Epson ET-8550 DTF Conversion: Are 2mm "Y" Connectors Universal, and How to Clean & Reuse an Old CISS System?

Question:
I'm on your website looking for the 2mm connectors and Y-connectors. I see you carry them, but I need to know if they're a universal fit. I have an Epson ET-8550 converted to DTF, and I also have a bulk CISS system I want to reinstall, but it hasn't been used in about a year. What's the correct way to clean it so I can reuse it? I believe my tubing is 2mm (I circled the connectors I need in a photo). Also, I recently bought FFC cables from you and even mentioned your business in a YouTube video.

Answer:

1) Are the 2mm connectors and Y-connectors "universal"?

They're not universal in the sense of "fits everything", but they are standardized by tubing size-so if you match the connector to your tube dimensions, they fit reliably.

Connectors are typically defined by:

• ID (Inner Diameter): the size of the opening inside the tube where ink flows

• OD (Outer Diameter): the outside size of the tube (less commonly used for these small barbed connectors)

Because people constantly mix-and-match tube brands, I created a simplified shorthand system:

• C2 = 2mm ID tubing / connectors

• C3 = 3mm ID tubing / connectors

So the rule is simple:

• If your ink tubing is 2mm ID, buy C2 connectors/Y-connectors.

• If your tubing is 3mm ID, buy C3 connectors/Y-connectors.

2) What size is usually used on DTF setups (especially white)?

Most DTF systems commonly use larger tubing for white ink flow, and in many builds that ends up being C3 (3mm ID) because white ink is thicker and benefits from less restriction.

However, not every conversion is the same. Some ET-8550 conversions (and many CISS kits) use 2mm ID lines throughout, especially if the kit was designed around compact dampers/manifolds.

3) How to confirm if you have 2mm or 3mm tubing (quick & practical)

Since the terms "2mm tubing" online can be confusing (some sellers describe OD, some describe ID), the best way is to confirm ID:

• If you have calipers, measure the inner opening of the tube.

• If you don't: remove one tube and compare it to a known connector spec (2mm vs 3mm). A true 2mm ID tube looks noticeably tighter and smaller internally.

Important fit note:

• A 2mm connector in a 3mm tube will be loose and can leak or introduce air.

• A 3mm connector in a 2mm tube usually won't insert properly (or will split the tube).

So matching ID is what matters most.

4) Reinstalling a CISS that sat unused for a year: what usually happens

If a CISS sits for a long time (especially with pigment or DTF inks), you can get:

• dried ink plugs inside the tube

• sludge/settling (especially in white ink lines)

• sticky check valves or dampers

• air leaks from hardened grommets or loose connections

That's why the "clean it and reuse it" plan is doable-but it needs to be done carefully to avoid pushing debris into the printhead.

5) A safe, sensible cleaning approach (high-level guidance)

Since your goal is to reuse tubing and connectors, cleaning typically involves:

A) Don't send old ink into the printer

Before you reconnect to the printer, you want the system flushed so any dried ink doesn't migrate into the head.

B) Inspect and replace what's cheap and failure-prone

Even if you clean perfectly, these parts commonly cause problems after storage:

• brittle tubes

• loose/expanded tube ends (won't seal on barbs anymore)

• worn O-rings, grommets, or one-way valves

• dampers that no longer flow evenly

If any tube is cloudy with residue, feels stiff, or has "permanent bends," it's often better to replace that segment.

C) Flush the CISS lines with the correct cleaning fluid

For DTF and pigment setups, you generally want a compatible cleaning solution (not harsh solvents that can damage plastics). The idea is to dissolve/soften old ink in the lines.

A best practice is to flush each line individually so you can see that it's flowing clean, then flush again until the output is clear and consistent.

D) Drying and re-priming matter

After flushing:

• You don't want pockets of air.

• You don't want leftover cleaning fluid diluting ink too much (especially white).

Once it's clean, the system typically needs to be properly primed so ink reaches the dampers/ink inlet without large air gaps.

6) Which connector should you buy for your circled parts?

Based on your note that your current tubing is 2mm, you'll want:

• C2 straight connectors

• C2 Y-connectors

If you later find your white line is larger (common on some builds), then it might be:

• C3 for white

• C2 for CMYK
  ...but only do that if your tubing IDs actually differ.

Addressing printer issues can be a complicated affair due to the hands-on nature of the problems, and small physical factors (tube sizing, air leaks, dried ink, valve behavior, and priming) make a big difference in results. Because of that, we're not able to provide remote troubleshooting, suggestions, or support for printer repairs. We offer an in-person evaluation and repair service via our local diagnostic facility: Printer Repair Service (https://bchtechnologies.com/printer-repair-service). Given the high demand, we operate on a first-come, first-served basis, so it might take a few weeks before we can get your printer in for a drop-off. Our services are structured to repair either a whole printer or specific parts, with clear instructions on how to proceed. However, we understand our rates aren't the most economical, so we strongly encourage self-help via online research. You can start by checking out YouTube or visiting our YouTube channel's homepage: BCH Technologies YouTube Channel (https://youtube.com/@bchtechnologies). Look for specific videos using the search icon next to "About" on the right-hand side of the menu bar. I receive dozens of queries every day asking about videos for specific topics, and after creating videos over the past nine years, it's difficult to remember every single one-so YouTube's search feature is the fastest way. Plus, YouTube may suggest helpful videos from other channels that match your exact situation.

Thank you again for your support-especially for mentioning us in your video-and for purchasing the FFC cables from us. If you match the tubing ID (C2 for 2mm, C3 for 3mm), you'll be in the right connector family for your ET-8550 DTF setup and your CISS rebuild.