CF ChatterFix
Preventive Maintenance

Cleanroom Air Handler Filter Differential

The cleanroom air handler filter differential is how a loading HEPA shows up before the room misses its own limit. The technician writes the as-found reading and compares it with the last one on the asset. Do not change a room differential setpoint from this work order. Anything past that line belongs to the site's own procedure, the OEM manual, or a permit. This is the inspection ChatterFix schedules. It is not itself permission to go further.

Interval Monthly
Est. Duration 1.5 hrs
Steps 5
Applies To Pharmaceutical & Life Sciences

The Procedure

The steps ChatterFix schedules for this PM. Every step is a checkable item on the work order — a technician can speak their way through it without touching a keyboard.

  1. Record supply-fan differential and compare it to the last reading
  2. Inspect the cooling coil face and the damper travel
  3. Confirm the HEPA housing clamps and gel seal are intact
  4. Do not change a room differential setpoint from this work order
  5. Write a deviation if the as-found reading is outside the site limit

Why This PM Exists

The cleanroom air handler filter differential is how a loading HEPA shows up before the room misses its own limit. The technician writes the as-found reading and compares it with the last one on the asset. Do not change a room differential setpoint from this work order. Anything past that line belongs to the site's own procedure, the OEM manual, or a permit. This is the inspection ChatterFix schedules. It is not itself permission to go further.

What Skipping It Looks Like

The room feels the same, so somebody nudges the setpoint and the filter loading disappears from the record. The round still closes, the number never lands on the asset, and the next person inherits a guess. Do not change a room differential setpoint from this work order.

Setting the interval

Monthly, alongside the last differential on the asset. An as-found reading outside the limit the site already published is a finding. It does not become a new setpoint on this work order.

Equipment This Covers

Common Questions

How often should this PM run?
Monthly. Monthly, alongside the last differential on the asset. An as-found reading outside the limit the site already published is a finding. It does not become a new setpoint on this work order.
How long does it take?
Budget about 1.5 hours for a technician working to the standard procedure. ChatterFix uses that estimate for capacity planning, then learns your plant's actual time from completed work orders.
What happens if we skip it?
The room feels the same, so somebody nudges the setpoint and the filter loading disappears from the record. The round still closes, the number never lands on the asset, and the next person inherits a guess. Do not change a room differential setpoint from this work order.
Can I use this checklist in ChatterFix?
Yes — this exact procedure ships in the Pharmaceutical & Life Sciences industry pack. Pick your industry at signup and it is scheduled on the right assets automatically, with no configuration.

Related Procedures

Stop Retyping Your PM Library

This procedure — and every other PM for your industry — is already built into ChatterFix. Pick your industry and it lands on the right equipment, on the right interval, in about three minutes.