Allen-Bradley 700-N400A1

Common Fault Conditions

Timing Drift

The relay timing period has shifted outside the set value, causing premature or delayed contact switching.
Inspect the pneumatic bellows for cracks or air leaks. Clean the orifice and recalibrate the timing dial. Replace the timer head if the bellows is damaged.

No Timing Action

The timed contacts switch immediately without any delay when the relay coil is energized.
Check that the pneumatic orifice is not blocked or fully open. Verify the timing adjustment dial is set correctly. Inspect the bellows for collapse or failure and replace if necessary.

Contact Failure to Transfer

The timed contacts do not transfer state after the timing period has elapsed.
Inspect the contact mechanism for wear or contamination. Verify the relay base contacts are functioning correctly. Replace the timer attachment or relay base as appropriate.

Mechanical Binding

The timing mechanism is physically stuck, preventing normal operation of the timed contacts.
Remove the timer head from the relay base and inspect for foreign material or corrosion. Do not lubricate the pneumatic orifice. Replace the unit if binding persists.

Inconsistent Timing

The timing period varies significantly between successive operations, causing unreliable sequencing.
Check for temperature extremes outside the rated operating range. Inspect the bellows and orifice for partial blockage or micro-cracks. Replace the timer head if repeatability cannot be restored.

Physical Attachment Failure

The timer head does not seat securely on the relay base, causing intermittent or no timing function.
Verify compatibility of the timer head with the specific relay base model. Inspect the mounting clips and base interface for damage. Re-seat or replace the timer attachment.