Error states & how to fix them

This article will guide you through the errors that can occur when using the Merlin400, and how to handle them.

First, let’s look at the different parts of Merlin400:

A: Extractor latch

B: Extractor lid + compartment

C: Tank latch

D: Tank lid + compartment

E: Oil glass

F: Elevator ring

G: Distiller lid + compartment

H: User interface (UI)

When Merlin400 is functioning normally, the arrow on the user interface (H) is green.
If an error occurs, the arrow changes to red – this tells you that something is wrong, and that you need to take action.

Merlin400 has 2 ways of telling you what the error concerns : Errors will show up in the app, along with a short description of how to handle it.

The user Interface (H) on top of Merlin400 will flash a red arrow symbol and a combination of one to four lights, indicating the nature of the error.

In the Merlin400 kit you will find a printed error code quick-guide – in most cases this will be enough information for you to handle the error, so keep that one with the rest of your accessories.
If, however, you need more in-depth information, please read on !

Merlin400 in error state

Merlin400 displaying error state
When an error occurs, the arrow will flash red, and the LED’s will display a combination of lights to tell you the nature of the error.

When entering error state, Merlin400 will stop any running program.

Resetting Merlin400 to normal state

Resetting Merlin400

When you encounter an error you should determine the reason, take the necessary steps to solve the problem, and then reset the machine.

Resetting Merlin400 is done by pressing and holding the selector (left) and the pause (right) button on the user interface simultaneously for 5 seconds. This will make the lights flash slowly, then fast. Merlin400 will reboot and – if the error is solved – enter ready state. This is shown by displaying the normal, steady green arrow.

UI: green arrow

No error

When the green arrow in the user interface (H) is lit, your Merlin400 is working and ready to use

An LED light will indicate which program is ready for launch.

The red gasket under the distiller lid, correctly in place
UI: red arrow, LED 1

Error: Leak in Distiller

Problem: The Distiller is not fully air-tight

Solution: Check that the two gaskets – one by the lid, and one where the distiller meets the oil-glass – are tight and in place. Tighten the elevator ring if needed.

The gasket can be removed for cleaning

If the gaskets are dirty or greasy from earlier extractions, they need to be cleaned to make sure they make an air-tight seal.

To clean the upper red gasket, remove the Distiller lid and the red gasket. Use a piece of cloth or toiletpaper soaked in isopropanol to clean the gasket, then put it back in place.

To clean the bottom white gasket, use a piece of cloth or toilet paper soaked in isopropanol to dry off any residue. Be careful to clean the backside of the gasket without damaging the fragile parts of the heater and elevator.

View into the extractor compartment, with the small red o-ring gasket at the bottom, and the upper gasket, in the lid.
UI: red arrow, LED 2

Error: air leak from extractor

Problem: The extractor is not fully air-tight

Solution: Remove the herb tuber and check that the small o-ring at the bottom of the extractor compartment is securely placed and clean. You can use the back of a screwdriver to push it in place.

Also, check the upper gasket in the lid is securely in place and clean.

If needed, you can use the syringe provided in the Merlin400 kit to remove isopropanol residue before handling the gaskets.

UI: red arrow, LED 3

Error: Alcohol gas level too high

The opening into the machine with the tube from the extractor lid is located at the left side of the lid

Problem: Fumes of the isopropanol alcohol can build up inside the Merlin400. The fumes, like the alcohol, are highly flammable, so the built-in alcohol sensor shuts the machine down before the fumes reach a critical level.

Solution: Dry off any IPA on the machine, especially around the extractor lid.

On the back of the machine you find the cooling fins. It is possible to blow fresh air in between the fins at the lower part.

Vent the inside of the machine – this can be done by blowing air in through one of the two structural openings in the chassis: one is the lower part of the cooling fins on the back side of the machine, the other is along the tube going from the Extractor lid (B) into the machine.

Warning ! the fumes you are venting are flammable, so keep open fire and sparks away.
Reset the machine after venting the inside. If the error persists, repeat this procedure. If the error still persists, wait 20 minutes, and try again.

UI: red arrow, LED 4

Error: Connection from Extractor to Distiller is blocked

Problem: The tube transporting the extract from the distiller to the extractor can become blocked.

Solution: Use the app to run program 5: “Vent Valves”. if this do not solve the problem, or if the you do not have access to the app, then disconnect Merlin400 from power and leave it off for at least 15 seconds. connect it again and performed an “extended cleaning” as described in the maintenance section of your user guide.

UI: red arrow, LED 1+2

Error: Heating plate error

The heating plate, located under the distiller

Problem: The heating plate does not work properly. Either the heat fuse is melted, or the elevator has been lowered too much, resulting in the wire connection being pulled out of its socket.

Solution: unplug Merlin400 from the power supply, wait 10 seconds, and plug it back in. This will bring the machine out of a possible software error-state.

If the error persists, contact

UI: red arrow, LED 1+3

Error: Pump needs cleaning

Problem: The pump has become clogged with residue from the extractions. This can lower the pump’s efficiency to a point where it cannot produce the necessary vacuum in Merlin400.

Solution: Run the ‘Vent Valves’ program from the app, and see if that solves the problem. If it does, then just continue using the machine.

If it is not enough, then follow this procedure:

  1. Clean the gaskets in the extraction and distillation champer.
  2. Insert and secure a collection glass with glass beads in the distillation chamber.
  3. remove the top lid of the distillation chamber and fill the collection glass with clean IPA.
  4. Run program 4: just distill

After some time the pressure will fall to under 200 mbar, and your Merlin400 pump is clean and back in business.

If you do not have the app up and running, just let the program run to the end.

UI: red arrow, LED 1+4

Error: Leak in Distiller (slow leak)

Problem: The distiller is not fully air-tight, and is slowly losing pressure. This error mostly happens during distillation.

Solution: Tighten the elevator ring if needed.

If the error occurs while distilling, be aware! that your Merlin400 is full of hot isopropanol. Carefully open the Distiller lid (G), avoid inhaling the isopropanol fumes, and check that the red gasket under the lid is in place.

Close the lid, reset the machine by pressing and holding the left and right button (select+pause) on the user interface (H).

When the machine has rebooted, resume distillation by choosing the program ‘just distill’ from the app, or by choosing the program from the user interface: press the selector button (left) until LED 4 (far right) is lit, then press the green arrow to run the distillation program.

If the problem persists, wait until the machine cools down. Then open the distiller, use the provided syringe to move your extract to a suitable container, and run the ‘Vent Valves’ program from the app. Alternatively, add 40-50 ml IPA to the Distiller and run the ‘Just Distill’ program.

UI: red arrow, LED 1+2+3

Error: insufficient vacuum for distillation

Problem: The distillation chamber cannot sustain a proper vacuum during the distillation process.

Solution: Check that the gasket under the Distiller lid (G) is in place and that the lid is tight.

If the error persists, clean the pump by adding 40-50 ml IPA to the Distiller and run the ‘Just Distill’ program.

If the error still persists, the pump is worn. Contact

UI: red arrow, LED 1+2+3+4

Error: Unknown error

Problem: Unknown…

Solution: Congratulations, you have found a bug we did not know of, and we need your help to fix it. Please open the app and navigate to Settings->Help->Send Machine Log and then write us an email at