How to change the CO2 bottle for a G3 HydroTap Command Centre

Relates to: Filtration and CO2

If your sparkling water is coming out of the tap flat it might be time to change your Co2 cylinder. First, check the regulator pressure gauge located on the cylinder to see where the needle is pointing. If it is down towards the left in the yellow zone, adjust the knob on the top of the bottle. If the needle doesn’t go back to the green zone then the cylinder will need to be changed. 

Zenith part number 91295NZ (2 x cylinders of 1000 grams of Co2). Note – safety glasses and gloves should be worn and have a towel handy. Take care when fitting or removing the regulator from the bottle. 

If you are unsure about changing a Co2 cylinder, a qualified Zenith service technician would be happy to assist. Call 0800 558 055 to schedule an appointment.

Step 1: First you will need to turn the Co2 cylinder regulator off. Do this by twisting the knob anti-clockwise until it screws up and away from the bottles.



Step 2: It’s important to start the Co2 purge to relieve any pressure in the Co2 line. On the on-screen menu, press the [MENU Λ or MENU V] button until [Co2 Purge OFF] is displayed. Press [Adjust Λ] to start the Co2 purge, [Co2 Purge ON] will be displayed. The gas flow will slow and then stop. Press [Adjust V] to stop the Co2 purge.

Step 3: Remove the bottle from the cupboard and disconnect the regulator by unscrewing it from the bottle. The braided hose can be left attached to the regulator. 

Step 4: The regulator and hose assembly needs to be fitted to the new gas bottle. Do this by screwing the new regulator in place. Be aware some Co2 may be discharged from the cylinder as the regulator is attached so make sure the bottle is upright at all times

Step 5: Slot the bottle back into place in an upright position securing it with the fixing strap

Step 6: Turn the Co2 cylinder regulator on by twisting the knob slowly clockwise. Watch the needle on the gauge carefully and keep twisting the knob until the gauge indicates 3.0-bar in the Green zone on the dial 

Step 7: It’s important at this stage to check for gas leaks so take a soapy sponge and allow some soap suds to fall on the regulator fitting and hose. Watch carefully for any movement or an increase in bubbles – this may indicate a leak. If you spot a leak, twist the knob back in an anti-clockwise direction (turning the regulator off). 



Go back to Step 4 and repeat. Wipe off suds and repeat the checking process. Only proceed to Step 8 when no leaks are detected. If further assistance is required please call Zenith Customer Care on 0800 558 055. (image showing suds on regulator)


Step 8: Next you need to purge the gas lines to ensure the new Co2 cylinder will work efficiently. The LED screen should still be showing the Co2 Purge screen from Step 2. Press [Adjust Λ] to start the Co2 purge, [Co2 Purge ON] will be displayed.  This will push Co2 and water through the HydroTap’s system. 



Step 9: Let the Co2 flow until the water has finished and only Co2 is being dispensed from the tap. Leave the Co2 flowing for 5-10 seconds longer, then press [Adjust V] to stop the Co2 purge. 



Step 10: Press the [MENU Λ] button and your unit will return to [Normal Operation] in approximately 10 seconds.



It’s a good idea to dispense some sparkling water from the tap and perform a taste test. There may be a small burst of gas pressure when you perform this task but if you let the levers go then press again, the unit should work normally. 

Step 11: Residential HydroTap cylinders are non-refillable but can be recycled at most council recycling facility. Please do not place in council bin but dispose of thoughtfully. If a Zenith technician changes your cylinders, they will remove the old cylinder and recycle it for you.

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