Three Hidden Costs in Temperature Monitoring at Heat Exchange Stations During the 2026 Heating Season
▲ Schematic diagram of three hidden costs in temperature measurement at heat exchange stations and the configuration of paired Temperature Sensors
As the 2026 heating season approaches, the selection of temperature measurement systems for heat exchange stations is often treated as a "trivial matter" —after all, it's just a PT100 sensor; what could possibly be so critical? Yet, what truly poses challenges for heating utilities when conducting year-end financial reviews are the hidden costs: discrepancies in heat settlement accounts, fluctuating secondary network water supply temperatures, and the need to replace Temperature Sensors every six months. The root cause of these three issues often points to the same factor: the selection and installation of Temperature Sensors at heat exchange stations.
01. Why are temperature measurement issues common at heat exchange stations?
The temperature measurement environment at heat exchange stations exhibits three key characteristics: high water temperatures within the pipelines (up to 130 °C in the primary network), a small temperature difference between the supply and return water (typically only 10–15 °C in the secondary network of energy-efficient buildings), and strong electromagnetic interference (due to the high density of variable-frequency pumps and motors).
What does a small temperature difference imply? It means that the error directions of the two supply and return water sensors must be highly consistent. Heat calculation relies on the enthalpy difference, which in turn derives from the temperature difference between the supply and return water. If the errors of the two sensors are of opposite signs—one positive and one negative—the errors will add up rather than cancel each other out; even if the individual sensors possess high precision, this situation cannot be rectified.
Consider a practical example: under standard operating conditions with a supply temperature of 80 °C and a return water temperature of 60 °C, the temperature difference is 20 °C. If the supply water sensor reads 2 °C higher than the actual value, and the return water sensor reads 1 °C higher than the actual value, the calculated temperature difference will be inflated by 1 °C, resulting in a relative error of 5%.
Comparison Table of Temperature Measurement Accuracy Grades for Heat Exchange Stations
| Configuration Plan | Single-unit tolerance (80 °C) | Pairwise temperature difference | Applicable Standards | Heat meter matching rating |
|---|---|---|---|---|
| Class A paired PT1000 | ±0.31℃ | ≤0.1℃ | IEC 60751 / CJ128 | Class 1 heat meter |
| Class A single PT1000 | ±0.31℃ | Not calibrated | IEC 60751 | Monitoring only |
| Class B paired PT1000 | ±0.70℃ | ≤0.3℃ | IEC 60751 | Class 2 heat meter |
| Standard Class B PT100 | ±0.70℃ | Uncontrolled | IEC 60751 | Not recommended |
Key point: Paired temperature sensors must be of the same model, same accuracy class, and same calibration batch, and must be factory-bound with a unique pairing code. When replacing sensors, you must never replace only a single unit—since the drift characteristics of new and used components differ, the pairing error will immediately worsen.
02. Inaccurate water supply temperature control
If there is a systematic temperature measurement deviation of ±0.5 °C, the controller will continuously set the operating temperature 0.5 °C higher than the actual temperature. An even greater challenge lies in the installation position of the probe. During pipeline temperature measurement, the temperature-sensing section must be fully immersed within the fluid flow zone, and the probe should be inserted to half the inner diameter of the pipeline.
03. The probe replacement cycle
Water quality at heat exchange stations is the primary factor compromising sensor lifespan. Once a sensor fails, the consequences extend beyond the cost of the replacement components—these include system downtime, water drainage, disassembly and reassembly, and re-insulation.
| Verification Items | Correct approach | frequent fault |
|---|---|---|
| Sensor Type | Mandatory matching | Mixed use of PT100/Pt500/NTC |
| Accuracy class | Completely identical | Mixing of new and existing |
| Calibration | Factory-issued pairing code | Self-assembly |
| Depth | Midpoint of pipe diameter | Too shallow |
Do these two things before the heating season:
First, conduct a paired temperature difference verification before the heating season. Place both the supply and return water sensors simultaneously into a portable constant-temperature bath.
Second, inspect the insertion depth of the inspection probe and the insulation of the casing. Neither of these items requires additional procurement; a single on-site inspection can directly prevent the waste of gas.
Weilianfengran Sensing Technology provides dedicated paired PT1000 temperature sensors for heat exchange stations, featuring Class A accuracy, a paired temperature difference of ≤0.1 °C, and protection sleeves made of 304/316L stainless steel. The sensors are factory-calibrated, accompanied by test reports, and support customization of probe length and thread specifications. Please contact us for a tailored selection solution.