We have a low pressure steam boiler. It operates at ~10-15psi and creates steam at temperatures of 80-90 C. It is hot and dangerous, and it is a very important piece of equipment. It heats everything on the brewhouse.
Verify the Sight Glass has water in it. Operating a boiler without water in it is very damaging. Even if the water is low, the first thing the boiler should do before firing is to pump water from the expansion tank to the boiler. Stay until this happens if there is not enough water and do not let the boiler start if the sight glass doesn't fill.
Verify the Expansion Tank has water in it, and that all valves inline are open for it to get more water as needed. Condensation is returned to this expansion tank during brewing, so it has warm water in it. (You never want to put cold water into a hot boiler because it will shock it.) If the boiler needs more water it will request it of the expansion tank and when the level in the tank drops below a certain point, it will request some cold water that will be tempered by the hot water already inside. It is important that there be water in there to start so that the pump under it is never run when dry.
**Do not start boiler unless all vessels have water in them.**
Turn on red power switch. !(https://cloud.githubusercontent.com/assets/464725/8602757/e9d19e20-2628-11e5-835f-58cf6f641aff.png)
Press Reset button on Honeywell control box. !(https://cloud.githubusercontent.com/assets/464725/8602759/e9d365c0-2628-11e5-9839-ae4ab07028c6.png)
The display on the Burner Control box should change to "INITIATING", "PURGE", etc. Verify that the heater blower starts.
After 30 minutes, verify that the pressure gauge reads 10psi or more and, if so, the boiler is ready to use
You should never need to open or close the big round header valve at the top of the boiler. This should remain open. However, if you are not getting steam and the boiler is on, this would be the first thing to troubleshoot.