Danfoss 120Z0892 Belt-Type Crankcase Heater – 65 W / 230 V | For MLZ 030-076, LLZ

Danfoss 120Z0892 is a belt-type crankcase heater wrapped around the outside of the compressor body like a belt. 65 W / 230 V is its power rating, and in the Danfoss catalog it is specified primarily for MLZ/MLM 030-076 and LLZ series scroll compressors, as well as the HCM094-120, HCP094-120, HCJ091-121 and DCJ091-121 models. In the field it is also known as a crankcase heater or crankcase resistor.

Keeps the Oil Warm While the Compressor Is Off — Prevents Oil Foaming and Liquid Slugging at Start-Up

When the compressor stops, the refrigerant migrates to the coldest point in the system. In cold weather and during long shutdowns, this point is often the compressor crankcase: the refrigerant condenses there and dissolves in the oil. Diluted oil cannot do its lubricating job.

When the compressor starts again, the crankcase pressure drops suddenly and the refrigerant in the oil boils and foams (oil foaming). The oil is ejected from the compressor with the foam; the result is dry friction in the bearings and, in severe cases, liquid slugging and damage to the scroll set. This risk is higher in LLZ units running at low temperatures and MLZ condensing units installed outdoors.

The crankcase heater breaks the first link in this chain: by keeping the oil warmer than the surroundings, it prevents the refrigerant from condensing in the crankcase.

Technical Specifications (Official Danfoss Catalog)

• Brand / Code: Danfoss 120Z0892 (original code) · EAN 5702424685683
• Type: belt type, wrapped around the outside of the body
• Power / Voltage: 65 W / 230 V
• Suitable compressors: Danfoss MLZ/MLM 030-076 · LLZ (all models) · HCM094-120 · HCP094-120 · HCJ091-121 · DCJ091-121
• Certificate: CE + UL + UKCA · EU RoHS compliant
• Net weight: 290 g
• Danfoss packaging: Multipack 6 (catalog information; this listing is sold as a single unit)

Other Voltage Options for the Same Compressor Group

Technician's Tips

• Mounting location is critical: the heater is wrapped around the lower partof the compressor, where the oil collects. A heater wrapped higher up does not heat the oil and wastes energy.
• Full contact is essential: the belt must rest against the body along its entire length. Where there is a gap, the heater overheats itself and burns out. The clamp screw is tightened to a maximum of 2 Nm; overtightening crushes the belt.
• Not self-regulating: belt heaters are not self-regulating and must be controlled externally. The correct connection energizes it when the compressor STOPS (via the contactor's auxiliary contact).
• Target: the crankcase oil should be kept about 10 K above the refrigerant's saturated low-pressure temperature.
• Outdoors: below −5 °C and in winds above 5 m/s, additional thermal insulation of the compressor is recommended; otherwise the heater alone cannot keep up.
• Check: the resistance of a healthy 65 W / 230 V heater should be about 814 Ω (calculated as 230² ÷ 65). If the measurement shows an open circuit, the heating element is broken.
• A different compressor? For MLZ/MLM 015-026 use the 60 W / 240 V 120Z0895; for SM/SZ 084-161 scroll compressors use the 65 W / 230 V 7773107.