Scuba regulators are separated into five or more components. These consist of the regulator's first and second stages, the alternate air source, a submersible pressure gauge and the low pressure inflator hose. The components all screw into ports on the regulator's first stage. Other items can also be attached, including dry suit inflator hoses and transducers. Care should be taken as to which ports on the first stage the components are attached to, and whether they should be attached to a high pressure or low pressure port. The unit's final configuration should also be taken into account when selecting ports for the components.
Decide where to attach your hoses on the regulator's first stage. The submersible pressure gauge must be attached to the high pressure port. Using the Allen key, remove the plugs from the selected ports.
Cover each O-ring on the hose ends with a thin layer of silicone grease. This will ensure a good seal when the component is attached.
One at a time, screw the component hoses into the selected ports. Tighten them with the wrench but not too tightly, as this can damage the O-rings.
Attach the unit to a scuba tank with an appropriate valve, either a yoke or DIN. Make sure the attachment is only as tight as you can make it with your fingers.
Holding the submersible pressure gauge face down, slowly open the scuba tank valve and listen for hisses and popping sounds as it opens. Open the valve fully, then move it one-quarter turn back.
Check the submersible pressure gauge for the tank pressure. Ensure that it is taking a reading from the tank
Breathe from the demand valves on the second stage and the alternate air source, to ensure that the air is being supplied via the first stage. At the same time, check if the purge valves on the devices are working, by depressing the buttons on the front.
Turn off the tank valve and depressurise the system by pressing one of the purge valves on the second stage or alternate air source. Disengage the assembled regulator unit from the scuba tank and store the unit.
The second stage, plus the alternate air source, the low pressure inflator hose and the dry suit inflator hoses should only be attached to low pressure ports on the first stage. The submersible pressure gauge and transducer are attached to high pressure ports. When deciding on your configuration pay attention to where the hoses will go on the final, assembled scuba unit, when attached to a BCD.
Check the manufacturer's guidelines before assembly. If unsure about the assembly, contact a scuba diving technician.