Preventive Maintenance Flashcards

Rationale for Electrical Preventive Maintenance

Maintaining electrical systems is critical, especially during winter months when power requirements increase as facilities struggle with heating and asset operation. In the current economic environment, utility cost reduction is a priority for facility and plant managers. While training and equipment like Programmable Logic Controllers (PLC) are useful, they are not substitutes for a comprehensive preventive maintenance (PM) program.

Ten Reasons to Perform Electrical Preventive Maintenance

• Avoid Electrical Shorts and Fires: Short circuits occur due to overloaded wires, exposed wiring, and load imbalances. These conditions lead to excessive heat buildup, arcing, or explosions.
• Identify Loose Connections: Loose connections cause power fluctuations, erratic device operation, and uneven load distribution across conductors.
• Monitor Component Operating Temperatures: Transformers, motors, bearings, and wires typically exhibit elevated temperatures before failure. Predictive maintenance technologies—including infrared thermography, vibration analysis, and laser alignment—along with regular lubrication can prevent asset failure.
• Identify Sensory Warning Signs: Physical inspections are required to detect unusual smells (such as melting insulation), noises (stressed motors), dust buildup, or discoloration (corrosion). Electrical troubleshooting should always follow a systematic approach.
• Check Emergency Systems: Disasters often occur because safety monitoring equipment, such as emergency lighting, signage, and power indicator displays, is faulty, providing a false sense of security.
• Extend Asset Lifecycle: Poorly maintained assets require higher energy consumption to perform the same work, leading to excessive wear and tear and a shortened useful lifecycle.
• Avoid Unplanned Downtime: Unexpected failures shut down production and result in emergency labor costs and unnecessary capital replacement. These factors significantly impact organizational profitability.
• Minimize Equipment Loss: Consistent PM reduces the frequency of early equipment replacement caused by electrical malfunctions.
• Energy Savings: Equipment achieves optimal energy efficiency only when functioning within design parameters and when well-maintained.
• Safety and Liability: Safety is the paramount reason for PM. Avoiding injury or death is the highest priority. Facilities with poor maintenance records are high-risk targets for liability litigation.

Frequency and Scope of Electrical PM

• Thorough Inspections: A licensed electrician should conduct a thorough inspection of electrical systems every $3$ to $5$ years.
• Asset-Specific Maintenance: Individual assets must be inspected according to manufacturer guidelines or based on industrial training and environment experience. Examples include:
  • Motors: May require quarterly inspections.
  • Air Handlers: Typically inspected annually.
• CMMS Integration: Computerized Maintenance Management System (CMMS) software is the preferred method for scheduling, recording results, and documenting notes for PM activities and work orders.

Sample Electrical PM Checklist Items

• Re-torqueing connections.
• Checking panel boards.
• Inspecting PLCs for effectiveness.
• Examing work orders and new installations for compliance and uniformity.
• Verifying that lock-out tags are in place.
• Inspecting heating and cooling units.
• Testing lighting and GFCIs (Ground Fault Circuit Interrupters).
• Checking shutdown mechanisms.
• Ensuring National Electrical Code (NEC) compliance.

Electrical PM Technology Tools

Efficiency and reliability in PM are enhanced by various technological tools, chosen based on asset type, location, and accessibility. Note that all repair and installation work must be performed by a licensed electrician.

• CMMS/EAM Software: Used for asset management, scheduling PM/predictive maintenance, tracking work orders, and managing vendor contracts for outsourced work.
• Programmable Logic Controllers (PLC): Used for machinery control (assembly lines to lighting). They are designed for multiple inputs/outputs, extended temperature ranges, immunity to electrical noise, and resistance to vibration/impact.
• Maintenance Methodologies: Includes Condition-Based Maintenance (CBM) and Reliability-Based Maintenance.
• Infrared Thermography: A predictive tool for identifying heat changes or moisture. Moisture often leads to corrosion.
• Vibration Analysis: Detects unwanted vibrations in motors, which indicate energy loss.
• Ultrasonic Analysis: Detects high-frequency sounds inaudible to humans to identify "tightness" or issues.
• Laser Alignment: Specifically laser shaft alignment, which increases motor efficiency and slows wear.
• The Senses: Visual inspection, smell, and noise detection are the most frequently used forms of problem identification.

Proactive Plumbing Maintenance

Plumbing systems require a proactive checklist covering pipes, valves, heaters, and drains to prevent catastrophic failure.

• Active Leaks: Inspections must look for water spots, moisture, puddles, mold, or mildew. Unrepaired leaks can waste thousands of gallons of water annually.
• Corrosion Signs: Check visible pipes for corrosion and faucets/showerheads for lime scale. Significant corrosion indicates the end of the pipe's useful life.
• Water Pressure Standards:
  • Pressure should be no higher than $80\,psi$ and no lower than $40\,psi$.
  • In multi-story buildings, pressure is often higher on lower levels and lower on upper levels.
  • Excessive pressure damages pipes, while insufficient pressure leads to resident complaints.
• Valve Operation: Safety and shutoff valves must be tested for correct operation. Replacing broken valves allow for sectional shutdowns during major blowouts rather than shutting off the entire building.
• Water Heater Inspection: Check for proper temperature, obvious leaks, and test safety valves/overflows. Safety repairs must be immediate.
• Drain Maintenance: Test flow rates. Slow or clogged drains require power-rodding or hydrojetting. Camera inspections are recommended to check for root infiltration or "bellying" (sagging) in the lines.
• Backflow Testing: Commercial and large multi-unit residential buildings require annual backflow prevention testing to ensure the water system is not contaminated by backward-flowing chemicals or substances.

