For many owners, RECD compliance for diesel generators appears complete once the device has been installed and the invoice has been filed. In reality, installation is only the beginning of an ongoing responsibility involving correct operation, maintenance, documentation, and verification of current regulatory conditions.
An RECD, or Retrofit Emission Control Device, is fitted to an existing diesel generator’s exhaust system to reduce specified pollutants. Its performance depends on the engine, treatment technology, exhaust temperature, operating load, installation quality, and servicing. Owners must therefore understand both what the device can achieve and what it cannot guarantee.
Ownership Responsibility Does Not End With the Supplier
The manufacturer is responsible for supplying the contracted product and meeting its agreed technical, installation, and warranty obligations. The generator owner, however, remains responsible for how the equipment is operated and maintained at the site. A supplier may recommend inspection intervals, pressure limits, regeneration procedures, and cleaning methods, but facility personnel must follow those instructions. If alarms are ignored, filters are not serviced, or unauthorised changes are made to the exhaust system, the RECD may no longer function as intended.
Owners should also remember that product documentation and permission to operate a generator are separate matters. A suitable device does not automatically override operating restrictions, emergency-use conditions, consent requirements, or location-specific air-quality directions.
An RECD Must Match the Actual Engine
A diesel generator’s kVA rating provides only a general indication of size. It does not reveal every parameter needed to select exhaust after-treatment equipment. Generators with the same capacity can contain different engines and produce different exhaust-flow rates, temperatures, and backpressure conditions. Their working environments may also vary significantly. A DG set that runs occasionally at low load does not necessarily create the same conditions as one operating for longer periods under stable demand.
The manufacturer should assess the engine make, model, rated output, manufacturing year, exhaust dimensions, existing silencer, stack arrangement, operating hours, and typical load. The selected RECD should be supported by documents relevant to its model and intended engine or power application. Owners should keep a copy of the engine nameplate photograph and compare it with the information used in the supplier’s proposal. An incorrect engine model entered during procurement can affect the entire technical assessment.
Engine Health Comes Before Exhaust Treatment
An RECD is designed to treat exhaust; it is not intended to repair poor combustion. A generator producing excessive smoke may have injector problems, restricted air intake, fuel-system faults, oil consumption, overloading, or another mechanical issue. Installing a treatment device without addressing these conditions can lead to unusually rapid soot accumulation. Filters may require frequent cleaning, pressure can rise more quickly, and maintenance costs may exceed the original estimate.
A baseline engine inspection before installation is therefore valuable. The owner should confirm that routine servicing has been completed and investigate abnormal smoke, noise, oil use, or unstable operation. This creates more predictable operating conditions for the RECD and helps distinguish engine problems from treatment-system problems later.
The Device Must Be Operated Within Its Conditions
Many RECD technologies depend on exhaust temperature and load. Catalytic activity and filter regeneration may behave differently when the generator operates only for brief periods or remains consistently underloaded. The supplier should explain how collected soot is managed. Some designs may regenerate under suitable operating temperatures, while others may require an active process or external cleaning. Owners should understand which method applies to their product and what happens if the required conditions are not achieved.
A monthly no-load test may confirm that a generator starts, but it may not create the same exhaust conditions as real operation. Test practices should follow engine, generator, safety, and RECD instructions rather than being improvised solely to raise temperature.
Backpressure Needs Continuing Attention
Placing an RECD in the exhaust line adds resistance. Correct engineering keeps that resistance within acceptable limits, but soot loading, damaged components, incorrect cleaning, or unauthorised piping changes can increase backpressure over time. The owner should know how pressure is monitored and what reading indicates that attention is required. Depending on the system, this may involve a gauge, sensor, differential-pressure instrument, display, or alarm.
An abnormal reading should not be cleared or ignored without identifying the cause. Continuing to operate the generator against excessive exhaust restriction may affect engine performance and equipment reliability. Pressure records are also useful for preventive maintenance. A gradual increase can help technicians identify soot accumulation before the condition becomes urgent.
Documentation Must Remain Connected to the Equipment
A common ownership problem arises when the invoice is stored by accounts, the certificate remains with procurement, the maintenance manual is left in the DG room, and the commissioning report cannot be found. Compliance becomes difficult to demonstrate when the records are disconnected. The owner should maintain one digital and physical file linking the generator to the installed RECD. It should contain engine details, product model and serial number, relevant test or certification documents, approved installation drawing, invoice, commissioning record, operating manual, warranty, service history, and training information.
