Brand: JUMO

JUMO exTHERM-AT Explosion-Proof Surface-Mounted Thermostat

Name: JUMO exTHERM-AT Ex Thermostat 605055 | Seven Star LLC
Brand: JUMO
SKU: exTHERM-AT

Description

Ex-protected thermostat for gas and dust zones with TW, STW and STB versions

The JUMO exTHERM-AT (type 605055) is an explosion-proof surface-mounted thermostat that monitors and controls temperatures in potentially explosive areas. It may be used in gas and steam atmospheres (zones 1 and 2) and in areas with conductive dust (zones 21 and 22). A thermowell for use in zone 0 is available as an accessory.

It is offered as a temperature monitor (TW), a safety temperature monitor (STW) and a safety temperature limiter (STB), according to DIN EN 14597, and as a double thermostat that combines two functions in one housing. The thermostats work on the liquid expansion or gas expansion principle, and the electrical element is a pressure-resistant encapsulated thermostat with a snap-action switch.

Standard ambient temperature compensation keeps switching points stable when the temperature around the head and capillary fluctuates. The series is RoHS conform and cadmium free, and Push-In terminal technology gives a quick and safer electrical connection.

Approvals listed in the data sheet include ATEX and UKEX from Bureau Veritas, IECEx on request through extra code 372, PESO for India (083), CCC-Ex for China (084), KC Korea KOSHA and UA TR. Certificates for approved device versions can be downloaded from the manufacturer website.

Technical specifications

Parameter	Specification
Type	605055; TW (0002), STW (0020), STB (0070), TW/STB (0270), STW/STB (2070)
Ex marking (gas)	ATEX II 2G Ex db eb IIC T4/T5/T6 Gb; IECEx Ex db eb IIC T4/T5/T6 Gb
Ex marking (dust)	II 2D Ex tb IIIC T85 °C/T100 °C/T130 °C Db
Certificates	ATEX EPS 11 ATEX 1 354; UKEX EPS 22 UKEX 1 129; IECEx EPS 13.0046 (extra code 372); SIL 2 (extra code 073)
Control ranges	-20 to +40, -20 to +50, 0 to 120, 20 to 400, 0 to 190, 60 to 300, 70 to 190, 130 to 190, 140 to 500, 150 to 300 °C
Switching capacity	AC 230 V 16(2.5) A or 25(4) A, AC 400 V 16 A, or AC/DC 24 V 0.1 A on the N/C contact
Switching differential	None, about 2.5 % or about 7 %, selectable
Ambient temperature	-55 to +70 °C (standard -40 to +70 °C); T6 to +40 °C, T4 to +70 °C; T4 to +55 °C at 25 A
Housing	Glass-fiber reinforced polyester, black, conductive surface; stainless steel optional
Protection type	IP65; IP66 with extra code 861
Cable entries	Ex cable gland M20 x 1.5 (6 to 13 mm) and M25 x 1.5 (7 to 17 mm)
Process connection	Plain cylindrical probe, spiral probe (room version) or mounting adaptor for thermowell; capillary 0, 1000 or 3000 mm in CrNi
Weight	Approx. 1200 g single and 2000 g double thermostat

Selecting the thermostat function

A temperature monitor (TW) opens or closes the microswitch when the probe exceeds the setpoint and resets when the temperature falls by the switching differential. A safety temperature limiter (STB) opens the circuit at the limit value and mechanically locks it, and it can be unlocked by hand only after the temperature has dropped by about 20 percent of the scale range.

The STW and STB also monitor themselves: if the measuring system is destroyed and the expansion fluid escapes, the pressure in the membrane falls and the circuit opens permanently, with no unlocking possible. The STW unlocks itself automatically. The maximum permitted probe temperature is stated as 15 percent above the limit or maximum adjustment value, or 25 K above it.

Single and double versions are possible. A double thermostat can combine, for example, a control thermostat with a safety limiter in the same housing, using probes of 4 or 6 mm and capillary lengths of 1000 or 3000 mm.

The order code covers the housing (polyester or stainless steel), the control range for each thermostat, the switching capacity, the admissible ambient temperature at the housing (code 340 for -55 to +40 °C at T6, code 467 for -40 to +40 °C at T6) and the capillary and probe dimensions. An example is 605055/0020-5-4-195-000-21-467-70-00-1000-0-20-10-6-0-0/000.

Stock versions listed in the sheet include 605055/0020-5-4-195-000-21-467-70-00-1000-0-20-10-6-0-0/000 for 0 to 190 °C with a 1000 mm capillary and 6 mm probe, and other versions for -20 to +50 °C and 60 to 300 °C. Ask us to confirm the current availability of the code you need.

Installation and accessories

The setpoint is adjusted with a screwdriver after removing the case lid, and the head is fastened with four screws. Rated position follows DIN 16257 from NL 0 to NL 90. A switching point offset occurs when the ambient temperature at the head or capillary differs from the calibration temperature of 22 °C: a higher ambient gives a lower switching point.

