JUMO 902120 Push-In RTD Temperature Probe with Terminal Head Form B

A push-in Pt100 probe with replaceable insert and a form B head

The JUMO 902120 is a push-in RTD temperature probe with a DIN form B terminal head for temperatures from -50 to +600 degC (-200 degC with operating-temperature code 150). It uses a replaceable measuring insert, can be supplied as a single or double RTD, and is available with a transmitter built into the head. JUMO names air conditioning and refrigeration, heating systems, kiln and apparatus engineering and process technology as typical areas for measuring temperatures in liquids and gases.

The standard measuring insert is a Pt100 to DIN EN 60751, class B, in 2-wire circuit; Pt500 or Pt1000 versions are possible and 3-wire or 4-wire connection is optional. Two basic types exist: 902120/10 with a continuous sheath of 9, 11 or 15 mm and 902120/11 with a stepped sheath, 12 mm reduced to 9 mm. Because the sheath is pushed into a thermowell or process opening, the probe is mounted with a flange, a stop flange or a sheath screw connection, or is installed without any process connection.

Technical specifications

Ordering the 902120: sheath, length, process connection and transmitter

The order code runs basic type – operating temperature – measuring insert – tolerance class – sheath diameter – nominal length – process connection / extra codes, and the datasheet example is 902120/10 – 402 – 1001 – 1 – 9 – 410 – 663 / 000. Measuring insert 1001 is 1 x Pt100 in 3-wire, 1003 is 2-wire, 1011 is 4-wire, and 2001 and 2003 are the double elements. A nominal length can also be given in plain text in 50 mm steps. Process connection 254 is a G 1/2 sheath screw connection (15 mm sheath on /10), 663 and 665 are sheet steel flanges and 668 is the DIN 43734 stop flange.

The measuring range of a built-in transmitter is stated in plain text at order; programmable versions also need the output signal specified.

Mounting and head selection

The connection head tolerates ambient temperatures up to +100 degC, but the allowed range is reduced when a transmitter is fitted, as noted for data sheets 707010, 707030 and 707060. The BUZ and BUZH heads are alternatives to the standard form B, and the NS plastic head suits lighter-duty indoor use at IP54. The double-element versions give a second independent signal, for example one channel for control and one for a limit device.

Choose the nominal length so that the sensing tip reaches the middle of the pipe or vessel; the fitting length range for each nominal length is printed in the order table. Because the insert is replaceable, a drifting sensor can be exchanged without removing the sheath from the process, which is useful for chilled-water, air-handling and boiler circuits where downtime must be short. The same family is also made with form J heads and with screw-in fittings in other JUMO data sheets.

Stepped sheaths improve response because the tip is thinner than the shoulder: type 902120/11 steps 12 mm down to 9 mm, whereas type 902120/10 keeps a uniform 9, 11 or 15 mm diameter along its length. The 15 mm sheath is the only one that accepts the G 1/2 sheath screw connection on the continuous type, and the 15 mm stop flange follows DIN 43734 in gray cast iron. Ambient temperature at the head must stay within +100 degC for the aluminium heads and +130 degC for the plastic NS head, which makes the NS head a lighter choice for hot rooms with low humidity.

Documents and quotation

The JUMO data sheet 902120 (dated 2026-01-07) is attached. Seven Star LLC supplies JUMO probes from Muscat; send the full order code or the sheath, length, process connection and transmitter option so we can quote. Other probes are grouped under https://omansevenstar.com/product-category/sensors-transmitters/temperature/.