Technical Specifications
WaterFlow Sensors
Sensor Overview
| Model | Temp | Thread | DN | Material Options | Accuracy | Flow Range | Typical Use |
|---|---|---|---|---|---|---|---|
| YF-B1 | ❌ | G1/2" | DN15 | Brass or Stainless Steel | ±3% | 1 to 25 L/min | Standard household pipes |
| YF-B7 | ✅ | G1/2" | DN15 | Brass only | ±3% | 1 to 25 L/min | Standard household pipes |
| YF-B5 | ❌ | G3/4" | DN20 | Brass or Stainless Steel | ±3% | 1 to 30 L/min | Boilers, garden irrigation |
| YF-B6 | ✅ | G3/4" | DN20 | Brass only | ±3% | 1 to 30 L/min | Boilers, garden irrigation |
| YF-B10 | ❌ | G1" | DN25 | Brass or Stainless Steel | ±5% | 1 to 50 L/min | Main water lines, heat pumps |
| YF-DN40-S | ❌ | G1½" | DN40 | Stainless Steel only | ±3% | 5 to 150 L/min | Pool systems, industrial |
| YF-DN50-S | ❌ | G2" | DN50 | Stainless Steel only | ±3% | 10 to 200 L/min | Large pipes, high flow, industrial |
Note: The mm size is an indication; actual pipe diameter may vary due to pipe wall thickness.
Pulse Frequency Formulas
| Model | Formula | Approx. Pulses/Liter |
|---|---|---|
| YF-B1, YF-B7 | F ≈ 11 × Q | ~660 pulses/L |
| YF-B5, YF-B6 | F ≈ 6.6 × Q | ~396 pulses/L |
| YF-B10 | F ≈ 7.5 × Q − 3 | ~450 pulses/L |
| YF-DN40-S | F ≈ 0.45 × Q | ~27 pulses/L |
| YF-DN50-S | F ≈ 0.20 × Q | ~12 pulses/L |
F = frequency in Hz, Q = flow rate in L/min
Sensor Materials
Most of our sensors are available in Brass or Stainless Steel. Choose based on your application:
Brass (Messing)
Available for: YF-B1, YF-B5, YF-B6, YF-B7, YF-B10
- ✅ Sturdy and affordable
- ✅ Suitable for most household applications
- ✅ Good corrosion resistance
- ✅ Lower cost option
Best for: Standard home use, hot/cold water lines, heating systems, general plumbing
Stainless Steel (RVS)
Available for: YF-B1, YF-B5, YF-B10, YF-DN40-S, YF-DN50-S
- ✅ Food-safe and hygienic
- ✅ Superior durability and corrosion resistance
- ✅ Recommended for drinking water applications
- ✅ Longer lifespan in demanding conditions
Best for: Drinking water systems, food/beverage applications, pools, industrial, situations requiring extra hygiene or durability
💡 Tip: For most household applications (kitchen, bathroom, heating), Brass sensors are perfectly suitable and more affordable. Choose Stainless Steel when hygiene, durability, or food-safety is important.
Choosing the Right Sensor
By Pipe Size
| Your Pipe | Recommended Sensor | With Temperature |
|---|---|---|
| ~15mm (½") | YF-B1 or YF-B7 | YF-B7 |
| ~20mm (¾") | YF-B5 or YF-B6 | YF-B6 |
| ~25mm (1") | YF-B10 | ❌ Not available |
| ~40mm (1½") | YF-DN40-S | ❌ Not available |
| ~50mm (2") | YF-DN50-S | ❌ Not available |
By Application
| Application | Recommended Sensor |
|---|---|
| Kitchen faucet | YF-B1 / YF-B7 (G1/2") |
| Bathroom / Shower | YF-B1 / YF-B7 (G1/2") |
| Toilet | YF-B1 / YF-B7 (G1/2") |
| Boiler / Water heater | YF-B5 / YF-B6 (G3/4") |
| Garden irrigation | YF-B5 / YF-B6 (G3/4") |
| Heat pump (supply/return) | YF-B10 (G1") |
| Main water line | YF-B10 (G1") |
| Swimming pool system | YF-DN40-S (G1½") |
| Industrial / High flow | YF-DN50-S (G2") |
Heat Pump Monitoring
A popular use case is monitoring heat pump circuits:
- Use 2x YF-B10 sensors on the G1" supply and return lines
- Measure both flow rate and temperature (with YF-B6 on G3/4" if available)
- Calculate heat output by combining flow and temperature differential
Water Temperature Measurement
Available on YF-B7 and YF-B6 models only.
- Measurement Range: 0°C to +80°C
- Accuracy: ±0.5°C
- Sensor Type: NTC thermistor (integrated in flow sensor)
Network Connection
V1
- Wi-Fi IEEE 802.11 b/g/n (2.4 GHz)
- Supports WPA2 and WPA3 security
- Captive portal onboarding
- Improv BLE and Improv Serial provisioning
V2
- Wi-Fi IEEE 802.11 b/g/n (2.4 GHz)
- Ethernet (RJ45)
- PoE support on V2 hardware
- Thread with the Thread firmware and a Thread border router
- Supports WPA2 and WPA3 security on WiFi
- Captive portal onboarding
- Improv BLE and Improv Serial provisioning on WiFi firmware
5 GHz networks are not supported.
Physical Dimensions
Main Unit (WaterFlowKit):
- 92 × 47.5 × 26.5 mm
Cable Length
- USB-C power cable: 3 meters (if selected at checkout)
- Sensor cable: 1 meter per sensor
Note: Sensor cables have connectors on both ends, so you can easily click them in and out on both the WaterFlowKit and the sensor side.
Power Supply
V1
- USB-C power input
- 5V / 1A
V2
- USB-C power input
- 5V / 1A
- PoE possible on V2 hardware
USB adapter is included if selected at checkout.
Protection Rating
| Component | IP Rating | Protection |
|---|---|---|
| Flow sensors | IP52 | Dust and light moisture (splashing) |
| Main unit | IP20 | Indoor use only |
⚠️ The main unit is not waterproof. Keep it dry at all times.
Operating Temperature
- Main unit: -10°C to +40°C
- Flow sensors: 0°C to +80°C (water temperature)
Software
- Firmware: OpenSource ESPHome
- Integration: Fully integrated with Home Assistant
- Updates: Over-the-air (OTA) firmware updates supported
- Source Code: GitHub - smarthomeshop/waterflowkit