Documents should be model-specific wherever applicable. A certificate bearing the manufacturer’s name does not automatically cover every device the company sells. Annexures may contain important limits relating to power range, configuration, test conditions, or intended application. If the RECD or its major internal components are replaced, the owner should update the file instead of continuing to rely on the original records.
Selecting a Responsible Manufacturer
When evaluating an RECD manufacturer in India, owners should look beyond broad claims such as “CPCB approved,” “maintenance-free,” or “suitable for every DG.” The manufacturer should explain the exact basis of its claims and provide evidence relevant to the product being offered. A competent company should also discuss technical limitations. It should identify the exhaust conditions the system requires, explain the cleaning method, define acceptable backpressure, and disclose which parts may need replacement.
After-sales capability is equally important. Owners should know where service technicians are located, how a complaint is registered, what response time applies, and whether cleaning or regeneration is carried out on-site or elsewhere. The warranty should clarify coverage for the housing, filtration or catalyst elements, sensors, controller, supplied wiring, fabrication, and installation workmanship. Verbal assurances should be transferred into the purchase agreement.
Site Modifications Can Affect the Original Installation
DG rooms and utility areas often change over time. New pipes may be added, ventilation systems altered, cables rerouted, or nearby equipment installed. These modifications can restrict access to the RECD or expose components to unsuitable conditions. The exhaust system itself should not be changed without technical review. Adding bends, replacing the silencer, modifying the stack, relocating sensors, or installing a bypass can affect pressure and treatment performance.
Owners should require facility contractors to obtain approval before working on the RECD or associated exhaust line. The final drawing should be updated whenever an authorised change is completed.
“CPCB Compliant” Requires Careful Interpretation
The expression “CPCB compliant” should not be treated as a permanent blanket status. Owners need to understand which product record, test procedure, standard, or regulatory direction supports the statement. Current national information should be checked through the Central Pollution Control Board. Depending on the location, the relevant state pollution control board or pollution control committee may publish additional requirements.
Owners in the National Capital Region should also monitor the Commission for Air Quality Management. CAQM has issued directions concerning regulated operation of DG sets across sectors in NCR. Its October 2024 publication referred to implementation of the schedule under Direction No. 76, but later amendments, GRAP measures, or new instructions should always be checked. A regulation applicable to one region, generator category, or period should not be assumed to apply identically throughout India.
Maintenance Is Part of Compliance Management
RECD servicing should be integrated into the generator’s preventive-maintenance programme. The schedule should account for running hours, load profile, engine condition, soot accumulation, fuel quality, and the manufacturer’s instructions. Maintenance records should describe the work performed rather than simply stating “RECD serviced.” Useful information can include pressure readings, sensor checks, filter condition, cleaning method, replaced components, alarm history, and technician observations.
Facility staff should receive refresher training when operators change. A technically sound installation can become ineffective if no one on-site understands the display, alarms, or cleaning indicators.
Frequently Asked Questions
Does an RECD require maintenance after installation?
Yes. Inspection, pressure monitoring, filter cleaning, regeneration, sensor checks, or component replacement may be required, depending on the technology and operating conditions.
Can one RECD model fit every generator of the same kVA?
Not necessarily. Engines with the same generator rating can have different exhaust-flow, temperature, and backpressure characteristics.
Does an RECD permit DG use during all air-quality restrictions?
No. Separate operating restrictions or emergency-use conditions may still apply. Owners should verify current official directions.
Who is responsible for maintaining RECD records?
The generator owner or facility operator should retain model-specific documents, commissioning information, maintenance reports, warranty records, and regulatory correspondence.
What should an owner do after an RECD alarm?
Follow the manufacturer’s operating instructions, reduce or stop operation if required, record the alarm, and contact qualified technical support rather than simply resetting it.

Conclusion
An RECD should be managed as operating pollution-control equipment, not as a one-time compliance purchase. Owners must preserve product traceability, maintain a healthy engine, monitor exhaust restriction, follow servicing instructions, and review regulatory updates. Aceget can help businesses assess retrofit emission-control requirements for existing diesel generators. Before purchasing or operating an RECD-equipped DG set, owners should obtain a site-specific technical proposal and confirm current requirements through official sources. Long-term compliance depends on informed ownership as much as it depends on the device itself.