From time to time queries will be asked of a Service or Technical nature. We have listed the most commonly asked questions with responses. Forms are provided at the end of this page if you do not find an answer or solution to your query. You may also use the form if you have a query for a currently owned ARUN instrument. We will endeavour to give you answers and support you in finding solutions.

Service FAQs

Where can I find my the instrument serial number?

The serial number can be found either on the back of the instrument or in the analytical software.

In the analytical software:

Click “HELP” then click “ABOUT”. Here you will find information about who the instrument was sold to, the order number and serial number.

How can I identify the instrument model?

In the analytical software, click “HELP” then click “ABOUT”.

Why is the instrument screen blue/black?

    This suggests that the monitor is not receiving a signal. Check that the monitor is connected and also check that the PC is “ON”.

Why are there three white rings on the burn spots?

White burns mean poor argon/sample preparation.

  • Check a freshly prepared setting up sample (see section 5 of the User Guide)
  • Check the argon is of the correct grade and that the supply is on (see section 3.1 of the User Guide)
  • Check that the argon exhaust is not blocked
  • Make sure the instrument has had time to flush through
    (see section 3.10 in the ARTUS 8 Guide, 3.8 in the Neo and Save Junior Guide)

Small Milk White Burns - Low Argon Pressure


The argon inlet may be blocked or the supply tank has insufficient pressure. It is advised to check the pipes for leaks and the pressure on the argon tank.

Large Burn Zone with Little or no Soot - Low Argon Purity

The purity of the Argon being supplied is insufficient and therefore having a detrimental impact on the quality of the burns. ARUN  Technology recommends using liquid argon as it offers the highest purity available.

Argon contained in canisters (typically used for welding) has a purity rating of 99.995%. Liquid argon has more than a 99.999% purity rating. The photos compare the burns for low purity argon highlighted by the red circle and the remaining burns achieved with liquid argon. Note that the correct burns have distinct areas of soot and vaporisation whereas the incorrect burn shows a large vaporisation area with little soot.

Why is there no bubbling sound?

  1. Check the argon is on and the supply is OK.
  2. Check the exhaust is not blocked (see section 4 of the User Guide)

Why is the argon not flowing?

  1. Check the argon is “ON” and the supply is OK
  2. Check the exhaust is not blocked (see section 4 of the User Guide)

Why is my analysis incorrect?

  1. Check the burns are good
  2. Check the instrument is stabilised and that the profile is good (see section 3 of the User Guide)
  3. Check user maintenance has been performed (see section 4.1 of the User Guide)
  4. Check the metal has been sampled and prepared correctly (see section 5 of the User Guide)
  5. Standardise the program being used (see section 4 of the A Plus Software Guide)

Why won’t my instrument start?

    The ARTUS 8 and MERLIN 4 have both a Source and Power button that needs to be pressed for the machine to turn on. The “ON” state is indicated by a blue light when the toggle button is locked in the down position.

Why won’t my instrument burn?

  1. Check that the source is switched “ON”
  2. Restart the instrument and PC to ensure connection has been made

How and where can I replace my setting up samples?

Before the sample is too thin or beyond its useful life to use for the re-standardisation procedure; a replacement should be ordered.

Contact servicesupport@aruntechnology.com.

What do I do if my Polyspek NEO or Polyspek Junior has a hardware issue?

If the instrument has a hardware issue, it must be sent back to ARUN for inspection and service. E-mail servicesupport@aruntechnology.com for more information.

The argon inlet pipe will not fit

Either the pipe is the wrong size or it was cut poorly by the end user.

Both the ARTUS 8 and MERLIN 4 are equipped with 6mm pipe inlets for use with either PTFE or copper pipes.

Ensure the pipe is the correct size or use the appropriate adaptors. Specialised PTFE tube cutters are available to assist in creating a clean, perpendicular cut.

LOW PRESSURE WARNING - Argon Inlet is Blocked

The PTFE and Copper pipe may have been bent preventing the argon from flowing. Remove the obstruction and check the pipe for damage. Replace the pipe if necessary.

LOW PRESSURE WARNING - The filter is not connected properly

Without the filter attached, the system will not be able to build pressure because the argon can freely escape. The filter system is installed by attaching the inlet (located on the front, left-hand side of the unit) into the spark stand. This is achieved by unscrewing the screws located on top of the plate, and then removing it. This allows the housing to be removed and the pipe connector to be clearly visible.

LOW PRESSURE WARNING - The filter does not contain water

To operate correctly, the filter located on the left-hand side of the exhaust system needs to be half-full of water.

LOW PRESSURE WARNING - Sample is incorrectly prepared

To be tested, the sample needs to have a smooth flat surface. Harder materials can be prepared with a linisher with 40 or 60 grit sandpaper. Softer materials can be cut on a lathe. Fine grit sandpaper or polishers should be avoided. A reflective surface will diminish the machines’ performance.

INCONSISTENT READINGS - Contamination of sample

The machine operator must always be aware to minimise sample contamination. Typical contaminating actions include:

  • The sample surface being touched by the Operator
  • Linisher being used for different materials
  • Not cleaning the electrode
  • Placing sample over electrode aperture (instead of sliding)
  • Using the same electrode brush with different base materials
  • Oxidation

Inconsistent Readings - Incorrect Electrode Height

The electrode height can be adjusted by loosening the electrode with an Allen-Key, setting the distance with the provided tool and then tightening the bolt.


The filter system will get blocked if it is not cleaned regularly. This will cause the argon and soot to escape through the electrode aperture.

The blue exhaust pipe can be cleaned by passing water through it. New filters can be purchased from ARUN Technology. Email servicesupport@aruntechnology.com to place an order.

Why is the burn sequence louder than normal?

The reason can be an incomplete seal.

This occurs frequently with thin; poorly prepared samples. The noise is a result of the arc not being properly covered. Better surface preparation will improve the seal. However, variation in material properties will cause some samples to be louder than others.

Why am I unable to standardise or pixel check?

This could be that the setting up samples (SUS) are too thin due to continuous usage.

Setting up samples can be purchased from ARUN  Technology.

Email: servicesupport@aruntechnology.com.

Application FAQs

Can grey, lamellar, and nodular elements be analysed?

Yes. They must be chill cast down to white form, before being analysed. When these elements are chill cast, they are being made graphite-free. An analytical reading is then possible.

What is chill cast?

Iron-carbon alloy with low graphitization factor so that chill occurs forming a graphite-free structure. The carbon is present bonded in the form of iron carbide, which is why the break surface of the material appears whitish instead of grey. The carbides of the unalloyed types are ledeburite and cementite (Fe 3 C) or austenite with eutectoid decay (perlite).

How low a reading is obtainable on the CuNiZn curve as it relates to melted scrap that can have a nickel reading between 0.5% to 35%?

ARUN Technology has data for high and low CuNiZn readings in relation to nickel. These results are dependent on the concentration of metals in the sample.

Is it possible to setup a command to stop the instrument from working if the program has not been standardised?

It is not possible to setup a command to stop the instrument working if the program has not been standardised. Standardisation should be performed once a week. This should ideally be done at the beginning of each week.

Service Request Form

Only fill the form if you agree that ARUN stores this information.

To learn more about ARUN’s privacy policy, click here.

Service & Technical Queries

Only fill the form if you agree that ARUN stores this information.

To learn more about ARUN’s privacy policy, click here.