Temperature Measurement
Measurement, Monitoring and Leak Detection
Medium temperature is the leading variable in a data centre. Supply temperature sets how much heat a rack can absorb, the spread between supply and return shows how much of it is actually carried away. The category holds 69 items from Riegler, Wika and Fluidics equipment: Pt100 and Pt1000 resistance thermometers plus bimetal thermometers for local indication. The miniature TR33 with M12x1 connector and the compact TR36 are available with insertion lengths of 50, 100, 150 and 200 mm.
The Pt1000 versions output 4-20 mA and connect straight to the building management system without an intermediate transmitter. Pt100 probes with IP 69 protection and a G 1/4 or G 1/2 process connection cover -40 to +85 °C, vertical bimetal thermometers 0 to +120 °C in accuracy class 1. Wetted parts in 1.4571 and 1.4301 are unrestricted in a water-glycol loop. Where a probe has to be replaced while the plant runs, it belongs in a thermowell rather than directly in the medium.
Probe designs compared
| Design | Element | Signal | Insertion length | Connection |
|---|---|---|---|---|
| Miniature thermometer TR33 | Pt1000 | 4-20 mA | 50, 100, 150, 200 mm | M12x1 plug |
| Compact thermometer TR36 | Pt1000 | 4-20 mA | 50, 100, 150, 200 mm | terminal head |
| Resistance thermometer IP 69 | Pt100 | resistance output | up to 150 mm | G 1/4 or G 1/2, 1.4571 |
| Bimetal thermometer, vertical | bimetal coil | local indication | 100 mm | 1.4301, class 1 |
- supply and return temperature at the cooling manifold and the CDU
- spread across the heat exchanger between primary and secondary loop
- free cooling threshold at the dry cooler based on return temperature
- frost protection monitoring in the outdoor section of the glycol loop
- local indication at pump set and buffer tank without auxiliary power