Multi-section standard thermowells in CrNi for zones 1, 2, 21 and 22 are described in data sheet 606710, and thermowells for zone separation 0/1 and 20/21 are described in data sheet 605057. Confirm the zone, temperature class and approval extra code for your site and country before ordering.

Because the dust zones require a conductive housing surface, the polyester case is soot-doped so that static charging is not possible. The stainless steel case is the choice for harsh washdown or corrosive surroundings.

Documents and quotation

For engineering details, open the attached PDF (JUMO exTHERM-AT data sheet 605055 (EN, 14 pages)). When you are ready to buy, submit the order code and project requirements through the request form, and our team will confirm what can be supplied and when. Browse the category Temperature Instrumentation for alternatives.

Datasheets & Documents

Datasheet JUMO exTHERM-AT data sheet 605055 (EN, 14 pages) Download

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About brand

JUMO is the German maker of temperature sensors, process controllers, pressure transmitters and liquid analysis instruments. Moritz Kurt Juchheim founded it in Fulda in 1948 as M. K. Juchheim KG, making glass thermometers with six employees. The name JUMO comes from the founder's name. It is still a family company headquartered in Fulda, and the parent company has been called JUMO GmbH & Co. KG since 2003.

Seven Star LLC is an independent supplier in Muscat. We list JUMO RTD and thermocouple probes, thermowells, transmitters, controllers, recorders and water analysis instruments, and supply them to process plants, OEMs, HVAC contractors and water utilities in Oman and the GCC by type number.

JUMO company profile

Established	1948, Fulda, Germany, by Moritz Kurt Juchheim
First products	Glass and contact thermometers; platinum glass sensors from 1966
Ownership	Family-owned; renamed JUMO GmbH & Co. KG in 2003
Product families	RTD and thermocouple probes, thermowells, temperature and pressure transmitters, controllers and thermostats, safety temperature limiters, paperless recorders, liquid analysis and flow and level instruments

Milestones

1948: Moritz Kurt Juchheim founds M. K. Juchheim KG in Fulda, making glass thermometers with six employees.
1966: Platinum glass temperature sensors are added.
2003: The parent company is renamed JUMO GmbH & Co. KG.

JUMO products we list

Family	Models	Typical use
RTD and thermocouple probes	902020, 902030, 902050, 902120, 902006 2xPt100, PROCESStemp, mineral-insulated RTD, 901020 thermocouple, 901210, 902810 hygienic, 902550 surface, 902520 HVAC, MarineTemp	Temperature measurement in pipes, vessels, machines, HVAC and food plants
Thermowells and inserts	909710 thermowells, 909740 measuring inserts	Protecting sensors and replacing them without opening the process
Temperature transmitters	dTRANS T01, T03, T04, T05, T06 SIL, T07 HART, T09, T1000 IO-Link, DELOS T switch	Converting sensor signals to 4-20 mA, HART or IO-Link
Pressure and level	dTRANS p20, p30, p31 hygienic, p33 Ex, p02 DELTA, MIDAS S05, MIDAS DP10, DELOS S02, MAERA S25, NESOS R20	Pressure in process, hydraulic and OEM systems; tank and well level
Controllers, limiters and recorders	DICON touch, IMAGO 500, dTRON 316, iTRON, cTRON, diraTRON 104, eTRON T, safetyM STB/STW, safetyM TB/TW, LOGOSCREEN 601, mTRON T	Furnace, oven and process control, over-temperature protection and recording
Liquid analysis and flow	AQUIS touch S, AQUIS touch P, AQUIS 500 pH, AQUIS 500 CR, dTRANS pH 02, pH electrode, digiLine DO, ecoLine NTU, flowTRANS MAG H20, flowTRANS US W01	pH, conductivity, oxygen and turbidity in water treatment; liquid flow

Choosing a temperature sensor starts with the range and accuracy. A Pt100 RTD is accurate and stable from about -200 to 600 °C and is the usual choice in process plants. A thermocouple (type K or J, for example) covers much higher temperatures and responds faster but is less accurate. The wiring also matters: a 3-wire or 4-wire Pt100 connection cancels the resistance of the cable, while a 2-wire connection adds an error that grows with cable length. That is why a head-mounted transmitter is often fitted close to the sensor.

Where JUMO products are used

In Oman and the GCC, JUMO sensors and controllers are used in oil and gas and chemical plants, food and beverage production, plastics and metal heat treatment, HVAC and district cooling, water and wastewater treatment, swimming pools and marine applications.

Ordering JUMO products: what we need

Send the JUMO type number and the full order code from the label (for example 902020/10-...). For probes, add the sensor type (Pt100, Pt1000, type K or J), the number of wires, the insertion length and diameter, and the process connection. For controllers, add the input, outputs and supply voltage.

Facts checked against JUMO's company history, October 2026.

Browse JUMO products by category: Temperature Instrumentation, Pressure Instrumentation, Liquid Analysis Sensors, Controllers & Data Acquisition, Level Transmitter.