APOLLO 491-4597 Digital Grademeter Sensor for AP655F Asphalt Paving Grade Control Back in Stock

Contractors running the AP655F asphalt paver can now source the grade feedback element of the screed control loop as a standalone spare: the APOLLO 491-4597 digital grademeter sensor is available again from stock in single sets.

Why This Sensor Matters on a Paving Train

Automatic grade control only works as well as the signal feeding it. On the AP655F, the grademeter sensor reads the elevation reference and reports deviation to the machine computer, which then commands the hydraulic valves to raise or lower the screed. If the sensor drifts, the whole loop compensates in the wrong direction and the mat either climbs or falls away from the design profile.

That is why a spare sensor is worth keeping near a working spreader. Replacing the unit takes minutes once the machine is stopped, while waiting for a part to clear customs can idle a crew for days and leave a cold joint that has to be cut out and re-laid.

What the 491-4597 Brings to the Job

• Digital signal output: digital processing ignores the electrical noise generated by the engine, hydraulic pumps and generator, cutting false corrections.
• Finer resolution: the sensor resolves smaller height changes, which supports tighter longitudinal evenness on long runs.
• Matched interface: the electrical connector and mounting follow the AP655F control architecture, so no adapter or rewiring is needed.
• Field replacement: plug-in layout means the repair can be done during a normal maintenance window.
• Genuine APOLLO part: built to original specification for repeatable behaviour in dust, vibration and heat.

Technical Overview

Symptoms That Point to a Failing Sensor

A degraded sensor seldom throws a clean electrical fault. It shows up as behaviour: mat thickness creeping over a long pass with no change at the reference, a screed that keeps correcting in the same direction, or grade alarms that disappear after a restart and return an hour later. Before stripping hydraulics, a service team should check the sensor first, because a biased signal forces every downstream correction.

• Grade deviation that grows steadily along the run.
• Repeated grade alarms with normal hydraulic pressures.
• Corrosion or damage at the sensor connector or arm.
• Known impact during transport or site movement.

Stock, Packing and Ordering

Each sensor is packed in an APOLLO branded carton with shock-proof foam for export. Minimum order quantity is one set, so a workshop can test a single unit before committing to a fleet order. Payment terms include L/C, T/T and Western Union, with delivery normally seven to fifteen days after payment.

When inquiring, please confirm the machine model AP655F together with part number 491-4597. Photos of the original sensor are welcome and our technical team will compare them with current stock before shipment, so the correct unit reaches your workshop. For price lists and combined orders of leveling system spare parts, contact our sales team.