environment in our case also.

 

[ExecuPrintGS]

Wow, that's exactly what our problem is. And they are blaming the environment in our case also.

They went after the environment first and foremost, saying its too dry and not consistent in temp. We got everything in spec for them and it still wasn't good enough.
We installed a $8000 humidification & RO system in our building to keep the humidity levels at 50% exactly and its climate controlled to 72* year round now.
When the last tech came out, it was about 42% humidity and he said that was way too low, even though that is "In Spec" its not "Ideal"

 

[signtech]

CET Xpress500H Manometer problems: Negative Pressure problems

New member here. First post. My shop is new to a large flatbed printer, and we purchased a slightly used CET Xpress500H that had sat for awhile. Went through all the movable parts. Replaced 4 heads to the Spectra Polaris PQ-512/ 15 AAA. Contacted the local CET representative and local supplier. We received some helpful info, but we are already in for quite a bit of investment, and we ran into an issue that doesn't seem to be covered in the manual or online after extensive searching. It seems like a trivial thing that a tech visit for a large bill just doesn't justify, so I come here for a pro to hopefully point me in the right direction.

We were able to print 6-48"X96" coroplast panels. Then the printer was shut down for the weekend, and then this morning we had pressure issues.

There is a Hi1, Lo2, Hi2, Lo1 setting on the manometer, negative pressure assembly, and I don't know the specified ranges, or the exact operation of it. There is some ink tint in the air tubes leading to the air/ink reservoir (for lack of better terminology), and I uncapped the pressure regulator tube on the back of the carriage, and bled about 1 pint of black ink out. Cleared the system. Zeroed out the pressure. Set negative pressure to -3.5, and set Hi 1 to 2.0, Lo1 to -3.8, Hi 2 to 2.0, Lo2 to -3.8. Pressure fluctuates, and triggers vacuum pump, but sometimes ciruit breaks the main vacuum pump, and I have to reset the pump on the computer control panel.

Any help would be greatly appreciated.

 

[ChrisN]

There is some ink tint in the air tubes leading to the air/ink reservoir (for lack of better terminology), and I uncapped the pressure regulator tube on the back of the carriage, and bled about 1 pint of black ink out. Cleared the system. Zeroed out the pressure. Set negative pressure to -3.5, and set Hi 1 to 2.0, Lo1 to -3.8, Hi 2 to 2.0, Lo2 to -3.8. Pressure fluctuates, and triggers vacuum pump, but sometimes ciruit breaks the main vacuum pump, and I have to reset the pump on the computer control panel.

The Lo-1 setting on the manometer controls the maximum negative pressure. When the pressure goes lower, the negative pressure pump cuts off to prevent ink being drawn back through the tubes from the heads into the negative pressure tank (which you drained of ink already). So if your pressure goes below -3.8, then the controller will shut off the pump. Once the pressure is higher than -3.8, then the pumps are turned back on with no need for a reset

The Lo-2 setting controls the minimum negative pressure. When the pressure goes higher, the secondary negative pressure pumps are activated, since the controller thinks the primary pumps have failed. Resetting the system in the control panel switches back to the primary negative pressure pumps again.

Since you have Lo-2 set at -3.8, the controller thinks the primary negative pressure pumps are broken since you try to set the negative pressure higher (at -3.5) than that. Try setting Lo-2 to -0.8 and see if that makes things better.

 

[signtech]

The Lo-1 setting on the manometer controls the maximum negative pressure. When the pressure goes lower, the negative pressure pump cuts off to prevent ink being drawn back through the tubes from the heads into the negative pressure tank (which you drained of ink already). So if your pressure goes below -3.8, then the controller will shut off the pump. Once the pressure is higher than -3.8, then the pumps are turned back on with no need for a reset

The Lo-2 setting controls the minimum negative pressure. When the pressure goes higher, the secondary negative pressure pumps are activated, since the controller thinks the primary pumps have failed. Resetting the system in the control panel switches back to the primary negative pressure pumps again.

Since you have Lo-2 set at -3.8, the controller thinks the primary negative pressure pumps are broken since you try to set the negative pressure higher (at -3.5) than that. Try setting Lo-2 to -0.8 and see if that makes things better.

That makes a lot of sense. Dialed in the new numbers and system seems stable. Thank you for the reply and description so I have an understanding of the internals. Up and running again.