Ritchie Yellow Jacket Instrument Applications

What is Dry Bulb? The dry-bulb temperature (DBT) is the temperature of air measured by a thermometer freely exposed to the air but shielded from radiation and moisture. DBT is the temperature that is usually thought of as air temperature. It is the true thermodynamic temperature.

What is Wet Bulb? The wet-bulb temperature is the temperature a parcel of air would have if it were cooled to saturation. The wet-bulb temperature is the lowest temperature that can be reached under current ambient conditions by the evaporation of water only. Wet-bulb temperature is largely determined by both actual air temperature (dry-bulb temperature) and the amount of moisture in the air (humidity). At 100% relative humidity, the wet-bulb temperature equals the dry-bulb temperature. Calculating BTU’s = CFM x ∆H x 4.5

What is Dew Point? External Static Pressure is the measurement of all the resistance in the duct system that the fan has to work against. It is the sum of the suction pressure (negative) and discharge pressure(positive) created by the equipment blower. Examples are: Filters grills Air Conditioning Coils Ductwork Sweating AHU’s

What is Enthalpy? (In the HVAC Industry) Atmospheric air is a mixture of dry air and water vapor. enthalpy of the dry air is sensible heat the enthalpy of moist air is the latent heat The total enthalpy = sensible + latent Calculating BTU’s = CFM x ∆H x 4.5

What is total External Static Pressure? Atmospheric air is a mixture of dry air and water vapor. enthalpy of the dry air is sensible heat the enthalpy of moist air is the latent heat The total enthalpy = sensible + latent Calculating BTU’s = CFM x ∆H x 4.5

Digital Sling Psychrometer °F/°C switchable Data hold Auto power off Display relative humidity and temperature simultaneously Response time of 60 seconds to changes in humidity 69008

Anemometer Air flow ranges: 125 – 4900 ft/min Resolution: 1 ft/min and 0.01 m/sec. Accuracy: ±2% Temperature: 14° to 122°F (-10° to 50°C) Resolution: 0.01°F and 0.1°C Accuracy: ±1.0°F (±0.6°C) Power: 9V battery, battery life approximately 100 hours Fan diameter: 2-7/8″ (70 mm) 68915

Digital Thermometer Temperature range: -328° to 1999°F (-200° to 1300°C) Operating temperature range: 32° to 122°F (0° to 50°C) (0-85% RH, non-condensing) Sampling rates: 2.5 per second Battery: 9V, battery life approximately 200 hours Display: LCD 1.5″ x 1.7″ (37 mm x 42 mm), maximum reading 1999 Dimensions: 7.1″ x 2.8″ x 1.2″ (181 mm x 71 mm x 30 mm) Accuracy: -200° to 1300°C ± (0.3% of reading + 1°C) 1000° to 1300°C ± (0.5% of reading + 1°C) -328° to 2372°F ± (0.3% of reading + 2°F) (18° to 28°C ambient temperature) 69233

Digital Manometer Measures gas pressure, static pressure and pressure differential Measure gas pressure on the inlet and outlets with the standard 1/8 NPT fittings or directly with the adapter for WR gas valves Take static pressure measurements using the resolution mode of 0.01inWC Read pressure differential measurements across a blower directly Includes a easy to use zero function Auto Power-Off (APO) conserves battery life Measures pressure between -19.95 and 19.95inWC (inches of water column) Individual P1 or P2 measurements can be made by disconnecting the other port thus referencing the measured pressure to atmospheric pressure   78052

69233 Digital Thermometer Application: Infiltration Complaint: Customer complains that his system seems to run quite often and his electric / fuel bill is high.

69233 Digital Thermometer Application: Infiltration Test: Take three data measurements Space air temperature Mixed air temperature (return air temperature) Outside air temperature

69233 Digital Thermometer Application: Infiltration Space Temperature Mixed Temperature Outside Temperature

69233 Digital Thermometer Application: Infiltration MA = Mixed air ST = Space Temperature OA = Outside air IA%= ((MA-ST) / (OA-ST))x 100

69233 Digital Thermometer Application: Infiltration MA= 80º ST = 70º OA = 95º IA% = ((80º-70º) / (95º-70º)) x 100 IA% = (10 / 25) x 100 IA% = 40% This reading is easily taken with (3) 69233 placements.

