Continental Girbau L28STK30G Owner's Manual page 15

Gas Piping Installation (Illustration)
Gas
Valve
Gas
Supply
The dryer and it's individual shutoff valve must be disconnected from the gas supply piping system
during any pressure testing of that system at test pressures in excess of 1/2 psi (3.5 kPa).
The dryer must be isolated from the gas supply piping system by closing it's individual manual shutoff
valve during any pressure testing of the gas supply piping system at test pressures equal to or less
than 1/2 psi (3.5 kPa).
Page 15