Direct level detection
Detects when coolant or conductive water is no longer touching the installed probe.
Australian Made Since 1978 Quality Reliability Local Support
Bolec WL601 Low Water Level Alarm Kit 7sec Delay 12/24VDC
$205.00
Kit Includes:
- WL601P Low Water Level Probe (Push On)
- 4 Way plug
- 4 x brass terminals
- Instruction manual
Product resources
Key benefits
- Detects coolant or conductive-water loss directly
- Approx. 7-second delay helps reduce false alarms
- Suitable for 12V and 24V negative-ground systems
- Complete kit supplied with one WL601P probe
Need a spare or replacement WL601P probe?
The complete WL601 kit already includes one probe. Add another only as a spare, replacement or additional sensing point.
View additional WL601P probe BOLEC Product catalogue / Installation overview
Low coolant early warning
WL601
Low Water Level Alarm Kit - 12/24 VDC
- 12/24 VDC
- Approx. 7 s delay
- 1.5 A ground output
- AC coolant sensing
bolec.com.au | sales@bolec.com.au | 0480 312 400
WL601 technical overview
Detect coolant loss before a temperature gauge may respond
The WL601 monitors whether coolant is touching the radiator probe. When the level falls below the probe for approximately seven seconds, the normally-open alarm output switches to ground.
- Direct coolant or water-loss detection
- Approx. 7-second anti-slosh delay
- 12V and 24V operation
- Complete kit supplied with one WL601P probe
A4 catalogue layout - print or choose "Save as PDF".
Protection principle
Essential protection without unnecessary complexity
The WL601 monitors coolant contact directly and provides a delayed alarm output. Technical details, wiring and installation guidance are available in the sections below.
Approx. 7-second delay
Helps prevent nuisance alarms caused by brief fluid movement, bumps or cornering.
12V and 24V operation
Designed for common negative-ground vehicle, engine and industrial electrical systems.
Complete installation kit
Includes the WL601 module, one WL601P probe, connector, terminals and installation information.
Published product data
Specifications
Use these values for initial planning. Confirm the supplied unit and current controlled instructions before final wiring or installation.
| Operating voltage | 12/24 V DC, negative ground |
|---|---|
| Alarm delay | Approximately 7 seconds after coolant falls below the probe |
| Alarm output | Normally-open output switching to ground |
| Output rating | 1.5 A resistive maximum at 12/24 V DC |
| Sensing method | AC sensing through coolant to reduce electrode plating |
| Module construction | Epoxy-filled ABS housing |
| Module dimensions | 58 x 42 x 29 mm |
| Standard probe | WL601P push-on probe with 9.5 x 16 mm rubber seal |
| Recommended probe position | Approximately 13 mm above the radiator core, or at the required safe minimum level |
The output is intended for a compatible low-current alarm load. Use an external relay when the connected load or shutdown device exceeds the module rating.
Connections
Four wiring functions
The connector provides power, ground, probe sensing and alarm output. Follow the markings on the supplied module for the physical terminal order.
Function A Switched positive supply Connect to fused +12/24 V DC that is active while the equipment operates.
Function B Negative / ground Connect to a clean chassis or battery-negative point with a reliable return path.
Function C Probe input Connect to the WL601P sensing probe installed at the selected low-coolant level.
Function D Alarm output Normally-open ground output, maximum 1.5 A resistive at 12/24 V DC.
Typical external relay arrangement
When the WL601 output must operate a larger buzzer, lamp, solenoid or shutdown device, use it to switch the coil of a correctly rated external relay.
- Fuse the positive supply close to its source.
- Confirm the relay-coil current is within the WL601 output rating.
- Fit suppression across inductive relay or solenoid coils where required.
- Size the relay contacts and wiring for the final load.
Do not identify terminals from this webpage alone Confirm the terminal markings on the supplied module or the current instruction
manual before applying power. Incorrect wiring can damage the module or vehicle wiring.
Installation
Probe and module installation
The standard installation uses a push-on probe in the radiator tank and a protected module location near the vehicle or engine electrical system.
Standard installation sequence
- Allow the engine and cooling system to cool fully. Isolate electrical power and remove pressure before working on the radiator.
- Choose a probe position approximately 13 mm above the radiator core, or at the minimum coolant level required for the application.
- For the standard WL601P push-on probe, prepare a clean 9.5 mm hole and remove all burrs that could damage the rubber seal.
- Fit the probe and compress the seal evenly. Do not overtighten or distort the radiator tank. Inspect carefully for leaks.
- Mount the WL601 near the fuse panel or another protected area, away from direct heat, water spray, abrasion and moving components.
- Connect fused switched power, ground, probe input and alarm output according to the supplied module markings and instruction manual.
- Refill and bleed the cooling system correctly, then inspect the probe seal and complete a functional alarm test before returning the equipment to service.
Radiator material and grounding
Conductive metal radiator or tank
Confirm the radiator or tank has a reliable electrical return path and that corrosion, sealants or mounting bushes do not interrupt the sensing circuit.
Plastic or electrically isolated tank
Do not assume a standard metal-tank installation will work. Contact Bolec or auto-electrical support before drilling so the sensing and grounding method can be confirmed for the specific radiator.
Mounting and wiring checks
- Use a suitable fuse in the positive supply.
- Keep wiring away from exhaust heat, belts, fans and sharp edges.
- Use a clean and reliable negative / ground connection.
- Keep the probe wire away from ignition leads and high-current switching cables.
- Support the wiring so vibration is not transferred to the probe terminal.
- Check the cooling system for leaks after the engine reaches operating temperature.
Cooling-system work can be hazardous Never open or drill a hot, pressurised cooling system. Installation should be
completed by a competent mechanic or auto electrician when the radiator design,
alarm circuit or shutdown interface is uncertain.
Commissioning
Functional testing and troubleshooting
Test the warning system after installation and during scheduled maintenance. Do not rely on an untested alarm for engine protection.
Basic alarm test
- Make the vehicle or equipment safe and keep the engine stopped unless the controlled instructions require otherwise.
- Switch on the WL601 supply and confirm the alarm is not active with the probe correctly immersed.
- Simulate loss of probe contact using the method permitted by the current instruction manual.
- Confirm the alarm output operates after approximately seven seconds.
- Restore the sensing connection and confirm the alarm circuit returns to normal.
- Inspect all wiring and the probe seal before returning the equipment to service.
No alarm after loss of probe contact
- Confirm switched 12/24 V DC power and negative / ground at the module.
- Confirm the delay period has elapsed.
- Check the probe lead and alarm-output wiring against the module markings.
- Check the warning lamp, buzzer or external relay independently.
- Confirm the alarm load and relay-coil current do not exceed the output rating.
Intermittent or nuisance alarms
- Confirm the coolant level is not already close to the probe height.
- Inspect the probe terminal, ground connection and connector for corrosion or looseness.
- Check for trapped air or incorrect cooling-system bleeding.
- Route the probe wire away from ignition and high-current switching wiring.
- Confirm the radiator material and electrical return path are suitable for the installation method.
Documents and help
Downloads and technical support
Keep the current controlled instructions available when drilling, wiring, commissioning or troubleshooting the installation.
WL601 specification sheet Open the public WL601 specification PDF in a new tab. Request the instruction manual Email Bolec for the latest controlled installation instructions. Application support Ask about probe mounting, radiator compatibility or an external relay.
Web technical content is an installation overview. The controlled Bolec document and markings on the supplied product take precedence if any difference is found.
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Application guides
Related guides
Read more about coolant-level detection, probe installation and engine protection.
