6ComfortDesign airflowSpace air distributionOutside air proportion
7Indoor Air Quality (IAQ) Indoor air pollutionMaterial outgassingParticulatesVentilationInfiltration, natural, and mechanicalFresh air proportion required by code.
8HVAC Safety Loose hair, jewelry, wristbands, clothing Situational awarenessDisconnect OFFLock-out Tag-outSafety glassesRight tool for the job
9VOM BasicsAlternating current (AC)Direct current (DC)Continuity
10VOM Basics Measuring voltage – Select type of power and range If unsure select highest rangeMeasure voltage to groundChecking fuses –Select Continuity (diode symbol)Place probes at each end of the fuseIf the fuse is good, then tone and reading 0
19Controls Straight Cooling Red Thermostat, Air Handler, CondenserYellow Thermostat, CondenserWhite Thermostat, Air HandlerGreen Thermostat, Air Handler
20Controls Heat Pump Red Thermostat, Air Handler, Condenser Yellow Thermostat, CondenserWhite Thermostat, Air Handler, CondenserGreen Thermostat, Air HandlerOrange Thermostat, CondenserBlack Thermostat, Air Handler, Condenser
21Problems A/C not working (Not running) Power Fuses at disconnect 24VAC to control boardControl board fuse24VAC to thermostatPower at thermostat terminals
22Problems 24VAC at thermostat terminals R to C Y to C in cooling W to C in heatingG to C in fan modeIf no C terminal read between R and appropriate terminal (Y, W, G). If there is power at the terminal there will be no reading.
23Problems A/C not working (running) Airflow temperature Filters Coils Condenser operation
24Problems Condenser troubleshooting Power Low voltage terminals Discharge air temperatureLiquid line temperature (cooling)
25Problems Space too hot/cold (A/C working) Filters Dampers Controls Check for airflowFiltersDampersControls
30Outside Air Ventilation air Required by code ASHRAE 62.1-2007 Requirements vary by occupancyAmount for each system found in the balancing report.
31Outside Air Formula: (MA – RA)/(OA – RA) Where: MA = Mixed air temp Direct measurementTemperature methodMust be 15F – 20F difference between outside air and return air temps.Formula: (MA – RA)/(OA – RA)Where: MA = Mixed air tempOA = Outside air tempRA = Return air temp
32Temperature method in action Outside AirTemperature method in actionConditions: Outside air temp: 30FReturn air temp: 70FMixed air temp: 64FFormula: (64 – 70)/(30 – 70) = 0.15or 15% outside air.
33Diffuser Vanes Control diffusion and mixing in the space. Improper adjustment can lead to stagnant zones and drafty areas in the space.Usually set vanes at 45 degree angle from the center on sidewall diffusers.
34Balancing Dampers Located in ductwork prior to grilles. Usually located immediately prior to grille or at ductwork branch.If little to no flow at grille:Verify that damper is openEnsure that damper handle position corresponds to damper position
35Fire Dampers Located in ductwork at fire-rated partitions. If there is no airflow to a space, check the fire dampers.Visual inspection through access doors in ductwork.
36Controls Ensure that the thermostat is level. Electronic thermostats programmed correctly.
37Air Handling Equipment Change filters every monthOrient filters correctlyMore often in dirty environments (laundry)Pre-filters in dirty environmentsClean coils annuallyKeep fans cleanExhaust fans
38Air Handling Equipment Make sure that belts are tight and alignedRecommended ½” deflectionPulleys should be in alignmentGrip-notch belts may solve slipping problemsEnsure that drain lines are clearDrain pans slanted toward drain lineInstall float switchesWired between transformer and control board
39PTAC Package Terminal Air Conditioner Line fuse – 15A buss fuse PowerLine fuse – 15A buss fuse24VAC to control boardControl board trouble codePower at control board terminals3A buss fuseNo power from board – replaceCompressor makes ‘chugging’ noise – dying
40Property Refrigeration Walk-in cooler and freezerUnder-counter reach-inDisplay coolersNot running - PowerFusesRunning CoilsDischarge air temperatureLiquid line temperature