Epson ET-8550 Printhead FA09231 and Proper CISS Pump Usage

Question:
I have an Epson ET-8550 where one white channel is only printing with half of the nozzles. Do you carry the FA09231 printhead or repair them? If not, do you know where I can buy new ones? I actually need two of them. Do other Epson printheads work as substitutes since some are just renamed? Also, I purchased your CISS system and a new pump. What is the correct way to run the CISS-should it run all the time, only when not printing, or at specific intervals?

Answer:

1. Epson ET-8550 Printhead FA09231 Availability and Alternatives

• The ET-8550 uses the FA09231 PrecisionCore printhead, and unfortunately, we do not sell or repair these printheads at BCH. Epson does not release these heads as readily available parts for third-party distribution, so the most reliable sources are Epson-authorized service centers or salvaged units from donor printers.

• While some Epson printheads may appear physically similar and are sometimes renamed versions across different models, the FA09231 has specific chip IDs and nozzle configurations. Attempting to swap in another printhead, even from a similar Epson series, usually results in recognition errors or improper functioning. For that reason, replacements must be the exact FA09231 head.

• If only half of the nozzles are firing, this typically indicates either a severe clog or burned-out nozzles. Minor clogs can sometimes be managed with flushing or professional cleaning, but burned nozzles cannot be recovered. In those cases, replacement is the only option.

• As a possible workaround, some users try color rotation on the printhead, which involves reassigning colors in the channels to bypass a failing one. I have videos on this subject on my YouTube channel (https://youtube.com/@bchtechnologies), which may provide you with a helpful starting point.

2. Correct Way to Run the CISS System with Pump

• A Continuous Ink Supply System (CISS) feeds ink passively while printing, and the pump is used primarily for priming and re-priming the system.

• When to Use the Pump:

  • During initial installation, to draw ink through the tubes and eliminate air bubbles.

  • After replacing or refilling cartridges/dampers, to restore proper ink flow.

  • If you notice air bubbles or gaps in ink lines that cause nozzle gaps in test prints.

• When Not to Use the Pump:

  • Do not run the pump constantly or as routine maintenance. Overuse can cause over-pressurization, leaks, or even flooding of the printhead.

  • The CISS system should not be pumped while the printer is idle. Once primed, it will supply ink passively whenever the printer operates.

• General Rule: Run the pump only as needed-mainly when installing or troubleshooting-not as a continuous or scheduled process.

Addressing printer problems like these can be complex, as they require hands-on diagnosis and sometimes replacement parts that aren't easy to source. That's why we cannot provide remote troubleshooting or repair support. However, we do offer an in-person evaluation and repair service (https://bchtechnologies.com/printer-repair-service). This service is first-come, first-served, and because of high demand, it may take a few weeks before we can get to your printer. We repair both complete machines and specific parts, but we also acknowledge that our pricing isn't always the most economical. For many customers, self-help through research is the best approach. A great resource is our YouTube channel (https://youtube.com/@bchtechnologies). Use the search function next to the "About" tab to locate videos on CISS installation, color rotation, and Epson troubleshooting, or let YouTube recommend additional related content from other experts.

Thank you again for your thoughtful question and for supporting our work. Your engagement helps us continue building technical resources for the printing community.