Danfoss KVL Series

The Danfoss KVL is a crankcase pressure regulator fitted in the suction line immediately ahead of the compressor. It opens on pressure fall on its outlet side — i.e., when suction pressure ahead of the compressor drops below the set value — throttling flow to protect the compressor motor from overload at high suction pressures, such as after start-up, hot gas defrost, or long standstill periods.

The KVL regulates on outlet pressure only: pressure variations on the inlet side do not affect the degree of opening, because the valve carries an equalization bellows with an effective area matching the valve seat. An integrated damping device protects against the pulsations that normally occur in suction lines near the compressor, ensuring long service life without impairing regulation accuracy.

Types available: Danfoss KVL 12, KVL 15, KVL 22 and the larger KVL frames. Send us the compressor duty, refrigerant and suction line size and we will confirm the frame and connection.

Fit a KVL when the compressor motor trips on overload after a hot gas defrost, after a long shutdown, or on a pull-down from warm — the classic symptom being a machine that runs fine in steady state but draws too much current every time suction pressure comes up.