flow into the bore 269 in single manifold embodiments l fittings or even straight fittings rather than t fittings can be used in constructing the pressure and vacuum relief valves fig2 and 21 illustrate the components of fig1 19 assembled into a valve manifold assembly 280 the assembly includes a pair of manifold assemblies 225 l 225 r the left manifold assembly 225 l is substantially as shown in fig1 while the right manifold assembly 225 r is another unit of the same assembly rotated 180 u00b0 about an axis extending generally out of the page the first manifold connector 209 l of the left manifold is coupled by the t fitting 241 of the pressure relief valve 240 to the second manifold connector 210 r of the right manifold because of the 180 u00b0 rotation of the right manifold assembly the second manifold connector provides airflow communication between the first manifold chamber 207 in fig1 of the left manifold assembly 225 l and the second manifold chamber 208 in fig1 of the right manifold assembly 225 r thus the u201c left u201d manifold chambers are connected together into one large pressure chamber spanning both manifold assemblies similarly the second manifold.