Combi Boiler Safety Rules
Follow these rules to keep your combi boiler safe.
Water gauges – Keep all connections and valves clear. Test by blowing down the water glass and water column regularly. Gauge cocks or tri-cocks should also be blown regularly.
Safety valves – The combi boiler safety valve is the most important valve on the boiler. Safety valves prevent dangerous over pressurization of the boiler. Safety valves are installed in case there is failure of pressure controls or other devices designed to control the firing rate.
All safety valves should be kept free of debris by testing the safety valve regularly. This should be done when the steam pressure is at approximately 75 percent of the safety-valve set pressure. Safety and safety-relief valves on low-pressure boilers should be tested at least quarterly, this is in accordance with the National Board Inspection
Code.
For commercial boiler rooms also note the following boiler guidance.
Firing – Aside from the standpoint of economy, maintain the combi boiler fire as uniformly as possible to avoid an excessive rate of combustion, undesirable variations in temperature and possible explosions. The destructive force in a boiler explosion is caused by the instant release of energy stored in the water as heat.
Boiler-room requirement – A current proper engineer’s license and log shall be posted in the combi boiler room. It is the responsibility of the owner and the engineer to make sure the boiler is inspected annually.
Starting fires in a boiler – Before starting fires in a cold boiler or restarting a fire that may have been accidentally extinguished, the entire fireside of the boiler must be thoroughly ventilated (purged) with the dampers open to remove unburned gases before attempting to relight the fire. Attempting to start a fire in a boiler with unburned gases is the most common cause of boiler furnace explosions.
Hot-water systems – These systems are equipped with expansion tanks for the expansion and contraction of the water as the temperature varies.
Firing cycle, power burners – The burner will start when the aquastat or pressuretrol calls for heat. The breeching damper will open and the draft fan will purge the combustion chamber. The main gas or oil valve will be energized when the pilot or ignition is proved.
Repairs – Any excessive overheating or burning, and any major repairs, must be reported to your boiler inspector.