Why Does Differential Pressure Rise Quickly After Installing New Filters?

Use remote displays, historian records, maintenance records, external observations, and other already-authorized sources first. Do not open or enter an energized collector, disconnect live lines, bypass interlocks, force pulses, defeat guards, or change fan, damper, controller, or cleaning settings for this workflow. OSHA’s hazardous-energy standard covers servicing and maintenance in which unexpected energization, startup, or stored-energy release could injure employees and requires an employer energy-control program within its scope. [1] The employer’s procedure, collector manual, hazard assessment, permits, and authorized personnel govern any inspection. If the needed evidence cannot be obtained safely, record the owner and route the item to HOLD — resolve evidence.

Confirm the instrument manufacturer, model, range, configuration, high- and low-side tap locations, tubing route, connection state, displayed engineering unit, signal destination, zero and span history, and calibration status. Treat blocked, leaking, reversed, pinched, or moisture-affected impulse lines as evidence categories, not findings. The Dwyer Series 607 instructions are model-specific: they distinguish high and low pressure ports, warn that orientation can admit condensed moisture, and call for periodic calibration checks. [2] Apply those statements only to the named instrument. For any other device, use its current manual and qualified instrumentation personnel. If range, taps, line condition, time stamp, or calibration is uncertain, do not interpret the trend; HOLD.

Compare like with like: the same sensing points, instrument configuration, fan and damper state, duct lineup, process rate, collector compartments, cleaning state, hopper state, temperature and moisture context, and time basis. Capture the pre-change record, post-startup record, cleaning events, process events, and any control or maintenance changes on one timeline. EPA lists pressure differential alongside inlet temperature, temperature differential, exhaust gas flow rate, cleaning mechanism operation, fan current, and outlet indicators; this supports a multi-indicator record rather than a differential-pressure-only diagnosis. [3] Use collector/site baseline. If the old and new observations were made under different operating states or unsynchronized clocks, label them non-comparable and HOLD.

Reconcile the work order, changeout checklist, filter count, position map, part or drawing, dimensions, media, end construction, gasket or seal orientation, seating, attachment hardware, cartridge support or bag-and-cage relationship, access-cover condition, and any installation exceptions. Review only records and safely available observations under the controlling procedure. Donaldson’s installation-oriented troubleshooting questions distinguish filter orientation, snap-band seating, cuffs, gaskets, and attachment hardware as separate evidence fields. [8] Those fields do not prove why differential pressure rose. Record filter seating, seals, orientation, support, and quantity; preserve photographs and a traceable spare or removed sample when the site permits. Unknown fit or mixed configuration routes to HOLD.

Record fan status, speed command or drive state, damper positions, duct and hood lineup, open or closed branches, process equipment online, capture observations, exhaust restrictions, recirculation configuration, and any control changes. Do not infer airflow from differential pressure alone and do not change system balance to lower a reading. Donaldson notes that collector differential pressure represents resistance to airflow and that an operating value depends on air volume and dust characteristics in its DFPRE manual context. [5] Compare fan, damper, duct, capture, and operating state against the collector/site baseline and design record. A missing airflow measurement or undocumented control change is an evidence gap, not proof of a filter problem.

Use controller history, alarm and event records, maintenance logs, compressed-air quality records, manifold observations, and authorized functional-test results. Distinguish a controller demand from actual solenoid, diaphragm-valve, and blowpipe response. Donaldson’s on-demand cleaning article identifies the controller, timer board, solenoids, diaphragm valves, and compressed-air path as distinct components; its electrical troubleshooting steps require qualified personnel and are not reproduced here. [6] The DFPRE manual separately lists pressure connections, compressed-air supply, valves, controller, and dust-container seal in its model-specific checks. [5] Record controller, compressed-air quality, manifold, valves, and blowpipes. Use collector/site baseline; never invent pulse settings.

Build an event log for production rate, material or formulation changes, start-stop pattern, upset events, dust concentration evidence, particle size or behavior, sticky or hygroscopic material, temperature, humidity, and any upstream equipment changes. EPA explains that dust accumulation increases pressure drop and that filter performance is affected by exposure conditions and cleaning frequency. [3] This establishes evidence categories, not a diagnosis for this collector. Compare dust rate, particle behavior, process changes, and event timing with the synchronized trend. A coincident event supports a question to verify; it does not prove causation. Preserve lot, batch, recipe, shift, maintenance, and weather records when relevant and site-approved.

Record process temperature, shutdown and startup sequence, ambient conditions, insulation or heat-trace status where applicable, compressed-air moisture records, drains or separators, visible wetness reported under authorized inspection, and whether the sensing lines share the same moisture event. EPA notes that condensation can affect fabric-filter casing and can contribute to bag blinding in relevant gas-stream conditions. [3] Dwyer’s named transmitter manual separately shows that condensation in tubing can affect the instrument installation. [2] Keep those two paths distinct: a wet sensing line is not proof of wet filters, and suspected wet media is not proof of an invalid transmitter. Obtain dew-point or condensation evidence before choosing either hypothesis.

Review hopper-level history, dust-container state, rotary valve or screw-conveyor status, bridging observations, discharge interlocks, seal condition, disposal timing, and whether dust can contact the filter elements again. Donaldson states that a hopper is not intended as storage and links regular discharge to keeping accumulated dust away from filter elements. [7] Its DFPRE manual also includes dust-container level and seal checks in the named equipment’s maintenance and pressure-drop context. [5] Record hopper level, discharge equipment, bridging, and re-entrainment as separate questions. Do not clear a blockage or access a hopper under this article; unsafe or unavailable evidence remains on HOLD.

Compare the purchase order, approved drawing, supplier part reference, collector model and compartment, installed quantity, dimensions, filter area documented by the manufacturer, media and surface treatment, pleat or bag construction, end caps or top and bottom style, gaskets, cages or supports, and any revision or substitution. Confirm whether the prior set was the same documented configuration before calling it a baseline. A different media, geometry, quantity, or support arrangement may change resistance, but the record must establish what changed and whether it is approved for the named collector. Record part, dimensions, media, treatment, and collector configuration. A photograph or nominal dimension alone does not prove identity, compatibility, performance, or root cause. Mixed or untraceable evidence routes to HOLD and a defined purchasing inquiry.

Assemble one evidence table with the observation, source, time stamp, operating state, comparison basis, document revision, evidence owner, unresolved conflict, and next authorized decision. The outcome is either a comparable evidence package for the buyer-appointed authority or HOLD — resolve evidence. Do not label a filter blinded, wrong, failed, compatible, corrected, or ready for service from differential pressure alone. Do not recommend a control change, filter change, or restart from this workflow. The buyer-appointed authority decides whether qualified instrumentation, collector OEM, system engineer, EHS, maintenance, process, or filter-supply input is needed. Preserve the unchanged trend and configuration record so later verification is possible.