Nate Heat Pump Test
An electronic leak detector can typically detect a leak rate as small as:
1⁄2 ounce per year
Heat pumps are typically sized for the conditioned space based on the:
Cooling load Which of the following is used to make accurate residential load calculations?ACCA Manual J
When changing out an indoor coil the installer must be certain to:
Plumb the cabinet so its sides are vertical What is the effect of 170 volts supplied to a 208/230 volts compressor?Current increases and the motor may trip on overload Refrigerant subcooling is a measurement of the difference between Condensing saturation temperature and liquid line temperature.The voltage most often used to power the outdoor unit in a residential system is:.240V single phase.
To properly set a heat anticipator it is necessary to check the:
Heating control circuit amperage draw What can cause a lower than normal suction pressure A restricted drier What is a primary consideration when bending soft copper tubing into a bend of any radius?The cross-sectional are of the tube must not be significantly reduced When is vapor line condensation of a residential heat pump in the cooling mode a concern?Routing refrigerant line within a wall
Bent vanes on a direct drive blower wheel in an air handler can cause:
Loss in airflow, excessive blower motor wear, and increased noise 1 / 2
A technician measures the return air temperature of a 100,000 Btu output furnace to be 65 F and the supply side air temperature is 135 F. What is the SCFM (standard CFM)?
1323 SCFM
What would cause a voltage reading across a closed contact in a 24V control circuit?Pitted or dirty contacts A reason for cool air complaints when a heat pump is operating in the heating cycle is: Excessive supply air velocitie
The purpose of performing a duct traverse is to determine the average duct:
Airflow using multiple CFM readings taken from several locations across the cross section of the duct.When fabricating ductboard for a horizontal duct 36" X 24", which of the following is a preferred method for preventing wall deflection?Use 12 gauge rods, both horizontally and vertically at a minimum of every 16" What is used to measure duct static pressure?Differential pressure gauge To more accurately sense the refrigerant temperature of horizontal suction line that are 1 1⁄2 or lager, a thermostatic expansion valve sensing bulb should be mounted at which positions?
- or 8 o'clock
What are the first two checks typically made on an electronic control?Presence of proper input signals and proper output voltages The technician suspects that an outdoor thermostat used to bring on auxiliary heat may be out of calibration. The thermostat is a close-on-fall type that is adjustable. One method for checking the
thermostats calibration is to:
Manually rotate the shaft until the thermostat closes and compare the dial setting to an accurate outdoor temperature reading plus 10 F In an economizer system, when the outdoor air enthalpy exceeds setpoint, the outdoor air enthalpy exceeds setpoint, the outdoor air damper Closes to a preset minimum position What effect does a low charge have on the switchover operation of a reversing valve?Reversing valves are less likely to shift if charges is very low What is an effective method for reducing the transmissions from an air handler installed in a closet?Place the cabinet on an isolation pad
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