If you are using the mainboard air assist port to control your pump and it is not working, 

1. Access "Vendor param" on RDWorks. (Password: rd8888)
2. Click "Other".
3. Tick the box before "Enable blower".
4. Access user parameters.
5. Click "Other" to see the dropdown list.
6. Set "Blow type" to "Lase on blow".                                                               
7. Check if the pump is working.
8. If not, measure the voltage between the 24V port and the "wind" or ("Aux-air") port on the mainboard.

• This reading varies when the engraver starts and stops working. If you keep getting the same reading whether the engraving is working or not, then the mainboard is faulty. Replace it with a new, identical one.