Error 20

Error 20 is Lamp failed to start.

Check the 12V and 24V. The manual also mentions checking water temp and pressure. In my experience, it may also be low resistivity in the water. The easiest way to rule that out is to drain the coolant, replace the DI filter, and refill with distilled or sterile water.

Thanks for your reply,

I have done all what you told me still same error( i have changed the lamp, the water with sterile distilled water) and cheked the electronic part. Dont know what to do anymore.