First off, if this is a residential steam boiler, in a typical home, that pressure is dangerous. The relief on a residential steam boiler shouldn't exceed 15 psi. That 30 psi relief has turned that boiler into a bomb.
Originally posted by heatseeker
The smoke test showed about a 1,& the draft test showed 6.It is direct vent into a chimney,the steam presure is 18 but keeps trying to rise to around 20 psi,the pressure relief valve is rated 30 psi. The boiler runs fine but you still get that puff of smoke about every third fire up.