Epson L1800 DTF: Air Bubbles Coming From the Capping Station and Two Red Lights Blinking (Fatal Error Mode)

Question

I'm using an Epson L1800 for DTF printing. For the past two weeks, we've had ongoing color printing problems. We tried everything we could based on your videos, but now we're seeing large air bubbles coming out from the cap (capping station area). After that happens, the printer goes into fatal error mode with two red LEDs blinking. What's causing this, and what should we do next?

Answer

From what you described, you're dealing with two separate issues that can be related but should be diagnosed independently:

1. Large air bubbles "regurgitating" from the capping station / cap area

2. Two red LEDs blinking (fatal error mode)

Let's go through both in a practical, cause-and-effect way.

Issue 1: Epson L1800 "Regurgitating" Large Air Bubbles From the Capping Station

In most cases, this symptom is not caused by "air in the ink lines." Instead, it points to a partially clogged capping station and/or restricted waste ink path (cap top → pump → waste tube → waste tank).

Here's what's usually happening mechanically:

• At the beginning of a cleaning cycle, the pump is able to pull a little liquid/ink through the cap top.

• As that ink reaches a restricted section (clogged cap top chamber, clogged pump path, kinked/blocked waste tube, or a saturated waste pad/tank path), flow becomes choked.

• The motor continues turning the pump. With the fluid path restricted, the pump starts compressing air and pressure in the waste line instead of moving liquid smoothly.

• When the motor stops, the built-up pressure releases backward, and that's when you see the air bubble shoot back and "burp" out at the cap area.

This is also why some people hear a squeal/screech or struggling sound during cleaning-the pump is fighting resistance. The following videos explain that "struggling pump" behavior and the sound symptoms:

• Screeching sound video 1 (https://youtu.be/MjArYM-QnfU)

• Screeching sound video 2 (https://youtu.be/TNOG_1TtN6g)

What you should inspect first (high-impact checks)

These are the most common choke points that cause bubble regurgitation:

• Cap top (capping station) partially clogged: DTF ink and pigment load can sludge the cap top chamber and the screen/filter area.

• Waste tube restriction: Pinched tube, thick ink buildup, or dried ink plug inside the tube.

• Pump / peristaltic assembly restriction: The pump can lose efficiency or become internally contaminated, so it can't move thicker waste smoothly.

• Waste bottle/tank path blocked: If the waste bottle line is blocked or the waste pads are saturated, backpressure increases.

Videos that help with the capping station (removal, cleaning, maintenance)

These guides match the exact failure mode you're describing:

• Removing and Installing the Capping Station (https://youtu.be/_cZEkmgIZYc)

• Unclogging the Capping Station (https://youtu.be/WbY_6O1-w2c)

• Capping Station Maintenance (https://youtu.be/5yjq3ZN0qv8)

• Repairing the Capping Station (https://youtu.be/5UC2IMu9V90)

• Rewiring Capping Station Tubes (https://youtu.be/J9im3s8UJfo)

If none of those work, we also have an in-depth paid guide that breaks down the capping station down to individual gears and shows correct reassembly here: Capping station assemble/disassemble guide (https://bchtechnologies.com/products/video-capping-station-assemble-disassemble-guide-for-l1800-1390-artisan-1430-and-1400).

Important caution: Avoid repeatedly running strong cleanings when you see bubble regurgitation. If the waste path is restricted, repeated cleaning can increase pressure stress on the pump system and can even worsen leaks, overflow, or internal contamination.

Issue 2: Two Red LEDs Blinking (Fatal Error Mode) - Identify the Exact Error Code

On the Epson L1800, two red LEDs blinking indicates a general/fatal error state, but it does not tell you the real cause by itself. To troubleshoot correctly, you need the printer's specific stored error code.

The best way to retrieve that code is by using Epson's technician utility often called the Adjustment Program.

How to check the stored error code (Adjustment Program method)

1. Open the Adjustment Program and select the USB port with your printer's name from the dropdown menu.

2. Choose Particular Adjustment.

3. Scroll down and select Printer Information Check.

4. Click Check.

5. The most recent stored fault is typically listed at the top as error number one.

Once you have the code, interpretation matters. Epson uses what we often call "triple secret error codes" (because the consumer-facing lights are vague, while the service code is specific). A code might point to something like an APG sensor (paper gap), a PF/CR encoder issue, a carriage/CR motor fault, an ink system/pump issue, or even a waste ink counter / maintenance-related fault-each requires a different response.

To interpret the code, search "BCH Epson Error" on Google and look for our page explaining Epson's technician-level codes and what they usually mean.

If you want a quick walkthrough of the process, here's a short video showing how it's done: Adjustment Program walkthrough short (https://youtube.com/shorts/FPZzpyYuZLE).

Note: This Adjustment Program is typically provided to Epson technicians, but it is sometimes distributed by DTF printer sellers. If you don't have it, you may need to search online for a copy from your vendor or other sources.

Why these two problems can show up together

A restricted waste path/capping station problem can contribute to cleaning failures, pressure irregularities, and ink overflow/contamination risks. Meanwhile, the two-red-light fatal error could be triggered by something separate (sensor, carriage movement, encoder contamination, pump errors, waste ink count, etc.). That's why it's critical to (1) address the cap/waste restriction and (2) read the stored code rather than guessing.

Addressing printer issues can be complicated because these problems are hands-on by nature. So, we're not able to provide remote troubleshooting, step-by-step suggestions, or repair support from a distance. We do offer an in-person evaluation and repair service through our local diagnostic facility, printer repair service (https://bchtechnologies.com/printer-repair-service). Due to high demand, we operate on a first-come, first-served basis, and it may take a few weeks before there's an opening to drop off your printer. Our services are structured to repair either an entire printer or specific parts, with clear instructions on how to proceed. However, we recognize our rates aren't the most economical, so we strongly recommend self-help through online research first. You can start by checking YouTube or visiting our channel homepage at BCH Technologies on YouTube (https://youtube.com/@bchtechnologies). Use the search icon next to "About" on the right-hand side of the menu bar to find videos on very specific topics. I receive dozens of messages every day asking which video covers a specific issue, and after nine years of creating content, it's difficult to remember every single one-so YouTube's search function is the fastest method. As a bonus, YouTube may also recommend relevant videos from other channels that can help.

Thanks again for reaching out, and thank you for supporting BCH Technologies and our YouTube content. I truly appreciate it.