69233 Digital Thermometer Application: Infiltration Diagnosis: The amount of outside air entering the space is unusually high. Even though we did not conduct the test, I would expect the relatively humidity to be elevated. This could be verified with another test using the Digital Sling Psychrometer 69008

69008 Psychrometer / 68915 Anemometer Application: System Capacity Complaint: Customer complains that his system 3 ton system seems to run quite often and his electric / fuel bill is high and the house is not cooling on warm days.

69008 Psychrometer / 68915 Anemometer Application: System Capacity Test: Determine the total heat removed from the space by measuring the change in enthalpy Total Heat (BTU/hr) = 4.5 x cfm x Δh (std. air) 4.5 = the cooling BTU multiplier at sea level, or .075-lbs. of air per CFM x 60 (minutes in an hour.) ∆h is the difference between wet bulb return Temperature and wet bulb supply Temperature converted to Enthalpy

69008 Psychrometer / 68915 Anemometer Application: System Capacity Supply Air Flow Supply Wet Bulb Return Wet Bulb

69008 Psychrometer / 68915 Anemometer Application: System Capacity Supply Wet Bulb Return Wet Bulb

69008 Psychrometer / 68915 Anemometer Application: System Capacity Return wet bulb = 69º Supply wet bulb – 62º Convert to enthalpy from chart 33.25 – 27.85 = 5.4 Enthalpy change CFM = 1,200 1,200 x 4.5 x 5.4 = 29,160 btu’s

69008 Psychrometer / 68915 Anemometer Application: System Capacity Diagnosis: The system is under performing as indicated by low change in enthalpy.

69008 Psychrometer Application: Damp Air Complaint: when we return from the weekend the temperature in the office is cool but very uncomfortable. It feels damp. By the afternoon the temperature is fine and the dampness seems to be gone. This also happens during the week but it does not seem as bad.

69008 Psychrometer Application: Damp Air Test: Take a sample reading of the space on Friday Afternoon Dry Bulb Temperature Wet bulb Temperature Take a sample reading of the space on Monday Morning

69008 Psychrometer Application: Damp Air Test: Friday Conditions: DB = 73 WB = 59 RH = 50.6% Monday Conditions: DB = 75 WB = 68 RH = 72.6%

69008 Psychrometer Application: Damp Air Diagnosis: Since the thermostat is set to unoccupied mode (weekend mode) both temperature and humidity rise. When the system is commanded to occupied (week day mode) the unit will cool the air but does not stay on long enough to reduce humidity.

78052 Digital Manometer / 68915 Anemometer Application: Low Air Flow Complaint: Customer complains that the system is not providing enough cool air to all areas.

78052 Digital Manometer / 68915 Anemometer Application: Low Air Flow Test: Measure total Return Air Volume Measure total Supply Air Volume Measure the Total external Static Pressure

78052 Digital Manometer / 68915 Anemometer Application: Low Air Flow Test: RA = 1,185 cfm SA (room A) = 125 cfm SA (room B) = 345 cfm SA (room C) = 200 cfm SA (room D) = 240 cfm SA (Total) = 910 cfm

78052 Digital Manometer / 68915 Anemometer Application: Low Air Flow Test: Measure the Total External Static pressure of the system by placing the probes of the 78052 Manometer in the Return and Supply Plenums. TSP = .09”

78052 Digital Manometer / 68915 Anemometer Application: Low Air Flow Diagnosis: The Total External Static Pressure appears to be high. The Total Supply Air is significantly lower than the total Return Air. The high Total External Static Pressure may be caused by a dirty filter, dirty coil, or under sized supply duct. The low supply air volume may be caused by leaky ductwork.