Question 85Refrigeration/AC - 1st Asst/Chief70% to pass
If the running suction pressure at the refrigeration compressor of a TXV controlled air- cooled refrigeration system is below normal, which of the following can be a cause?
AI Explanation
The correct answer is D) a restricted liquid-line strainer.
A restricted liquid-line strainer can cause the running suction pressure at the refrigeration compressor to be below normal in a TXV controlled air-cooled refrigeration system. This is because a restricted strainer will reduce the flow of liquid refrigerant to the expansion valve, causing it to not open fully. This reduction in refrigerant flow will result in lower suction pressure at the compressor.
The other options are incorrect because: A) overfeeding by the expansion valve would cause higher suction pressure, not lower; B) a dirty condenser would cause higher head pressure, not lower suction pressure; and C) a refrigerant overcharge would cause higher head pressure and suction pressure, not lower suction pressure.
Related Questions
#83 What is the purpose of running a refrigeration compressor in short intermittent spurts or throttling the suction isolation valve when starting the system after a prolonged shutdown? #84 An air-cooled refrigerated container unit using R-134a as a refrigerant has a box temperature set point of -15°F, but it is currently operating with a stable return air temperature of 0°F. The fresh air makeup vent is closed, the unit is operating at 460 VAC/60 Hz, and the unit is in full capacity cool (modulating valve 100% open). Using the illustrated troubleshooting guide, what would be the normal range of expected discharge pressures if the ambient air temperature is 90°F? Illustration GS-RA-52 #86 Low compressor head pressure in a refrigeration system can be caused by which of the following? #87 High suction pressure accompanied by low suction temperature to a refrigeration system compressor is caused by which of the following? #88 If increasing the cooling water flow to a refrigeration condenser fails to lower the condenser pressure, the probable cause may be due to what condition?