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GAS HEATING Planned Maintenance Produced by Joe Marchese. Personal Safety. Good safety practices will prevent many injures Safety must be first on your mind at all times Always remove loose items when working around equipment with moving or rotating parts Be cautious of sharp objects.
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Personal Safety • Good safety practices will prevent many injures • Safety must be first on your mind at all times • Always remove loose items when working around equipment with moving or rotating parts • Be cautious of sharp objects
Personal Safety • Always lift with your legs and not with your back • Wear a back support belt when lifting heavy objects • When working with electrical equipment always verify that the power is off • Do not rely on a shut-off switch or disconnect being off -- always check yourself
Personal Safety • Be cautious of hot surfaces or work areas • Be cautious of any gas or oil leaks • Always check for carbon monoxide • Always follow proper safety practices when working with ladders • Be cautious of confined spaces - provide proper ventilation when required
Why Perform Planned Maintenance? • To reduce equipment failures • To keep equipment operating in a safe manner • To keep equipment performing at peak efficiencies • To maintain good indoor air quality
What is the most important concern for a service technician while performing a preventive maintenance inspection? SAFETY
Safety • Carbon monoxide poisoning is a major concern • Natural gas leaks can create a serious hazard • Fire as a result of damaged or bypassed safety controls • Lack of heat from improperly operating furnaces
Keeping Equipment at Peak Efficiency • Poor electrical connections can cause the system to work harder • Improper gas combustion will decrease the efficiency of a gas-fired furnace • Dirty filters will reduce the airflow through a system which will decrease the system’s efficiencies
Indoor Air Quality • Humidifiers that are not operating properly can lead to poor indoor air quality • Filters not maintained can lead to poor indoor air quality • Carbon monoxide leaking into a structure is a serious indoor air quality issue
How Long Should a PM Inspection Take? • Depends on: • the type of equipment • the detail in which the inspection is performed SHORT INSPECTION vs. LONG INSPECTION
What Are the Most Important Tools Used on a PM Inspection? Your hands Your eyes Your ears Your nose
First Steps • Determine the type of furnace • Barometric - standing pilot • Barometric - direct spark Ignition • Induced draft - DSI or hot surface ignition • High efficiency - sealed combustion
Maintenance Task Items • Always following the equipment manufacturer’s guidelines • Tasks can be grouped into four major categories: • Inspection • Cleaning • Lubrication • Operation checks
Maintenance Task Items • Check availability of combustion air (80% furnaces only) • Clean and inspect air system accessories such as humidifiers and electronic air cleaners • Check the condition of the electrical wiring and tightness of the terminals and connectors • Clean or replace air filters
Maintenance Task Items • Clean and inspect fan compartment • Clean and inspect the condensate drain system (90% furnaces only) • Clean and inspect the vent system • Clean and inspect burners and heat exchanger
Maintenance Task Items • Check thermostat and heat anticipator or cycle switch settings • Check sequence of operation • Check pilot/burner operation • Perform combustion tests • Check temperature rise • Check safety controls
Combustion Air • Different furnace designs will have different styles to bring combustion air into a furnace. • An 80% efficient furnace normally uses the air surrounding the furnace for its combustion air • A 90% plus furnace normally uses outside air for its combustion air
Combustion Air • When performing an inspection the location of the furnace should be examined to make sure it has a sufficient volume to provide enough combustion air • Make sure no other gas-fired appliances (such as a dryer or hot water heater) steal combustion air from the furnace
Combustion Air • Verify that the combustion air will not be contaminated by halogen compounds, such as fluoride, chloride, bromide and iodide vapor. • If installed in a laundry room, make sure the exhausted products vented by the dryer do not enter the furnace and are used for combustion air
Unconfined Space • An unconfined spaced has a volume of at least 50 cubic feet per 1000 Btus input total for all appliances located in the space • If the unconfined space is constructed unusually tight, the combustion air must come from outside air or from spaces freely communicating with the outdoors
Confined Spaces • A confined space has a volume less than 50 cubic feet per foot per 1000Btus of total input rating of all appliances installed in that space • There must be provisions for supplying combustion air; it can be ducted in from outdoors or from an unconfined space
Confined Spaces The number of openings and the size of the openings will depend on whether the air comes from the outside or from adjoining unconfined space
