JUMO 608425 Contact Dial Thermometer, Class 1

Dial thermometer with limit contacts for control and monitoring

The JUMO 608425 is a contact dial thermometer with an actual value display for temperature measurement, control and monitoring. It can be built into a panel or used as an add-on device, and the manufacturer states display ranges from -40 °C to +600 °C and accuracy class 1 according to DIN EN 13190.

A liquid-filled or gas-filled measuring system turns the temperature-dependent change in volume or pressure into a rotation of the pointer through a bourdon tube, without gears. The switching output is actuated by the rotation of the indicator shaft. The direct connection of the indicator to the measuring system makes the unit extremely warp resistant, and oscillations reach the pointer only to a limited degree.

The switching output can be built as a slow-action contact, a magnetic snap contact or an inductive contact. Slow-action and magnetic snap contacts are auxiliary current switches with a contact arm that moves with the pointer, while the inductive contact is a contact-free limit switch working as a proximity switch.

Display correction at the rear is not available on design types 01 and 20 with a 100 mm case. Dimension drawings show the round add-on cases with an offset fitting and the square built-in case with a panel cut-out of 105.5 mm or 165.5 mm for round cases.

Technical specifications

Switching outputs and options

Switching output codes 01 to 05 and 10 and 11 describe contact one and contact two as normally open or normally closed on rising temperature, and codes 30 and 31 are the inductive contacts with the control lug moving in or out. Choose the code that matches the safe state of your plant on rising temperature.

The data sheet recommends a minimum of 24 V and 20 mA for good switching reliability and suggests multifunctional measurement and control relays that improve reliability and reduce contact load. An OFF delay on those relays reduces unwanted switching by vibration in electromechanical limit contacts.

Ambient influence is 0.15 percent of the display range per kelvin on the case for liquid-filled systems and 0.05 percent for gas-filled, and 0.03 percent per kelvin per meter of capillary on liquid fill with no influence on gas fill.

The display range table shows the measuring range inside each display range with the tolerance, for example 0 to +120 °C with a measuring range of +20 to +100 °C and 2.0 K tolerance for the 0 to 500 °C range at 5.0 K. Select a range that places your working temperature in the measuring range so that the stated class applies.

Process connection codes include temperature probes with stepped, plane or no support tube and protection tubes with threads G 3/8, G 1/2 or G 3/4 in stainless steel or in brass with stainless probes. Insertion lengths of 50, 100, 150 and 200 mm are standard, with other lengths in 50 mm steps.

Typical uses

Contact dial thermometers are used where an operator needs a local reading and a switching point at the same instrument, for instance on heating circuits, process tanks, machine cooling and plant rooms. The 160 mm dial is easy to read from a distance, and the square panel version fits control panels.

For plants that need a certified safety function, use a dedicated safety temperature limiter instead of a contact thermometer and compare the specifications.

Electrical connection for the round case is through a junction box with a cable fitting for cables of 6.5 to 13 mm, and for the square device through screw terminals. Conductor cross-sections up to 2.5 mm2 can be connected, and the contact must be fused according to the load.

Documents and quotation

Download the data sheet (JUMO 608425 data sheet (EN, 6 pages)) from the attachment on this page. To request a quotation, give us the complete order code from the data sheet and your quantity, and we will come back with stock status and lead time. More products of this kind are collected in Temperature Instrumentation.