A beautifully built all-rivetted copper boiler, looks early twentieth century with deadweight safety valve (missing its weight, so I suppose more accurately a deadnoweight safety valve) and, unusually in a copper boiler, a manhole fastened by a bridge and studs. It's a single flue coal-fired job (the grate long since disappeared), so of modest steaming capacity, but what it lacks in pounds per hour it more than makes up for in vintage presence.
Just tested, thoroughly sound on hydraulic test at 160psi, our inspector has issued it with a certificate for 80psi working pressure with the advice to change the (probably pre-war) manhole door gasket before steaming.
12 inches to top of barrel
20 inches including chimney