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Proper Wireless Probe Placement for Accurate Diagnostics in measureQuick

measureQuick at its core is a fancy computer. To get the right answers out, you have to put the right information in, meaning the probe placement is critical.

Note: When placing the probes, pay attention to the thermostat temperature reading and compare it to that of the return air. A significant difference between the two is an indicator of a potential return air leak from an unconditioned space or air leakage behind the thermostat through the wiring chase.

Indoor Probe Placement for Air Handlers

Probe Placement for Attic / Crawl Space Installation

measureQuick is designed to test from the system inlet (return) to the system outlet (supply) so the software can measure performance as well as to identify potential return air duct leakage. If measurements are made directly at the equipment, system losses may not be evident. The supply probe must ideally will be located in the first supply air register. It is CRITICAL that the supply air probe be inserted into the register and not installed at the face of the register to avoid issues with air entrainment. The return air probe can be placed at the face of the register. Placing the probes in this manner will allow the software diagnostics to perform optimally. For placement of the manometers for static pressure measurement see below.

Probe Placement for Furnaces

Probe Placement for Furnaces in measureQuick

measureQuick is designed to test from the system inlet (return) to the system outlet (supply) so the software can measure performance as well as to identify potential return air duct leakage. If measurements are made directly at the equipment, system losses may not be evident. The supply probe must ideally will be located in the first supply air register. It is CRITICAL that the supply air probe be inserted into the register and not installed at the face of the register to avoid issues with air entrainment. The return air probe can be placed at the face of the register. Placing the probes in this manner will allow the software diagnostics to perform optimally. For placement of the manometers for static pressure measurement see below.

Outdoor Probe Placement

For air conditioners the probes are placed exactly like you would use traditional gauges. Suction pressure is measured on the true suction or the vapor line. Liquid pressure at the liquid line. Suction line temperature at the suction service valve, at least 6″ from the compressor. Liquid line temperature measured at the liquid line service valve. Discharge temperature (optional) at the compressor discharge line at least 6″ from the compressor. Outdoor air temperature is measured out of line of the sun, ideally close to the middle of the condenser.

Manometer Probe Placement for Air Handlers

Manometer are used to measure return static, supply static and calculate total external static pressure. Probe placement is critical to get accurate readings. When thinking about Total External Static Pressure (TESP) it is best to think of it as available pressure external to the appliance being tested.

External static pressure should not exceed 140% of the rated static pressure or the performance of the air handler will significantly start to drop of if equipped with a PSC motor. If equipped with an ECM or X13 (constant airflow or constant torque) the motor will exhibit a higher than normal fan watt draw and or failure prematurely.

With an air handler, that means the coil is internal to the system and is included in the measurement. Meaning the only thing external to the air handler are the supply and rerun air ducting system. The filter may or may not be included. Typically the filter is not is not, and the TESP should be measured as shown below, after the filter. Because the coil is already included in the measurement, it is not uncommon for the TESP rating to be significantly lower than that of a furnace. Air Handlers are typically rated at .3″ to .5″ wc.

Manometer Probe Placement For Furnaces

Manometer are used to measure return static, supply static and calculate total external static pressure. Probe placement is critical to get accurate readings. When thinking about Total External Static Pressure (TESP) it is best to think of it as available pressure external to the appliance being tested. In this case, we are testing the furnace only.

External static pressure should not exceed 140% of the rated static pressure or the performance of the furnace/air conditioner will significantly start to drop of if equipped with a PSC motor. If equipped with an ECM or X13 (constant airflow or constant torque) the motor will exhibit a higher than normal fan watt draw and or failure prematurely.

With testing TESP on a furnace, the filter and evaporator coil are installed external to the furnace. The probes therefore must be placed in the cabinet return (post filter)and before the evaporator coil (Pre Coil). To do so you will be required to drill a hole (make a test port) in the appliance cabinet either in the door or on the side of the return, and below the evaporator coil in the front, back or side of the furnace. Metal plugs are available to plug the test ports. Furnaces typically are rated at .5″ wc.

Updated on November 30, 2021

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