Danfoss 034L0058 KVL 22 Crankcase Pressure Regulator, 22 mm

KVL 22: a crankcase pressure regulator that protects the compressor from overload

Danfoss 034L0058 is a KVL 22 crankcase pressure regulator with 22 mm (7/8 in) ODF solder connections. It limits the pressure at the compressor inlet to a set maximum, so that after a defrost or a long off period the motor is not overloaded by a high suction pressure. The range is 0.2 to 6 bar (3 to 87 psig) with a factory setting of 2 bar (29 psig).

The valve closes when the pressure after it rises above the setting. Kv is 3.2 m3/h at a proportional band of 2 bar, the maximum working pressure is 18 bar (260 psig) and the medium temperature range is -60 to 130 C. UL, EAC and UA approvals are listed.

Technical specifications

Protecting compressors after defrost and start-up

A KVL sits in the suction line in front of the compressor. After a defrost or a restart the evaporator may be warm, and gas at a high density would load the motor excessively. The KVL throttles the flow until the pressure falls to a safe value, so a smaller motor can be selected or an existing motor can be protected.

Listed capacities at the stated conditions are 6.3 kW on R404A/R507A, 5.3 kW on R134a, 7.1 kW on R22 and 6.5 kW on R407C; R1234ze(E) and R513A are listed for oil-free use. The Danfoss data sheet gives capacity curves against pressure drop.

Fitting and checks before ordering

Install in the suction line with the arrow in flow direction, close to the compressor, and set the pressure with the spindle while watching a gauge. Wrap the body in a wet cloth when brazing. A KVL does not control the evaporator; for that, use a KVP.

The page lists 034L1065 as an identical product and the customer part number 00A386. Confirm refrigerant, pressure setting, connection size and capacity before ordering, and check the compressor manufacturer maximum suction pressure.

Other types and sizes from the same Danfoss family that appear in the Danfoss store listing include KVL 12 (034L0041), KVL 15 (034L0042), KVL 28 (034L0046), KVL 35 (034L0052), KVL 10 (034L1180). These are listed for orientation only; each has its own datasheet values, so check size, connection and version before ordering.

Related Danfoss products: Danfoss 027H2308 ICSH 25 Dual-Position Servo Valve, 25 mm, Danfoss 027H2081 ICS3 25-10 Pilot-Operated Servo Valve, 25 mm, Danfoss 034L1075 KVP 22 Evaporator Pressure Regulator, 22 mm, Danfoss 034N0084 CPCE 22 Hot Gas Bypass Capacity Regulator and Danfoss 148H3402 ORV 40 Oil Temperature Regulating Valve, 40 mm.

How the KVL regulates

According to the Danfoss KVL data sheet, the crankcase pressure regulator opens on a pressure fall on the outlet side, that is, when the suction pressure ahead of the compressor drops below the set value. The KVL regulates on the outlet pressure only. Pressure variations on the inlet side do not affect the degree of opening, because the valve uses equalization bellows. A damping device protects the regulator against the pressure pulsations normally found in a refrigeration system, and the internal parts include a setting screw, main spring, valve plate and valve seat under a protective cap.

Danfoss notes that, because optimum operation of the plant is best reached with the KVL fully open, the term offset is not normally used in connection with this valve. In practice the regulator only throttles during the critical periods after a long standstill or after defrost, and is fully open in normal running.

Technical data from the data sheet

• Regulating range: 0.2 to 6.0 bar, factory setting 2 bar
• Maximum working pressure PS/MWP: 18 bar; maximum test pressure Pe: 19.8 bar
• Medium temperature range: −60 to 130 °C
• Maximum P-band (KVL 12 to 22): 2 bar
• Kv value with maximum P-band (KVL 12 to 22): 3.2 m³/h
• Rated capacity of the KVL 12 to 22 sizes: 7.1 kW (R22), 5.3 kW (R134a), 6.3 kW (R404A/R507) and 6.4 kW (R407C), at suction temperature −10 °C, condensing temperature 25 °C, 0.2 bar pressure drop and 0.6 bar offset

Sizing and noise

Danfoss warns that the connection dimension must not be too small, because gas velocities above 40 m/s at the regulator inlet can cause flow noise. For refrigerants or conditions other than the rated ones, Danfoss recommends selecting with its Coolselector®2 software. Spare parts listed for the KV range include a service kit with cap, gasket and screw, and a counter (locking) screw for KV 12, 15 and 22. Send us the refrigerant, compressor capacity and the maximum suction pressure allowed by the compressor maker, and we can confirm the selection.

Documents and quotation

Attached for download: Danfoss Crankcase pressure regulator, KVL AI555531791071en-000101 (manufacturer, unaltered), the manufacturer’s unaltered PDF. Browse comparable products in regulators. To order, send us 034L0058 and the required quantity; Seven Star LLC is an independent supplier based in Muscat.