What causes fault code PKG-CHECK1 (Checkweigher — Weight Reject / Out of Tolerance)?

Product genuinely underweight or overweight — fill station issue, missing component, or double-feed. Checkweigher calibration drifted — load cell zero offset or span error. Conveyor vibration affecting checkweigher accuracy — external vibration source nearby. Product not stable on the weigh belt — bouncing or sliding during weighment. Checkweigher speed too fast for the product weight and settling time

How do I fix fault code PKG-CHECK1?

Verify rejected product weight with a bench scale — confirm if the reject was valid. Run a checkweigher calibration check with a known test weight — note zero and span accuracy. If calibration is off, perform full calibration procedure using certified test weights. Check for vibration sources — compressors, conveyors, or foot traffic near the checkweigher. Verify product is stable on the weigh belt — check belt speed and product spacing. If vibration is unavoidable, adjust the digital filter settings — increase filter strength (reduces speed but improves accuracy)

Checkweigher — Weight Reject / Out of Tolerance

PKG-CHECK1

In-line checkweigher detected a product outside the acceptable weight range. Product has been rejected. May indicate fill level issue, missing components, or checkweigher calibration drift.

medium packaging

packaging checkweigher weight reject calibration load cell

Probable Causes (ranked)

Product genuinely underweight or overweight — fill station issue, missing component, or double-feed
Checkweigher calibration drifted — load cell zero offset or span error
Conveyor vibration affecting checkweigher accuracy — external vibration source nearby
Product not stable on the weigh belt — bouncing or sliding during weighment
Checkweigher speed too fast for the product weight and settling time

Fix Steps

1 Verify rejected product weight with a bench scale — confirm if the reject was valid
2 Run a checkweigher calibration check with a known test weight — note zero and span accuracy
3 If calibration is off, perform full calibration procedure using certified test weights
4 Check for vibration sources — compressors, conveyors, or foot traffic near the checkweigher
5 Verify product is stable on the weigh belt — check belt speed and product spacing
6 If vibration is unavoidable, adjust the digital filter settings — increase filter strength (reduces speed but improves accuracy)

Field Trick

Checkweighers hate vibration. If yours suddenly starts rejecting good products, check if someone put a new machine, compressor, or forklift traffic route near the checkweigher. Isolating a checkweigher from the floor with vibration damping pads improves accuracy by 50% in a typical plant environment.

Suggested Replacement Parts

Parts matched to fault category: Load Cell

Rice Lake RL75016 S-Beam Load Cell P/N: RL75016-500 500 lb capacity, S-beam, 3mV/V, NTEP certified

Amazon $185.00 McMaster-Carr $220.00 Grainger $245.00

Prices are estimates. Verify part numbers match your equipment before ordering.

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