
This can ignite a gas leak, resulting in fire or explosion. Figure 5.1: Gas Connection to Boiler 8. Disconnect the boiler and its individual shut-off valve from the gas supply piping system during any pressure testing of that system at test pressure in excess of 1/2 psig (3.5 kPa). CAUTION Do not subject the gas valve to more than 1/2 psi (3.5 kPa) pressure. Doing so may damage the valve. Isolate the boiler from the gas supply piping system by closing its individual service valve during any pres