An HVAC Checklist to Simplify Maintenance
Commercial HVAC systems are major investments and regular inspections are vital to the long-term life of these complex systems. A properly installed and maintained system keeps the workspace comfortable and protects equipment from temperature and humidity swings. A break-down can cost a business dearly.
Using a detailed checklist and keeping up-to-date records gives contractors, building owners, property managers and employees confidence that they can rely on their HVAC system to hum efficiently and effectively throughout cold winter nights and sweltering summer days.
Modine Manufacturing Company has released a commercial maintenance checklist and inspection form to help contractors keep the heat on this winter. The form covers general maintenance, gas supply, gas controls, air movers, condensate removal and disposal systems, and thermostats, as well as start-up tips and a form for record keeping.
To keep the heat on during this winter’s cold weather, keep the following tips in mind.
GENERAL MAINTENANCE
Check equipment for any physical damage that may have occurred over the summer. This should include damage to sheet metal, fans and air movers, wiring, gas pipes, vent systems and equipment supports. Look for cleanliness of heat exchanger and burners.
Check to make certain the vent system has not been compromised and is in the proper working order. Be vigilant for obstructions that may be blocking the air inlet or discharge paths of the heat exchanger.
GAS SUPPLY
Check to make sure that gas mains are turned on and be sure inlet pressure and manifold gas pressure to heating equipment is properly set. Check gas regulators to be certain regulator vents are not plugged.
If propane is being used, check main regulator on tanks for proper pressure settings and check for damage to regulators. Be sure propane tanks are the proper size with the appropriate liquid propane levels.
GAS CONTROLS
Inspect all gas connections for good tight fits, which includes pipe connections to the equipment and pilot tubing connections at the gas valve and at the pilot burner. In addition, inspect the main burner gas orifices to make sure they are not blocked with spider webs as well as the pilot orifice for obstructions if pilot cannot be lit or will not stay lit.
After visual and physical inspection of the gas connection, turn on the gas and check for gas leaks using a water/soap solution. Do not check for gas leaks with an open flame. Check electrical connections to gas valve. Check components such as the thermocouple, pilots, flame sensors, and ignition cables for cleanliness and tightness of connections.
AIR MOVERS
Lubricate motor bearings if they are not the permanently lubricated type. With the power turned off, check to see that the motor shaft turns freely and does not bind by rotating the fan or blower wheel by hand. Inspect the fan or blower wheel to make sure they are not damaged or binding.
Check to make certain fan is not loose on motor shaft. If blower units are used, make certain the blower and motor pulleys are secure. On blower units, check for proper belt tension and also look for signs of belt wear. Check power connections to motor to ensure they are secure and have not vibrated loose over the past heating seasons.
It’s important to note that equipment using belt drives should have the belt tension checked on initial start-up. Periodic inspection should be made during the heating season to ensure continued proper operation.
CONDENSATE REMOVAL AND DISPOSAL SYSTEMS
If the units are gas-fired condensing units, check the following items:
• Make sure the condensate lines are clear of obstructions and free flowing.
• Assure the condensate drain line “P” trap has been primed and filled with water.
• Check the condensate overflow switch to make sure it is working properly.
• If the unit(s) has been provided with a condensate removal pump, check to make sure the pump is working properly and has not been damaged.
THERMOSTATS
Check for general cleanliness and inspect the wiring to and from the thermostat, and check the thermostat for proper temperature setting.
GAS BURNERS
Inspect the burner for general cleanliness. If the burner requires cleaning, clean with a stiff brush (not a wire brush). Inspect inside of burner tubes as much as possible. During the summer months it is not uncommon to find that spiders or mice have taken up residence inside the burner. Inspect burner for proper location making sure that it is properly aligned and securely fastened.
VENT SYSTEMS
Check to make certain vent system is clear and free of any obstructions. Be sure all connections are secure and tight. Inspect the entire vent system for signs of corrosion, damage, and all potential issues that could lead to vent products entering the heated space or vent products recirculating into combustion air. Clean the vent pipe and clean out the cap, if necessary.
START-UP
For standing pilot systems, turn off the power to the unit and turn on the gas to the unit. Then, turn the gas valve control knob to the “pilot” position. With the gas valve control knob in the “pilot” position, manually depress the knob and light the pilot. After 30 seconds, release the control knob and assure the pilot remains lit. Next, turn the gas valve control knob to the “on” position. Restore power to the unit and cycle the unit via the unit thermostat to assure it operates correctly.
For intermittent pilot systems, turn off the power to the unit and remove the wire lead from the main valve terminal of the gas valve and protect the wire to prevent shorting. Then turn the gas valve control knob to the “on” position and turn on the gas to the unit to restore power. Cycle the unit via the thermostat and observe if a pilot flame has been established (and that it remains on). Next, turn the thermostat down and observe if the pilot flame has been extinguished. After checking the electronic ignition pilot system functionality, turn off the power to the unit and reconnect the wire lead to the main valve terminal of the gas valve. Restore power and again cycle the unit via the thermostat and observe that both pilot and main burner ignition occurs. After checking, reset the thermostat to the desired room temperature.
For direct-spark system, turn off the power and main gas to the unit. Remove the wire lead from the main valve terminal of the gas valve and protect the wire to prevent shorting. Then turn the gas valve control knob to the “on” position. Restore power to the unit, but do not restore the main gas. Cycle the unit via the thermostat and observe if the direct-ignition device is energized. (If the unit has a hot surface igniter a yellowish glow will appear in a few seconds. If the unit has a spark ignition type igniter, a sparking sound will be heard, and a blue spark may be observed and the igniter). After proving the igniter function, restore the main gas to the unit and again cycle the unit via the thermostat and observe that both the main burner ignition system is functioning and that main burner ignition occurs. After checking, reset the thermostat to the desired room temperature.
On all units, observe the burner flame to insure that it is burning clean and not wavering, rolling out, lifting or fluctuating. If an abnormal flame is observed, check the equipment installation and service manual or report it to your service technician.
RECORD KEEPING
It is recommended that a record be kept of the date the heating equipment was last checked and serviced. Follow all instructions and cautions in the installation, operation, and service manuals originally provided with the equipment.
Click here to view the entire checklist.
