Look around and see if there are obvious dangers. Take a mental picture of the layout of the room in case of a malfunction. An open boiler pressure relief valve could quickly fill the room with steam, meaning zero visibility. In addition, steam displaces oxygen which could lead to disorientation or even death.
Refrigerant Dangers When some refrigerants burn, they produce a hazardous gas called phosgene. The International Mechanical Code requires direct vented combustion air for boilers inside a mechanical room with an air conditioner or chiller.
Exit Doors Make a mental note of the location of all exits in case you need a quick retreat.
Emergency Door Switch The emergency door switch is part of the ASME CSD1 code many municipalities follow and is a great idea. It is a switch located at every exit from the boiler room and will shut off the power to all the boilers when pushed. Some are attached to signal lights and audible alarms and will alert you if they are pushed.
Open The Doors When I enter a boiler room, I like to open the doors to the outside until I am sure there are no toxic gases or fuel leaks.
Smell? When combustion appliances are not venting or firing correctly, there will be a sour smell from the flue gases in the boiler room or basement. It is difficult to describe but will feel like it burns your nose and eyes. You also want to investigate any odors like natural gas or propane in the room.
Boiler Room Temperature Extremely hot or cool boiler room temperatures could indicate a malfunction. See if you can identify the cause of the excessive temperatures. In one boiler room, I was greeted with a wall of heat as I entered and found the flames would roll out the rear of the boiler on an atmospheric burner. On another project, the motorized combustion air dampers were frozen open causing the boiler room temperature to drop very low.
Negative conditions in the boiler room? If the boiler room goes into a negative condition, this causes the flue gases not to draft properly. It does not take much, only – 3/100" W.C., to pull the flame from the burner. This is called back drafting and can produce toxic gases. Look for rust atop the boiler or water heater under the draft diverters. The rust is usually an indicator of negative conditions. Verify the proper draft on the boiler and water heater using a draft gauge and test for carbon monoxide with a CO detector. It is a good idea to test for carbon monoxide around the water heaters as well as the boilers.
Flame rollout? Flame rollout, as indicated by the discoloration on the boiler jacket, shows flames and hot flue gases are not traveling the path the equipment manufacturer wanted. If the fire is rolling out, it is a safe bet carbon monoxide, or other toxic gases are being produced. The cause of the flame rollout should be investigated.
CO Detector Is the room safe? Carbon Monoxide detectors should be used to verify CO is not present in the room. You could use either the ones with an external sensing tube or the personal ones that clip on a belt. The plug-in types found in home supply companies should not be used as a service tool carried from job to job as they are designed to be left in the room. Some facilities also use combustible gas detectors.
Combustible Gas Dangers Natural gas usually is odorless, and Mercaptan is added to be able to detect the gas. It is a good idea to have a combustible gas detector for the room.
Listen for strange noises When entering the boiler room, listen for unusual sounds warning of potential dangers. Some of the noises I listen for would be:
Water is dripping or leaking.
Electrical arcing may mean a short or bare wire.
Hissing could be steam or gas escaping.
Loud ticking may be excessive scale buildup or a low water condition in the boiler.
Banging may indicate a boiler malfunction, especially a metallic banging.
Popcorn or Rice Krispies Excessive scale or low water condition is sometimes thought to sound like either of these two items.
Excessive vibration could indicate a pump or a motor malfunction.
Loud humming could mean a bound motor or pump.
Water on the boiler room floor may indicate a leaking pipe or boiler. Try to detect the origin of the leak. Water beneath a boiler could be from either a leak or flue gas condensation. A leaking relief could indicate the pressure is excessive or the relief valve is getting weak. Did you know some old timers used horse manure to plug leaking boilers?