HNF10-G Thermal Flow Switch with 6-LED Bar, Waterproof IP67

HNF10-G Thermal Flow Switch with 6-LED Bar, Waterproof IP67

Waterproof digital thermal flow switch with 6-LED bar. Anti-scaling conical probe, PNP/NPN/relay/SPDT, DC 24 V or AC, M12, IP67, for water, oil and air.

HNF10-G Waterproof Thermal Flow Switch with 6-LED Bar

The HNF10-G is a waterproof digital thermal flow switch built around an MCU core, with a 6-LED bar that displays flow status in real time. Its exclusive conical probe prevents fibrous media from wrapping around the sensor, and an anti-scaling coating stops lime and rust deposits from building up, keeping readings stable over long service. A unique waterproof adjustment knob lets the switch point be changed at any time without removing sealing screws or opening the housing. It works on both gas and liquid, with setting ranges for water, oil and air.

INQUIRY

Flow Monitoring for Water, Oil and Air

The switch monitors rising or falling velocity, medium present or absent, and flowing or static condition, and protects pumps from dry run. It is used on circulating water, cutting fluids and lubricating oil, in pneumatic and hydraulic systems, across petrochemical, power, metallurgy, steel, papermaking, food processing, water treatment and battery plants.

Good fit: petrochemical, electric power, metallurgy and steel plants, papermaking, food processing, water treatment, battery plants, pneumatic and hydraulic systems, circulating water, cutting fluid, lubricating oil dry-run monitoring, pump idling protection, cooling circuits, anti-scaling water systems.

Is HNF10-G Suitable for Your Application?

Choose HNF10-G when:

You need a no-moving-parts flow switch to monitor flow/no-flow, low/high velocity or pump dry run.
A visible 6-LED flow indicator and field setpoint adjustment without opening the sealed housing are required.
The medium is water, oil or air, with a choice of PNP, NPN, relay or SPDT output and DC or AC supply.

Confirm with us first when: the medium is highly corrosive (choose the coated probe material), the process pressure exceeds 100 bar, the medium temperature falls outside −20…90 ℃, or the required probe length or thread is non-standard.

Working Principle

Inside the sealed probe are two digital temperature sensors: one is heated as the measuring sensor, the other unheated as reference. When the medium flows, heat is carried away from the heated resistor and its temperature changes; the difference between the two sensors is used as the basis for judging velocity. The MCU reads the two temperature signals in real time through the hardware circuit, computes current velocity and switches the relay according to the set action parameters. Software temperature compensation keeps flow values stable across wider temperature ranges. The anti-scaling coating resists lime, rust and other deposits, and there are no moving parts to maintain.

Technical Specifications

Model	HNF10-G — Digital thermal flow switch, gas & liquid
Principle	Thermal differential: heated measuring sensor + unheated reference sensor, MCU processing
Setting range	Water 1–150 cm/s; oil 3–300 cm/s; air 20–2000 cm/s
Response time	1–10 s, typical 2 s; initialization time about 4 s
Output signal	PNP, NPN, relay, or SPDT (NO+NC)
Supply voltage	DC 24 V ±20 %; AC 110 V; AC 230 V
Switching current	Max 400 mA (PNP/NPN type); max 1 A, 48 V AC/DC (relay type); no-load current max 80 mA
Electrical protection	Reverse polarity, short-circuit and overload protection
Protection rating	IP67
Medium temperature	−20…90 ℃; medium temperature change ≤4 ℃/s
Ambient / storage temperature	Ambient −20…80 ℃; storage −20…100 ℃
Repeatability	±1 %
Pressure rating	100 bar standard; anti-corrosion type up to 200 bar on request
Materials	Probe: 304 / 316L / titanium / PTFE (custom); housing: stainless steel 304
Connection	M12 connector or direct cable; potentiometer setpoint; 6-LED flow indication

Selection Code

Code segment	Code	Description
Thread connection	G12	G1/2 thread
	G14	G1/4 thread
	G34	G3/4 thread
	G38	G3/8 thread
	N	Internal thread M18×1.5
	AL	Sanitary type with blind flange (316L)
	F / F1	Stainless steel flange, single F / double F1
	H	External thread
	S	Special thread, custom
Supply	D	DC 24 V ±20 %
	Y	AC 110 V
	W	AC 230 V
Output	P	PNP output
	N	NPN output
	C	Relay output
	R	NO+NC output (SPDT)
Connector / cable	Q	Connector type
	T	Direct cable
	2	Cable 2 m (optional 5 / 10 m)
	ZL04 / ZL05	M12 4-pin / 5-pin connector
	02 / 05 / 10	2 / 5 / 10 m cable length
	F / G / W	Female plug / straight plug / elbow plug
	K	Probe length custom, 15–80 mm
Probe material	—	304 / 316L / titanium / PTFE (custom)

Wiring

Wiring follows the selected output type: PNP, NPN or relay/SPDT. The M12 connector version uses ZL04 4-pin or ZL05 5-pin; the direct-cable version is supplied in 2, 5 or 10 m. Refer to the wiring diagram in the datasheet for the pin assignment of the chosen output before installation.

Installation and Setpoint Adjustment

When mounted horizontally, the probe should avoid trapped air and settled sediment.
Fit the switch and let the medium flow at the velocity to be monitored; adjust the potentiometer until the first green LED lights.
When velocity drops below this value, the switch releases. For a lower switch point, turn the potentiometer to light more green LEDs.
Keep the waterproof knob sealed after adjustment; do not remove the sealing screws to reposition the setpoint.

Typical Applications

Water systems: circulating water, cooling circuits, water treatment and supply.
Machinery lubrication: cutting fluid and lubricating oil monitoring, pump idle and dry-run protection.
Process industries: petrochemical, power, metallurgy and steel, papermaking, food processing, battery plants.
Gas service: pneumatic systems and compressed-air flow monitoring.

What to Send Us for Selection

Send: medium (water / oil / air), expected velocity range, pipe size and required thread or flange, output type (PNP / NPN / relay / SPDT), supply voltage, probe material, process pressure and temperature, and cable length or connector style. We will confirm the selection code before quoting.

Frequently Asked Questions

How does the conical probe resist fiber buildup?

The exclusive conical probe shape sheds fibrous material instead of letting it wrap around the sensor; together with the anti-scaling coating, it resists lime, rust and sticky deposits that would otherwise shift the reading.

Can the switch operate from AC mains power?

Yes. Besides DC 24 V ±20 %, AC 110 V and AC 230 V supply versions are available; choose the supply code D, Y or W in the selection table.

Which probe material handles corrosive media?

The probe can be 304, 316L, titanium or PTFE for corrosive service. Send the chemical and concentration so we can match the material; the anti-corrosion type can reach up to 200 bar on request.

Does the waterproof knob allow setpoint adjustment without opening the sealed housing?

Yes. The dedicated waterproof adjustment knob changes the switch point without removing sealing screws or opening the housing, so the IP67 seal stays intact during field setup.

What response time can be configured for water, oil or air monitoring?

Response time is 1–10 s, typical 2 s, with about 4 s initialization. The setting ranges are 1–150 cm/s for water, 3–300 cm/s for oil and 20–2000 cm/s for air.