Residential and Small Business Plumbing Checklist

• Exposed Pipes: Check walls and foundations for puddles or watermarks.
• Corrosion Indicators:
  • Green stains on brass and copper fittings/shutoff valves.
  • Yellow or orange stains on old steel pipes.
• Fixture Performance: Low pressure in faucets or showerheads often signals sediment buildup or water line issues.
• Drainage Health: Drains should have a full "swirl." Bubbles indicate problems; gurgling sounds suggest venting issues. Slow drainage suggests a clog or a blocked vent pipe.
• Toilet Inspection:
  • Check flushing handles and internal tank parts for rust or breakage.
  • Ensure water does not run continuously.
  • Verify there is no water on the floor around the base.
  • Push/pull the toilet to ensure it does not rock (rocking indicates a loose seal).
• Structural Signs: Cracked, loose, or hollow tiles in wet areas suggest rot or leaking behind the wall. Water through tile cracks can appear as a leak on the ceiling below.
• Water Heater Specifics:
  • Check the burner chamber for rust flakes.
  • Identify flame color: should be blue. A yellow flame indicates the jets need cleaning.
  • Drain the heater periodically to remove sediment.
• Washing Machine Hoses: Check for cracks or brittleness. High-pressure material like braided stainless steel is recommended to avoid insurance claims.

HVAC Preventative Maintenance

Bi-annual maintenance ensures system efficiency. Dealers often provide priority service for customers with maintenance agreements.

Outdoor Unit Tasks

• Inspect and adjust refrigerant levels.
• Clean dirt, leaves, and debris from the cabinet.
• Clear obstructions from the base pan drain openings.
• Clean coils and the cabinet.
• Inspect fan motor and blades; lubricate older models.
• Check control box components: contactors, relays, circuit boards, capacitors, and sump heat.
• Inspect the compressor and associated tubing for damage.

Indoor Unit Tasks

• Clean blower assembly (housing, wheel, and motor).
• Lubricate motor and replace fan belts on older models.
• Clean lint/debris from combustion blower housing.
• Clean evaporator coil, drain pan, and condensate lines.
• Inspect gas furnaces for gas leaks.
• Clean and adjust burner assembly and ignition/safety controls.
• Inspect heat exchanger/heating elements and the flue system for corrosion or dislocation.
• Clean or replace air filters and check ductwork for leaks.

Operational Monitoring

• Measure outdoor dry bulb temperature.
• Measure indoor dry and wet bulb temperatures.
• Measure high- and low-side system pressures.
• Monitor gas furnace manifold pressure and line pressure.
• Measure temperature rise and adjust airflow.
• Monitor line/load volts and amps.

Energy Conservation and Efficiency Strategies

• Cooling Settings: Set thermostats as high as comfort allows. Lower the setting by a degree or two only when expecting large groups of people.
• Ventilation and Shielding: Use attic vents to relieve heat. Draw blinds/drapes or install awnings to block direct sunlight.
• Thermostat Placement: Do not place heat-producing devices (TVs, lamps) beneath wall-mounted thermostats, as this causes overcooling.
• Insulation (R-Values):
  • Ceilings: $R-30$ ($10"$).
  • Exterior walls/floors over unheated areas: $R-11$ ($3-1/2"$).
• Infiltration Control: Outside air infiltration accounts for $15\%$ to $30\%$ of air conditioning energy requirements. Use caulking and weather-stripping around doors and windows.
• Windows: Double-glazing and low-e glass can reduce heat transfer by $40\%$ to $50\%$. Keep windows and doors closed to minimize heat gain/loss.
• Fireplaces and Humidity: Use tight-fitting dampers. Use a humidifier in winter to stay comfortable at lower temperature settings.

Ten Steps to Prolong HVAC Life

1. High-Efficiency Filters: Use pleated filters with an electrostatic charge.
2. Filter Rotation: Replace at least every $90$ days; check monthly. Households with pets should change filters monthly.
3. Clearance: Maintain at least $2\,feet$ of clearance around outdoor units.
4. Weekly Cleaning: Remove debris (leaves, pollen, twigs) from outdoor units. Ensure lawn mowers do not discharge grass onto the unit.
5. Refrigerant Line Insulation: Inspect monthly and replace if damaged.
6. Leveling: Annually ensure the outdoor unit is on firm, level ground or pads.
7. Condensate Drain: Annually pour a mixture of bleach and water down the drain to prevent mold and algae clogs.
8. Humidifier Care: Shut off the water supply to the furnace humidifier in summer. In fall, replace the wick filter, set the humidistat to between $35\%$ and $40\%$ relative humidity, and restore water supply.
9. Register Management: Never close more than $20\%$ of a home's registers to avoid system strain.
10. Safety: Replace the carbon monoxide detector battery annually.