Epson 4900 Maintenance question



I hope this isn’t a stupid question, or too redundant.
I have a 4900, a little over 3 years old, just past the extended warranty. It’s been pretty trouble free, but over the last several months it’s started doing automatic cleanings every few minutes–literally–if I’m printing a lot. I also go through periods where I get a lot of 0100 and 1433 error messages. I cleaned the wiper blade and capping station a couple of months ago, but it didn’t really seem to change anything. I did have a clog lately in the orange, which took a couple of days (cleaning, waiting, cleaning, etc) to clear.

I’m planning to change the dampers and wiper blade, although I didn’t buy a pump unit yet.
Would it be helpful to flush the print head as well? I know it’s somewhat preventive maintenance, but I can’t afford to replace this printer any time soon. What I was thinking was to do an initial fill with the piezo flush and let it sit for a day or two–will that do any good? (Since I don’t actually have any clogs currently it doesn’t seem necessary to take the head out, and besides I’m scared to….)

Is what the service manual calls “IS Unit” the dampers or the pump unit? And is it worthwhile to replace the dampers and wiper blade alone but not the pump unit?

Thanks very much for your time!

(I’ve got the set of refillable cartridges and the piezo-flush, as well as the service manual, adjustment program and PC notebook).


It really was a stupid question, huh?


As per the 4900 repair manual, the 1433 error is a sensor error. The manual says “Positions of the ink system components do not match with the sensor condition: 1. Connection failure of the sensor, 2. sensor failure or 3. IS Unit failure”. I’m not familiar with this error, or what to do about it, but from what I quickly read online, it’s a major error and requires printer repair by an Epson tech… Looking thru the repair manual, I see lots of references to the IS Unit, but no description to explain what is actually is or does, and photos pointing to it show a small cylinder shaped piece to the right of the capping station unit, which appears separate from the capping station assembly.

I recommend not manually flushing the print head if you don’t have any clogs- you could make things worse. It may be worth installing a set of refill carts filled with PiezoFlush, then running an initial fill cycle, then letting the printer sit for a few days to allow PF time to clean the internals of your ink system, but I can’t give you any advice/guidance in regards to your IS Unit error (sorry). Dampers should be replaced along with the flushing box, capping station and wiper blade about every 3 years, so it may be worth replacing these parts- BUT, not worth doing if your printer won’t function or is on it’s way out due to the IS Unit error…

Sorry I couldn’t be of more help.
Best regards~ Dana


Dear Dana, Thank you for your answer. I’m still digesting it. I actually haven’t seen those errors for a few weeks now, and the printer is working. I’ll try to contact Mardek, the local Epson repair place, maybe they’ll be able to advise something.
Thank you!


You are very welcome! It’s good that you haven’t seen those errors in a few weeks, and hopefully that means the issue corrected it’s self (?)

Best regards~ Dana :slight_smile:


Hi Dana, I called Epson about these errors and they said that as long as restarting the printer clears the errors, they probably don’t indicate a “life-threatening” problem, but probably a sensor error. I’ll do some more homework about the parts before I dig into the printer though.
Another question–are the flushing box and capping station part of the “pump unit”?
Thank you very much for your help!


I’m glad to hear it’s not a life threatening error :slight_smile:

Yes, the “pump unit” consists of the pump, capping station, flushing box and wiper blade:

Best~ Dana :slight_smile:


Dear Dana,
Could I ask another question, please? I’m getting ready to do the parts replacement, reading through the service manual and gathering tools, etc. The manual says, in putting back the damper unit, to tighten it with a torque screwdriver–is that necessary, since we don’t have one?
Thank you!


I don’t know for sure, since I’m not a certified repair tech, but have fixed many printers and have never used a torque wrench, so I don’t think it’s necessary, but you want to be careful to tighten enough, but NOT over-tighten or strip threading when screwing parts together.



Thanks very much! That’s what I wanted to hear! If you never used one, I don’t need one either!
Thank you!


You’re very welcome.


Just wanted to thank you for your help. I did all I planned to do–replaced the dampers, the pump unit (which is the IS Unit) and let some Piezo flush sit in the system for a couple of days. It took longer than I want to admit, but the printer is working great now. Thanks again!


You are very welcome, we’re here to help, and I’m happy to hear your printer is working well again!

Best regards and happy printing~ Dana :slight_smile: