As another winter approaches, the boiler annuals and service calls come rolling in.  
I've received many e-mails asking for boiler info and maintenance routines.

"A boiler is an encased vessel that provides a means for combustion heat to be transferred into water until it becomes heated water or a steam. The steam or hot water is then usable for transferring the heat to a process. When water is boiled into steam its volume increases about 1,600 times, producing a force that is almost as explosive as gun powder. This is very good and efficient means for transferring heat for a process but it can also be extremely dangerous."

Although they all pretty much work on the same principles, special attention needs to be added in checking out each individual boiler.  The wrong valve opened or closed can be a disaster and a safety hazard.

The two most general types of boilers are hot water and steam boilers. Most small and large commercial buildings, manufacturers and business use hot water boilers. Water is heated to dispersing temperatures, typically 140-180ºF, and usually returned about 20ºF lower. These systems are called "closed loop", with minimal fresh water make-up.  Hot water boilers are preferred because they normally do not need operators or major water chemistry.   Since they operate at lower temperatures, hot water boilers can operate at higher fuel conversion efficiencies than steam boilers.

Steam boilers are used in many different applications, their one purpose: to use water and transform it into steam by   heat. Some boilers heat the steam even hotter than the boiling point temperature. This is referred to as superheated steam.

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The number ONE concern and reason for boiler maintenance is "SAFETY".
Below is a article from " The Pressure News" . This Newsletter is a publication of Alberta Boilers Safety Association (ABSA).

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A couple vital parts :

LOW WATER FUEL CUT OFF shuts off fuel to the burner in the event of a low water condition in the boiler. The low water fuel cut off is located 2" to 6" below the boiler water level. Low water fuel cut offs operate using an electric probe or a float sensor, if the sensor indicates a low water condition a contact to the main burner control circuit opens and shuts down the main gas.   Low water fuel cut offs should be tested monthly or more often depending on usage or requirements.

If a low water condition is not properly sensed and the gas train does not shut down, the boiler can overheat . Overheated boilers will be permanently damaged. If the safety valve has not been serviced properly and does not relieve the pressure adequately, the boiler may explode and result in injury  or worse.

SAFETY VALVES are the most important devices on a boiler. they open to relieve pressure that rises above maximum boiler operating pressure.  

No valve can be installed between the boiler and the safety valve. 

Safety valve capacity and blowout information is listed on the name/data plate on the safety valve.  Safety valves that are spring loaded are the most common safety valves. A spring exerts pressure on the valve against the valve seat to keep the valve closed. When pressure inside the boiler exceeds the set popping pressure, the pressure forces the valve open to release the pressure.  Most state and federal code require the outlet to be piped @ 8" from the floor.

Maintenance Inspections

Maintenance is needed for many reasons. 
A few primary reasons for the need of a preventative maintenance program are

(1) Safety

(2) Major boiler repairs or replacement costs.

(3) Reduced downtime due to unexpected breakdowns.

(4) Reduced fuel costs by improving efficiencies.

(5) Safety - ( I know, but it's important )

All manufacturers of boilers supply operating manuals with their equipment. Unfortunately, most boilers do not have manuals and operating instructions available.  It is the responsibility of the owner or person in charge to obtain these publications and see that they are posted, understood and followed, in the boiler room.

Summer Maintenance

	Drain and flush the boiler, open all handholes and manholes, clean and remove soot and scale from the firewalls. check the boiler for damage and corrosion.
	Start a   boiler water treatment program to reduce scale buildup and corrosion.
	Install new gaskets, replace all hand hole and manhole covers, refill boiler and perform a hydrostatic test, if required.
	Disassemble the low water cutoff and water feeding devices, clean and reassemble them.
	Clean all gas burning equipment and adjust  controls. Verify operation of all operating and limit controls, interlocks, shutoffs and gauges. leak test all fuel safety shutoff valves.
	Lubricate all mechanical equipment such as fans and pumps, verify motor rotation and operation. Remove pilot assembly, clean and adjust.
	Start a maintaining a boiler log.
	Check all boiler piping for leaks and missing insulation.
	Ensure boiler certification is current.

Winter Maintenance

	Verify boiler room is clean.
	Check that all ventilation and combustion air openings and louvers are clean and free of debris.
	Verify boiler water level.
	Check that all stack dampers are open.
	Examine the boiler furnace for foreign material.
	Check the furnace and flue passes for fuel accumulation.
	Check flame color and height.  Remove pilot assembly, clean and adjust.

	Check that boiler cuts-in and cuts-out at the correct pressures and temperatures. Test high and low fire proving switches.
	Test the safety relief valve (s) manually by means of the hand lifting lever when boiler pressure is 1/2 of valve set pressure.
	Check for evidence of soot, smoke and condition of flame.
	Test flame detection devices.
	Test low water fuel cut-off.

Note:
For a boiler to effectively transfer heat, the combustion chamber must be kept clean of soot build-up. This soot build-up arises as a by-product of the normal function of the combustion chamber. But soot also acts as a natural insulator. Every 1/16" of soot build-up reduces boiler efficiency by 4.5%.

Above all remember " SAFETY"

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