lodging hvac and refrigeration. goals guest comfort energy saving extend equipment life reduce...
TRANSCRIPT
Lodging HVAC and Refrigeration
Goals
• Guest comfort
• Energy saving
• Extend equipment life
• Reduce maintenance
• Reduce service calls
What we’ll talk about
• The purpose of HVAC
• A/C fundamentals
• Basic HVAC controls
• HVAC troubleshooting
• HVAC system adjustments
• Guest room PTAC
What we’ll talk about
• Refrigeration
Walk-in coolers and freezers
Under counter reach-ins
Display coolers
Guest room refrigeratorsIce maker fundamentals
Ice maker troubleshooting
Typical Hotel Electricity Usage
49%
20%
9%
11%
11%
HVAC Room
HVAC Common
Lights Common
Lights Room
Misc.
Source: Florida Power
Comfort
• Design airflow
• Space air distribution
• Outside air proportion
Indoor Air Quality(IAQ)
• Indoor air pollution• Material outgassing• Particulates
• Ventilation• Infiltration, natural, and mechanical• Fresh air proportion required by code.
HVAC Safety
• Loose hair, jewelry, wristbands, clothing
• Situational awareness
• Disconnect OFF
• Lock-out Tag-out
• Safety glasses
• Right tool for the job
VOM Basics
Alternating current (AC)
Direct current (DC)
Continuity
VOM Basics
Measuring voltage – Select type of power and rangeIf unsure select highest rangeMeasure voltage to ground
Checking fuses – Select Continuity (diode symbol)Place probes at each end of the fuseIf the fuse is good, then tone and reading 0
A/C Fundamentals
A/C FundamentalsStraight Cooling
A/C FundamentalsHeat Pump
Operation
• Cooling
Liquid line should be warm
Supply air should be about 15F lower than return air
Condenser discharge air should be warm
Operation
• Heating (heat pump)
Suction line should be warm
Supply air temp should be 100F – 115F
Condenser discharge air should be cold
Controls
Controls Thermostat Wiring (Straight Cool)
Controls Thermostat Wiring (Heat Pump)
ControlsStraight Cooling
Red Thermostat, Air Handler, Condenser
Yellow Thermostat, Condenser
White Thermostat, Air Handler
Green Thermostat, Air Handler
ControlsHeat Pump
Red Thermostat, Air Handler, Condenser
Yellow Thermostat, Condenser
White Thermostat, Air Handler, Condenser
Green Thermostat, Air Handler
Orange Thermostat, Condenser
Black Thermostat, Air Handler, Condenser
Problems
• A/C not working (Not running)
Power
Fuses at disconnect
24VAC to control board
Control board fuse
24VAC to thermostat
Power at thermostat terminals
Problems
24VAC at thermostat terminals
R to C
Y to C in cooling
W to C in heating
G to C in fan mode
If no C terminal read between R and appropriate terminal (Y, W, G). If there is power at the terminal there will be no reading.
Problems
• A/C not working (running)
Airflow temperature
Filters
Coils
Condenser operation
Problems
• Condenser troubleshooting
Power
Low voltage terminals
Discharge air temperature
Liquid line temperature (cooling)
Problems
• Space too hot/cold (A/C working)
Check for airflow
Filters
Dampers
Controls
Problems
• “Smudging” – Dirty filters Dirty coil Particle entrainment
• Squealing
On start-up - Belts slipping
While operating – Belts too tight
Problems
• Evaporator icing
Low airflow – Dirty filters
Dirty coil
Low refrigerant charge
• Condenser icingDirty coil
Low refrigerant charge
Revisiting the HVAC Systems
• Outside air
• Diffuser vanes
• Balancing dampers
• Fire dampers
• Controls
• Air handling equipment
Outside Air
Outside Air
• Ventilation air
• Required by code
• ASHRAE 62.1-2007
• Requirements vary by occupancy
• Amount for each system found in the balancing report.
Outside Air
• Direct measurement• Temperature method• Must be 15F – 20F difference between outside air and
return air temps.
• Formula: (MA – RA)/(OA – RA)
Where: MA = Mixed air temp
OA = Outside air temp
RA = Return air temp
Outside Air
Temperature method in action
Conditions: Outside air temp: 30FReturn air temp: 70FMixed air temp: 64F
Formula: (64 – 70)/(30 – 70) = 0.15
or 15% outside air.
Diffuser 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.
Balancing 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 open
Ensure that damper handle position corresponds to damper position
Fire 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.
Controls
• Ensure that the thermostat is level.
• Electronic thermostats programmed correctly.
Air Handling Equipment
• Change filters every monthOrient filters correctlyMore often in dirty environments (laundry)Pre-filters in dirty environments
• Clean coils annually
• Keep fans cleanExhaust fans
Air Handling Equipment
• Make sure that belts are tight and alignedRecommended ½” deflection
Pulleys should be in alignment
Grip-notch belts may solve slipping problems
• Ensure that drain lines are clear
• Drain pans slanted toward drain line
• Install float switchesWired between transformer and control board
PTAC
• Package Terminal Air Conditioner
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
Property Refrigeration
• Walk-in cooler and freezer• Under-counter reach-in• Display coolers
Not running - Power
Fuses
Running - Coils
Discharge air temperature
Liquid line temperature
Property Refrigeration
Guest room refrigerators• Power
• Coil
• Loaded
• Defrost
Ice Maker
Ice MakerFreeze Cycle
Ice MakerHarvest Cycle
Ice MakerTroubleshooting
• Download service manual from manufacturer
• Ice maker and bin may have different model numbers.
• Sequence of operations
• Trouble codes
• Troubleshooting help
Ice MakerTroubleshooting
• Leaks
Drain line intact
Over floor drain
Debris in ice bin
Water line
Ice MakerTroubleshooting
• Little or no ice
Clean condenser coil
Float switch
Ice curtain stuck
Water line obstruction
Wrapping Up
• Improve guest experience
• Save energy
• Extend equipment life
• Reduce maintenance
• Reduce service calls
• Questions?