Epson ET-8550 Printhead FA09231 Issues and Proper Use of a CISS System

Question:
I have an Epson ET-8550 where one white channel only has half the nozzles working. Do you sell the FA09231 printhead or offer head repairs? If not, do you know where I can get new ones? I actually need two FA09231 heads. Do other Epson printheads work as replacements since some are just renamed? Also, I bought your CISS system and recently purchased a new pump from you. What's the correct way to run the CISS-should it run all the time, only when not printing, or at certain times?

Answer:

1. Printhead FA09231 Availability and Compatibility

• The Epson ET-8550 uses the FA09231 printhead, which is a specialized PrecisionCore head. Unfortunately, Epson does not make these printheads widely available for retail sale, and we do not stock or repair them at BCH.

• The only reliable way to obtain a new FA09231 is through Epson-authorized repair centers or by salvaging from another ET-8550 (or compatible model).

• Some Epson printheads do share design similarities, but compatibility depends on the firmware, nozzle arrangement, and chip ID. Even if two heads look identical physically, they may not function in place of each other unless they are from the exact same model family. For the ET-8550, the FA09231 is the only safe option-substituting with another series head will almost always trigger recognition errors or fail to align properly.

• If only half the nozzles are working, this usually means permanent nozzle burn-out or severe clogging that flushing won't fix. In such cases, replacement is unfortunately the only solution.

2. Proper Use of the CISS System with Pump

• A Continuous Ink Supply System (CISS) needs to maintain stable ink flow, and your newly purchased pump helps with priming.

• When to Run the Pump:

  • Use the pump only during setup or after replacing cartridges/dampers to prime the lines and remove air bubbles.

  • If you notice gaps in nozzle checks caused by air entering the system, you can use the pump again to re-prime.

  • Do not run the pump constantly or as routine maintenance. Continuous pumping can over-pressurize the system, cause leaks, or flood the printhead.

• During Regular Printing:

  • The CISS works passively, feeding ink as the printer consumes it. As long as the ink tanks are properly vented (air plugs open) and the tubes are free of kinks, no extra pumping is needed.

• When Not Printing:

  • Simply leave the CISS connected. Make sure the air vents remain open, but keep the printer in a stable environment to avoid introducing air into the lines. There's no need to run the pump when the printer is idle.

Addressing printer issues can be a complicated affair due to the hands-on nature of the problems. That's why we cannot provide remote troubleshooting or direct printer repairs. However, we do offer an in-person evaluation and repair service (https://bchtechnologies.com/printer-repair-service). Because of high demand, service is provided on a first-come, first-served basis, and it may take several weeks before your printer can be processed. Our repair services cover both entire machines and specific parts, though we acknowledge that our pricing is not always the most economical option. For many customers, self-help research is often the best approach. A great place to start is our YouTube channel (https://youtube.com/@bchtechnologies). You can use the search icon next to the "About" tab to find videos on CISS setup, ink flow troubleshooting, and Epson repair tips, or let YouTube recommend related videos from other experts.

Thank you again for your detailed question and for supporting BCH Technologies. Your engagement helps us continue creating resources to assist the printing community.