Pressure and Temperature Symptoms Chart
This document contains a Pressure and Temperature Symptoms Chart.
All Cooling Units.
All Product models, all serial numbers.
The purpose of this document is to provide a clear communication on what the relationship between pressure, temperature, and the use of Superheat and Subcooling to troubleshoot.
Pressure and Temperature Symptoms Chart:
|Symptoms Exhibited *||Condition Solutions|
|↓||↓||↓||↓||↓||Light load||Check filter, blower speed tap selected, blower motor, wheel, and capacitor.|
|↓||↓||↑||↓||↓||Insufficient refrigerant charge; undercharge; leak||Check system for leak(s). Recover refrigerant, repair leak(s), evacuate system to 500 microns, and re-charge with refrigerant.|
|↓||↓||↑||↑||-||Restriction in refrigerant circuit||Look for significant temperature difference at point of restriction. Possible incorrect orifice pin (too small) or TXV stuck closed.|
|↑||↑||↑||↑||↑||Heavy load||Due to excessive air flow across coil or open return duct in unconditioned space. Check blower speed tap setting (too high) and return duct for leakage.|
|↑||↑||↓||↓||↑||Restricted outdoor coil||Insufficient air flow across Condenser coil. Check cleanliness of coil. Check condenser fan motor, blade, and capacitor.|
|↑||↑||↓||↑||↑||Excessive refrigerant charge; overcharge||Recover refrigerant from system and weigh in refrigerant|
|↑||↑||↓||↕||↑||Air and/or Non-condensable in system||Recover refrigerant from system, evacuate system to 500 microns, and weigh in refrigerant.|
|↑||↓||↓||↓||-||Over feeding Metering device||Check for proper pin size or loose TXV sensing bulb or TXV stuck open.|
|↑||↓||↕||↕||-||Compressor defective||I.E. runs but doesn't pump, abnormally low Amp draw and abnormally high compressor temperature may be indicated.|
|* "Normal" refers to Pressures, Temperatures, and/or values obtained at rated air flow under a given set of conditions and assumes that no changes have been made to factory refrigerant charge.|
Published for:APC Belgium
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