error ( DCD canister is empty)

You probably need to reset the DCD counter.  

Every time you put in a new canister, reset the counter.  It will then count down the approximate number of shots left in the cannister.  When it reaches zero, the can is APPROXIMATELY empty.  

how i can  reset the counter? can you give me steps ? thanks

On the main screen, there should be a DCd section which will have the counter and there should be a reset button which would look like a circular Arrow. Just press and hold that and it should reset the count up to I don't know 10 or 15,000 depending on what your spray settings are.

On the older mini Gentlelase or mini gentle yag, you just press and hold the actual counter display.

The user manual might have better instructions.

On the main screen, there should be a DCd section which will have the counter and there should be a reset button which would look like a circular Arrow. Just press and hold that and it should reset the count up to I don't know 10 or 15,000 depending on what your spray settings are.

On the older mini Gentlelase or mini gentle yag, you just press and hold the actual counter display.

The user manual might have better instructions.

Are you using the candela supplied white cans? There are issues all the time with these cans, but Candela will not admit to any wrondoing.

If it is a machine fault, then its could be the potentimoter on the pcb at the cryogen heater

here button only for reset pulse counter 

 Laserway

yes i use white cans but i tried with black cans and i had the same problem 

Assuming that it is a machine malfunction, you will have to check if the correct voltage is going from the dcd pcb to the main cpu. Put a voltmeter between test points 52 (positive) and 47 (negative). When the can is empty, it will send a voltage  (usually 11.5v+) to the cpu. When there is gas in the can, the voltage would be 7.75V plus or minus 0.5v. put on a fresh black can, see what the voltage is. Afjust the blue vriable potentinomoter on th edcd pcb to the correct voltage (7.75) and your system may run properly again

Bottom right corner. Your counter is at '0'.

The button with the circular arrow is the reset button. 

 I had voltage 20v when there gas in can and when the can is empty