{valve,boiler}={(TransferFunctionModel[(1.2/((0.8s+1))), ]),(TransferFunctionModel[((0.1(1-2s))/(s(5s+1))), ])};

pid2dof=PIDTune[SystemsModelSeriesConnect[valve,boiler],"PID","PIDData",PIDFeedforward->0.5];

level=OutputResponse[pid2dof["ReferenceOutput"],5UnitStep[t],{t,0,65}];

Plot[{level,5UnitStep[t]},{t,0,65},PlotRange->All]