Combustion Air Requirements • If combustion air is brought from within the structure there must be 2 openings • Each opening must have a minimum free area of not less than 1 square inch per 1000 Btu of total input rating for all gas appliances in the space (should not be less than 100 square inches) • If construction is unusually tight, outside air must be brought in
Combustion Air Requirements • If combustion air is brought from outside the structure there must also be 2 openings, however: • If two vertical ducts are used they must have at least 1 square inch of free area per 4000 Btus of total input for all gas appliances • If two horizontal ducts are used they must have at least 1 square inch of free area per 2000 Btus of total input for all gas appliances
Combustion Air Requirements • A single opening can be used if it has a free area of 1 square inch per 3000 Btus of total input for all gas appliances • Failure to comply with these guidelines may result in a furnace starved for combustion air which could lead to the formation of carbon monoxide
Humidifiers Maintenance required: • Replace media pad • Clean mineral deposits from: • water reservoir or drain pan • float, float valve orifice, and valve seat • water solenoid valve orifice and strainer
Humidifiers Maintenance required: • Check for water overflow • On wheel-type humidifiers, an approved water treatment solvent can be applied to water reservoir • If a bypass humidifier is used, make sure the dampers are open for winter operation
Recommended Indoor Humidity Levels at Various Outdoor Temperatures
Electronic Air Cleaners Maintenance required: • Turn voltage off to unit (9,000 to 11,000 VDC supplied by cleaner’s transformer) • Remove the pre-filters and air cleaner cells • Clean inside of cabinet • Clean pre-filters with a mild soap solution
Electronic Air Cleaners Maintenance required: • Wash air cleaner cells with a solution of 3/4 cup of dishwasher detergent and hot water • Vinegar can also be used to clean cells • Soak cells in solution for 15 to 20 minutes • Rinse until all the solution is removed
Electronic Air Cleaners Maintenance required: • Inspect cells for any damage and reinstall with pre-filters • Leave system’s blower on for 30 minutes with power off to air cleaner to dry the cells thoroughly
Heat Recovery Ventilators Maintenance required: • Filters should be changed monthly and interior blower maintained on the same schedule as the furnace • Drain pans and interior of unit: • Clean interior surface and wipe the drain pans with a soft cloth and a mild cleaning solution • Check condensate drain
Heat Recovery Ventilators Maintenance required: • Heat Recovery Cores: • Remove from unit • Use warm water and a mild soap • Soak recovery core in solution for about three hours • Allow to dry before reinstalling
Electrical Connections • Turn off voltage applied to the furnace • Make a visual inspection of all wire terminals and wires • Check for discoloration • Check for frayed or damaged insulation • Check for any loose connections and retighten all accessible screw terminals if needed • Check fuse holders for tightness, if applicable
Air Filters Maintenance required: • Can be either cleaned or replaced, depending on type • A clogged or dirty air filter will result in the system going off on its high temperature safety limit, resulting in poor heating of the conditioned space • Make sure to install air filters in the correct direction of airflow
Air Filters • Some owners may choose to replace their own filters or have their in-house maintenance personnel install the filters • There are many different types of filters available -- notify the customer of the various types so the best filter can be selected for the job
Fan Compartment • Check blower wheel for dirt build-up and clean when required • An important maintenance task • Dirt on blower wheel will reduce CFM delivered by fan • This may be a time-consuming task • May require removing entire drive assembly
Fan Compartment (Direct Driven Blowers) • Visually inspect fan motor for bearing wear by spinning fan wheel and notice how it slows down and stops • Check fan motor for excess end play • Some motors may have up to 1/8” end play • Check motor bearing for “oval shape” • There should be no vertical play with shaft • Lubricate motor, if required
Fan Compartment(Belt Driven Blowers) • Check belt tension for proper adjustment • 3/8” to 1/2” depression with a 10 lb. force • If possible, use a belt tension gauge • Visually inspect belt, bearing and pulley for signs of wear • Visually inspect pulley and drive alignment • use straight edge or string
Fan Compartment (Belt Driven Blowers) • Check pulley and drive set screws for tightness • Record belt size • When possible leave an extra belt on the job • Mark belt size on unit • Lubricate motor and fan bearings, when possible • Some motors have sealed bearings and external lubrication is not needed
Clean and Inspect Condensate Drain System • Inspect condition of the condensate line • Clear lines with compressed gas, if necessary • Inspect condensate pump, remove and clean if required