Siemens QAD22 strap-on pipe temperature sensor, LG-Ni1000, -30…+130 °C, DN15…140
- Type: LG-Ni1000 (1000 Ω at 0 °C)
- Measuring range: -30…+130 °C
- Time constant: ~3 s
- Pipe size: DN15…DN140 (metal strap included)
Where QAD22 is used
QAD22 measures water or glycol temperature on the pipe surface — with no need to cut into the system. Used when a fast response is required or when installing an immersion sensor is impractical (retrofit, insulated pipework, plate heat exchanger connections). Typical applications: building heating/cooling flow and return lines, plate heat exchanger secondary outlet, pump groups.
Works with Siemens Synco, RVD, RVA, RVL, Climatix, and Desigo controllers — the LG-Ni1000 signal is accepted directly, no adapter needed.
Technical specifications
| Parameter | Value |
|---|---|
| Model | Siemens QAD22 |
| Sensing element | LG-Ni1000 (1000 Ω at 0 °C) |
| Measuring range | -30…+130 °C |
| Accuracy | ±0.4 K at 0 °C (element), +Δ from surface contact |
| Time constant | ~3 s (fast response) |
| Connection | 2-wire, non-polarised |
| Pipe diameter range | DN15…DN140 (metal strap included) |
| IP class | IP42 |
| Ambient temperature | -30…+130 °C |
| Dimensions (W × H × D) | 60 × 67 × 43 mm |
| Housing material | Polycarbonate / ABS |
| Mounting | Strap-on to pipe |
When to choose QAD22
- System retrofits where cutting the pipe for an immersion sensor is impractical
- Plate heat exchanger secondary flow/return signal for the heating curve
- Pump group flow-line limit signal
- Fast response applications (~3 s) — dynamic control, rapidly changing flow
- Compatibility: Siemens controllers with LG-Ni1000 input — Synco 100/200/700, RVD1xx/2xx, RVA/RVL, Climatix POL6xx/8xx, Desigo. Not compatible directly with Pt1000 controllers (Danfoss ECL) or NTC10 controllers (Ouman).
B2B delivery and logistics via Amegata.lt
- 24-hour delivery across Lithuania (from our warehouse in Vilnius)
- Competitive B2B pricing — often below market average
- 30-day payment terms for companies (per contract)
- Free technical consultation on sensor selection (strap-on vs immersion)
Official Siemens catalogue: hit.sbt.siemens.com/QAD22
Frequently asked questions
When to choose strap-on (QAD22) vs immersion (QAE)?
QAD22 (strap-on) — when the pipe must not be cut (retrofit), fast response needed (~3 s), measurement accuracy is non-critical (±1-2 °C acceptable for heating curve). QAE26.91 or similar (immersion) — when precision is required (heat metering, safety limits) or measurements up to 180 °C.
Is insulating the sensor zone mandatory?
Yes. Without insulation the strap-on sensor is exposed to ambient air — readings can drift by 5-10 °C. Insulation must fully wrap the sensor and extend 10-15 cm along the pipe on both sides.
Is it suitable for plastic pipes?
Technically possible, but heat transfer through plastic is significantly slower — the effective time constant grows several times, precision suffers. Recommended only for metal pipes (steel, copper, stainless steel).
Can QAD22 replace Danfoss ESM-11 or Ouman TMS?
Not directly. Different sensing elements: Danfoss ESM-11 — Pt1000, Ouman TMS — NTC10, QAD22 — LG-Ni1000. Each is designed for its own controller family. Mixing produces wrong readings.
How to extend the cable?
Use 2-wire shielded cable (2 × 0.75 mm² LiYCY). Practical limit ~100 m. Ground the shield only at the controller end.
