At Rittenhouse we stock all replacement parts for the D30 Diaphragm Pump. This pump also goes by the name of AR 30.
If your D30 is in constant use we recommend that you rebuild the pump every 1 to 2 years. A kit is available to do just that. That way you and your business can rely on this pump.
The Lower Air Chamber, which is reference # 47 on the diagram above, has had 3 different part numbers in the last 15 years. But it is still the same part. It has also been 9910-620180, 9910-629209 and also 9910-622070. Rittenhouse is currently using 9910-622070 for that part. We used to call it an Accumulator Manifold but Hypro now calls it the Lower Air Chamber. Also, if you are ordering that part, be sure to order the 4 o-rings (9910-390060) with it because you will likely rip or damage your current o-ring when taking it apart.
Please note that the Left Hand D30 Head Assembly is marked with an 'SX' and the Right Hand D30 Head Assembly is marked with 'DX'.