These maintenance items should be done once a year by an experienced boiler radiant heat contractor between heating seasons (August to October): 

• Inspect and clean fireside surfaces.
• Inspect all burner refractory material.
• Inspect all manhole gaskets for leaks.
• Inspect and test all system valves.
• Inspect and test all safety valves.
• Clean and rebuild low water cut-off.
• Recalibrate all operating controls.
• Overhaul feed water pumps.
• Clean condensate receiver.
• Clean the combustion chamber, fins and tubes.
• Inspect electrical terminals.
• Switch boiler automation to summer mode.
• Check fuel oil levels.
• Check combustion parameters.
• Clean and inspect chimneys.
• Clean and tune boiler and components. 

These items should be addressed by the building's maintenance staff on a continual basis, or as often as indicated below:

• Check and maintain proper oil level in compressor lube tank (daily). Use SAE 20/30 oil.
• Clean oil filters at least twice a month:
• Shut-off power to pump motor.
• Close shut-off valve.
• Pull out filter. Clean filter and re-insert into housing.
• Place strainer cap into proper position, restart pump motor, and check vacuum.
• Vacuum reading must be high; if not, check seal on cap. If reading is high, then open oil valve.
• Check oil pressure reading at the burners.
• Keep sight glasses clean. This allows for a clear view of the burner flame and any carbon build-up on the boiler's combustion chamber (as needed).
• Keep air filters clean. A clogged air filter can lead to poor air/oil mixture and carbon build-up (as needed).
• Check oil circulation temperature at sidearm pre-heaters. Inlet temperature should be 110° F to 120° F, and outlet temperature should be 140° F to 150° F for No. 6 oil (daily).
• Flush drain low water cut-offs/sidearm oil pre-heater (twice a week).
• Flush drain low water cut-offs while burner is on and a flame is present in the boiler's combustion chamber. When the unit is flushed, the flame should turn off. Allow the burner to start before checking other low water cut-offs.
• Flush down water-line heater, shut off lower isolation valve, open drain valve to flush unit, shut drain off valve, and reopen isolation valve. 
• Conduct boiler bottom blowdown to clear sludge and sediment, control high water, and control chemical treatment concentrations (monthly or as needed).
• Monitor the make-up water being added to the boiler and/or the boiler feed unit. Since the system operates via closed loop, an excess amount of fresh (untreated, oxygenated) water supply is detrimental to boiler components and is often a sign of a leak in the system. 
• Monitor smoke alarm on a weekly basis.
• Wipe light source and receiver.
• Smoke alarm unit should not be set at its highest point.
• Unit should be set in accordance with NYC Buildings Department standards.
• Maintain a rigorous boiler chemical feedwater treatment program. 
• Maintain a boiler room log to record any problems and routine maintenance.
• Check combustion, inspect burner controls, and inspect burner operation.
• Conduct trap inspection program with replacement of trap elements in apartment units and steam traps within the cellar.
• Conduct pipe inspection program to ensure all pipes are pitched in the direction of steam source (one-pipe steam systems) or condensate drainage (two-pipe systems).