Filling the Cooling Circuit

Required Tools & Equipment

  • Deionized water, 1.8L
  • A coin or large flathead driver
  • A small flathead screwdriver
  • Clean jug, pitcher, bottle, or otherwise similar container for water/coolant
  • Small funnel (from Box A)
  • 2 bottles of coolant (from Box A)

Preparing the Coolant

Deionized water, commonly referred to as DI water, is required to fill the cooling circuit. AON3D does not provide DI water with each machine and it is up to the end user to purchase the water.

Deionized water and distilled water are not the same product. Please ensure that only deionized water is used to mix the coolant.

Do not use regular tap water or any other coolant mixture not authorized by AON3D. With improper cooling fluid, potential failure mechanisms include: galvanic corrosion, algal growth, scale formation, and polymeric degradation. Any or all of these mechanisms will negatively affect the performance of the cooling system and can lead to catastrophic component failure.

Mix the DI water and coolant concentrate in a separate container (ideally a pitcher with a narrow lip for easy pouring). The ratio of DI water to coolant should be 9:1. The bottles of coolant provided with the AON-M2 are 100mL. Mix 2 bottle of coolant with 1.8L of DI water to get 2L of coolant solution.

The cooling system takes about 1.3L of coolant solution to fill it, so you should expect to have coolant solution left at the end of this process. Keep this solution to top up the system over time.

Initial Gravity Fill

Disconnect the power cord shown in the figure below to turn off the pumps.

Pump motor power cord

Start by opening the fill port of the pump reservoir with a coin or a large flathead driver. Using the included funnel, pour coolant solution into the circuit until the reservoir is almost filled to the top.

Once filled, set the red speed controller dials, numbered from 1 to 5 and located on the rear face of the pump motors, to number 3.

Pour the coolant at a slow and steady pace to ensure that the coolant mixture does not spill.

Fill the pump

Pump Fill

Set the red speed controller dials, numbered from 1 to 5 and located on the rear face of the pump motors, to position 5 using a small flathead screwdriver.

Plug the pump motor power into the harness, and let the pump run until the reservoir level goes down.

The coolant pumps are not intended to be run dry. Avoid having the pumps run when the reservoir level is low.

Unplug the pump power to stop it.

Add coolant solution to top up the pump reservoir.

Plug the pump in again to repeat the fill-pump cycle.

The pumps are most effective at driving air out of the system when the reservoir is near full before starting, so make sure to top up between each fill-pump cycle. If you find the pump is still unable to fill the circuit, cycling the pump power on and off a few times is effective at dislodging any air clogging the circuit.

After about three cycles, there should be enough coolant in the circuit to achieve “steady state” flow. At this point, you no longer need to cycle the pump on and off - simply keep refilling the reservoir as necessary as the air continues to flush out of the circuit. Decrease the pump motor speed dials to 3.

Continue filling until no more large bubbles are visible.

Flush Out Any Remaining Bubbles

Bring the speed of the pumps down to 1. The flow should become laminar and bubble-free. Make sure the pump is as full as possible with coolant solution.

Increase pump speed to 2 on one pump only. Watch for bubbles coming out of the printer (the left tube coming out of the printer) and out of the radiator (radiator-to-pump connection). Once there are no more bubbles moving through the system, increase the other pump speed to 2. Top up the pump reservoir with coolant solution if needed.

Repeat this process, increasing pump speed on one pump at a time, until both pumps have reached 4 (with both pumps at 5, you will not have a smooth flow and bubbles will become entrained in the flow out of the pump.).

With both pumps still at 4, leave the cooling system running for about 10-15 min to finish flushing any remaining bubbles.

Return the pumps to 1 for normal operation.

Pump speed set to 1 for normal operation

Check the Coolant Reservoir

Check the reservoir level on a regular basis. If the coolant circuit lines at the back of the pump have bubbles running through them, please refill the reservoir at the back and flush the bubbles using the above procedure. The GIF below shows what it may look like when the coolant circuit is lacking coolant.

A coolant circuit that needs to be topped up