CSLB C-20 HVAC ContractorCooling and RefrigerationMedium
What is the primary purpose of a suction line accumulator installed near the compressor inlet on some air-conditioning and heat pump systems?
- ATo filter solid debris and acid from the suction line
- BTo store excess liquid refrigerant and prevent it from reaching the compressor, protecting against flooding and slugging
- CTo meter refrigerant flow into the evaporator coil
- DTo superheat refrigerant vapor before it enters the compressor
Show answer & explanationAnswer & explanation
Correct answer: B. To store excess liquid refrigerant and prevent it from reaching the compressor, protecting against flooding and slugging
A suction line accumulator acts as a reservoir that traps liquid refrigerant and oil that may return from the evaporator during low-load or defrost conditions, metering it back slowly so only vapor reaches the compressor, preventing damaging liquid slugging.
Why the other options are wrong
- A. Filtering debris is the job of a suction line filter drier, not the accumulator.
- C. Metering into the evaporator is done by the TXV or orifice, unrelated to the accumulator.
- D. Superheating occurs naturally in the evaporator/suction line, not as the accumulator's main purpose.
Suction Line Accumulator
A component that traps liquid refrigerant and oil returning from the evaporator, preventing compressor flooding and slugging, common on heat pumps.
- Common on heat pumps due to defrost cycle liquid floodback
- Meters liquid back slowly via bleed hole
- Protects against compressor mechanical damage
Memory trick: Accumulator holds the liquid hostage until it's safe.