Danfoss 017-501466 RT 3 Thermostat -25 to 15 C

Danfoss 017-501466 RT 3 thermostat, -25 to 15 °C with 2 m capillary

The Danfoss 017-501466 is an RT 3 thermostat for temperature control and protection between -25 and 15 °C. A cylindrical remote sensor of 9.5 mm diameter and 80 mm length is connected by a 2 m capillary to a bellows in the switch housing; the pressure of the vapour charge changes with the sensor temperature and drives an SPDT contact. The adjustable differential is 2.8 to 10 °C at the lowest range setting and 1 to 4 °C at the highest, and the sensor may see up to 150 °C without damage. Seven Star LLC supplies the 017-501466 in Oman and the GCC as an independent supplier in Muscat.

The same RT 3 is also made with 5 m (017-501666) and 8 m (017-501766) capillaries, which is the main thing to confirm when you replace an existing thermostat.

017-501466 type, charge and capillary

017-501466 technical specifications

How vapour-charge thermostats work

The sensor, capillary and bellows form a closed system containing a small amount of liquid. Only the liquid in the coldest part of the system evaporates, so the pressure in the bellows is the saturation pressure at the sensor temperature. This relationship makes the unit a pressure switch whose scale is calibrated in degrees. When the sensor is the coldest part of the system, the ambient temperature around the capillary and housing has no influence on accuracy, which is why the data sheet insists that the sensor of a type A thermostat must not be the warmest part. If the sensor is warmer than the housing, the vapour condenses in the bellows and the thermostat loses control.

On the scale, the knob sets the temperature at which the contact changes over on falling temperature, and the differential disc sets how far above it the temperature must rise to switch back. The data sheet notes that the mechanical differential is always smaller than the thermal differential seen by the process, which depends on flow velocity, charge rate of the medium and heat transmission, so choose a conservative setting and trim it after the plant has run.

Where the 017-501466 fits among RT thermostats

The RT 3 is a cold-range thermostat. Neighbours with remote sensors include the RT 9 (-45 to -15 °C), RT 13 (-30 to 0 °C), RT 2 (-25 to 15 °C with an adsorption charge, 017-500866), RT 14 (-5 to 30 °C) and RT 101 (25 to 90 °C, 017-150066). The RT 17 (017-152066) is a room-sensor type for even colder duty. If the application does not need -25 °C, the RT 14 gives a wider choice of capillary lengths from 2 to 10 m.

Selection and ordering checklist for RT 3

• Control or alarm temperature and differential, inside -25 to 15 °C.
• Capillary length: 2 m for this code, 5 or 8 m for the sister codes, measured from sensor position to the switch location.
• Sensor position, so that it is the coldest part of the system, and whether a sensor pocket or capillary gland from the accessory list is needed.
• Maximum temperature the sensor will meet during defrost, cleaning or upset, which must stay under 150 °C.
• Electrical load, voltage and contact sets, including manual-reset options listed separately.
• Marine class marks if relevant; this code lists GL and NKK.

Installation and commissioning

Fit the thermostat housing on a flat support using its two fixing holes, in any orientation unless a non-snap contact accessory is fitted, in which case the setting knob must be upwards. Place the sensor where it sees the true process temperature: in a pocket in the liquid line, in a brine tank, or in the air flow. Avoid kinking the capillary and coil any excess length neatly; do not cut it. After wiring the SPDT contact, check the cut-out temperature with a reference thermometer, since the dial is only an indication.

Applications of the 017-501466 in Oman and the GCC

Cold-store and chiller plant, brine circuits, refrigerated containers and process cooling at food, water and petrochemical sites use thermostats in this range. In hot ambient conditions the housing stays accurate as long as the sensor is the coldest component. Condensation on cold capillaries and in terminal boxes is common in humid coastal air, so keep the cover gasket sound and the cable glands tight.

RT 3 capillary versions

Information to send with an RFQ for 017-501466

• Code 017-501466 and quantity.
• Control or alarm temperature and the process medium.
• Sensor location and distance to the control cabinet.
• Electrical load and voltage.
• Approvals and sensor pocket needs.

Documents and quotation

The Danfoss RT thermostat data sheet is attached on this page, with ordering tables, sensor pocket notes and setting guidance.

Send the code 017-501466 and your temperature data and we will confirm availability and a quotation for Oman and the GCC.