AP Diving AP Rebreather Mouthpiece Instruction Manual
7
Initial Configuration
Your mouthpiece is retrofittable to all AP Diving Rebreathers. When purchased with new
convoluted hoses , it will come ready assembled for connection to the counterlung T pieces.
If fitting to your existing convoluted hoses:
1. Remove the two pozidrive screws which lock your inhale (RB07/03) and exhale hoses
(RB07/04) to your existing Mouthpiece or OCB and unscrew both hose nuts, anti-
clockwise.
2. Either lubricate, with silicone grease, the existing hose O rings in the swivel stems -
the moulding inside the nose nuts or replace the O rings with the ones provided with
the mouthpiece, O ring size:BS029 N70 (dimensions: 41.38mm OD, 37.82mm ID),
taking the opportunity to clean the O ring groove in the stem and lubricate with
silicone grease. Be careful not to scratch any surfaces.
3. Now screw your convoluted hoses onto your new RB160 AP Rebreather Mouthpiece,
ensuring the blue insert end of the mouthpiece is connected to your inhale hose
(RB07/03), i.e. the hose fitted with the blue ident rings. Tighten securely; hand-tight is
sufficient.
4. Do NOT refit the pozidrive screws; they are no longer required as the rotational inner
is separated from the male-threaded hose connections, so there is no longer any
rotational force on the hose connection when opening and closing the mouthpiece.
The opening and closing of the valve is one handed and there is no need to hold the
mouthpiece or hose nuts with the other hand, as both opening and closing involves
nothing more than a squeezing motion between thumb and forefinger.
5. Conduct a thorough positive pressure test while immersing the closed mouthpiece
and follow with a thorough negative pressure check.
PRE-DIVE INSPECTION check list
It is essential to perform a complete pre-dive inspection of your mouthpiece valve before
every dive. NEVER dive with any diving equipment that shows signs of damage, debris,
loose connections or unsatisfactory performance.
1. Carefully inspect all hose fittings to ensure they are securely connected at both ends.
Inspect along the length of each hose to ensure that the hoses are not blistered, cut,
or otherwise damaged.
2. Visually inspect the mouthpiece for any signs of external damage or debris.
3. Visually inspect the mouthpiece bite for damage or cuts and ensure it is securely
fastened to the Mouthpiece.
4. Check the rebreather’s one-way valves for back leaks.
Located within each end of the mouthpiece valve are the
one-way valves which are assembled to ensure they pass
gas the correct way around the rebreather. It is essential to
check the direction of gas flow and check the proper
operation of the one-way valves prior to each dive. The
valves could leak due to debris left over from cleaning, due
to faulty assembly, worn components or due to being frozen
open (in freezing conditions). They are the only moving parts
within the rebreather’s breathing circuit, they deserve proper
testing. This check can be easily carried out by
disconnecting the hose connectors from the T piece and
gently blowing and sucking against the connectors. The
direction of gas flow for the AP Diving rebreathers is
clockwise when looking down on the unit. i.e. you exhale over your right shoulder.