Air Cooler Expansion Valve Selection, Sizing & Installation Position
Thermal expansion valve is the throttle component feeding liquid refrigerant into air cooler; it controls flow rate according to superheat at evaporator outlet. Correct superheat target for most air cooler: 4–6 K; too low superheat causes liquid flood-back; too high superheat reduces coil utilization and cooling capacity. Expansion valve capacity must match air cooler nominal cooling load; oversized valve hunts and fluctuates; undersized valve limits maximum cooling output. Bulb of thermal expansion valve must be tightly fixed on suction pipe, insulated from ambient air, to accurately sense refrigerant gas temperature. Xiteliduo air cooler HS 84186120 can be pre-matched with expansion valve assembly for R404A, R507, R448A and other low-GWP refrigerants. Multi-fan single coil air cooler uses one main expansion valve; multi-circuit air cooler equips independent expansion valve for each refrigerant circuit. Blast freezer air cooler works at large pressure ratio; expansion valve needs special low-temperature diaphragm to maintain stable regulation. Expansion valve cannot be installed after suction accumulator; it must be placed before air cooler liquid inlet, close to coil to reduce flash gas. Air cooler for high ambient fluctuation project needs external equalizer expansion valve when suction pipe pressure drop is obvious. Refrigeration maintenance & repair company calibrates superheat after air cooler cleaning, defrost overhaul or refrigerant recharging work.
FAQ
- What is the standard target superheat setting for air cooler? 4–6 K.
- What risk if expansion valve superheat is set too low? Liquid refrigerant flows back to compressor and causes slugging.
- What happens when expansion valve is oversized for air cooler? Flow hunting, unstable suction pressure and temperature fluctuation.
- Where to fix expansion valve temperature sensing bulb? Tightly strapped on suction pipe, with thermal insulation wrapping.
- Does multi-circuit air cooler need separate expansion valve per circuit? Yes, independent valve for each refrigerant loop.
- What special design requirement for blast freezer expansion valve? Low-temperature resistant diaphragm for stable regulation under big pressure ratio.
- What type expansion valve is required when suction pipe pressure loss is large? External equalizer thermal expansion valve.
- When to re-calibrate expansion valve superheat? After coil cleaning, defrost repair or refrigerant charging adjustment.
