When evaluating an RECD manufacturer in India, it is easy to focus on the visible parts of a product—its price, size, appearance or advertised features. However, the more important differences often lie behind the product: technical applicability, certification documentation, engineering support, installation capability and after-sales service.

CPCB's published RECD procedure addresses retrofit emission-control devices for in-use diesel-operated internal-combustion engines used in genset applications up to 800 kW gross mechanical power. The procedure covers applicability, requirements, certification and testing. For a generator owner, therefore, the “best” manufacturer should not simply mean the company offering the lowest quotation. It should mean a manufacturer whose product and support can be properly evaluated for the intended DG-set application.

1. Technical Applicability Comes First

The first characteristic that separates a capable manufacturer from a generic seller is the ability to identify whether its product is appropriate for a particular generator.

Before recommending an RECD, the manufacturer should have access to information such as:

• Engine manufacturer

• Engine model

• Engine serial number

• Gross mechanical power

• DG-set capacity

• Existing exhaust configuration

• Installation conditions

CPCB's published manufacturer list specifies RECD applicability across different ranges of in-use diesel genset engine power in kW, rather than treating all generators as one category.

This makes technical matching an important part of the buying process.

Why kVA Alone Isn't Enough

A customer might say:

“I have a 750 kVA DG set. Which RECD should I buy?”

That is a useful starting point, but it is not the complete technical enquiry.

The engine model and gross mechanical power should also be established so the proposed RECD can be evaluated against its documented applicability.

2. Product Documentation Should Be Clear

A strong manufacturer should be able to provide clear information about the product being offered.

Depending on the product, buyers should ask for:

• Product model

• Technical datasheet

• Applicable engine-power range

• Phase applicability

• Certification/test information

• Installation instructions

• Maintenance information

• Warranty terms

CPCB's published manufacturer list identifies certified manufacturers, applicable engine-power ranges, Phase I/Phase II applicability and certification agencies.

This gives buyers a useful framework for checking supplier claims.

Match the Documents

A simple but valuable check is:

Quoted product model = Technical datasheet = Certification information

If the model numbers or application details differ, ask the supplier for clarification before proceeding.

3. Certification Transparency Matters

A good manufacturer should not expect customers to accept compliance-related statements without supporting information.

Instead of relying on phrases such as:

“CPCB approved product”

ask for the relevant documentation.

Important questions include:

• What exact product has been certified?

• What engine-power range applies?

• Which phase is covered?

• Which certification agency is identified?

• Does the documentation correspond to the quoted product?

CPCB's published list identifies certification agencies for listed manufacturers, including ICAT and ARAI for different entries.

The goal is not simply to find the words “CPCB” on a brochure. The goal is to establish the relationship between the specific product and its documented application.

4. Engineering Capability Is More Important Than Marketing

RECD installation involves an existing diesel-generator exhaust system.

A technically capable manufacturer should therefore be able to discuss issues such as:

• Exhaust diameter

• Flange arrangement

• Silencer configuration

• Pipe routing

• Mounting location

• Available space

• Maintenance access

• Exhaust back pressure considerations

CPCB's RECD procedure includes exhaust back pressure among the technical parameters addressed within its compliance-testing framework.

This is one reason an application-focused manufacturer can add more value than a company that simply ships a standard product.

Site Inspection Can Be Valuable

Depending on the installation, the manufacturer may recommend a site assessment.

A site visit can help determine:

• Where the RECD can be installed

• Whether fabrication is required

• How the exhaust will be connected

• Whether sufficient access exists

• Whether maintenance can be performed safely

The exact requirements should be established for the specific DG set.

5. A Good Manufacturer Understands Different DG Applications

Diesel generators are used in many environments.

Examples include:

• Commercial buildings

• Manufacturing facilities

• Hospitals

• Data centres

• Hotels

• Construction projects

• Educational institutions

• Infrastructure facilities

Each site can have different installation constraints.

For example, a generator located in a compact DG room may have significantly less installation space than one installed in an open industrial area.

A manufacturer that evaluates the actual site can identify such practical issues before equipment delivery.

6. Product Quality Should Be Evaluated Systematically

Product quality should not be judged only by external appearance.

Consider:

Construction

Review the manufacturer's technical specifications and construction information.

Components

Understand which major components are included.

Monitoring

Where applicable, determine what sensors or monitoring components are provided.

Serviceability

Ask how maintenance and component replacement are handled.

Documentation

Check whether operating and maintenance information is supplied.

A professional evaluation considers the entire system rather than just the housing or external finish.

Ask What Is Included

Before accepting a quotation, establish whether the price includes:

• Equipment

• Accessories

• Installation

• Exhaust fabrication

• Transportation

• Commissioning

• Documentation

• Warranty

• Service

This prevents unexpected project costs.

8. Installation Support Separates Manufacturers From Resellers

Some companies sell equipment but outsource installation.

That is not necessarily a problem, provided responsibilities are clearly defined.

Ask:

Who will install the system?

Who will perform commissioning?

Who is responsible if an installation issue occurs?

Who handles warranty claims?

Who supplies replacement components?

If a dealer or reseller is involved, determine whether the original manufacturer remains responsible for technical support.

Why Responsibility Should Be Clear

Consider a situation where:

• The manufacturer supplied the equipment.

• The contractor performed fabrication.

• Dealer arranged installation.

• Another company handles maintenance.

If a problem occurs, unclear responsibility can delay resolution.

A strong commercial proposal should define responsibilities in writing.

9. Warranty Should Be Specific

Warranty duration alone does not tell the complete story.

Ask for written information covering:

• Warranty period

• Covered components

• Labour

• Site visits

• Replacement parts

• Exclusions

• Claim procedure

For example, “two-year warranty” is less useful than:

“Two-year warranty covering the specified components under the stated operating conditions, subject to the manufacturer's warranty terms.”

The exact terms should always come from the manufacturer.

10. After-Sales Service Is a Major Differentiator

The relationship with an RECD manufacturer continues after installation.

A reliable support structure may include:

• Technical troubleshooting

• Preventive-maintenance guidance

• Spare-parts availability

• Service engineers

• Remote assistance

• Warranty support

• Site visits

For a facility operating several DG sets, service availability can be particularly important.

Ask About Spare Parts

Before ordering, determine:

• Which parts are replaceable?

• Are parts readily available?

• Who supplies them?

• How are they ordered?

• What is the normal service process?

This helps the buyer understand the long-term ownership requirements.

11. Manufacturer Experience Matters

Experience should not replace certification or documentation, but it can be valuable.

Ask whether the manufacturer has handled applications involving:

• Similar engine models

• Similar engine-power ranges

• Similar exhaust systems

• Multiple DG sets

• Industrial installations

• Commercial facilities

A manufacturer familiar with comparable projects may be better prepared to anticipate installation challenges.

12. Look for Application-Specific Recommendations

A manufacturer should not automatically recommend the same product to every customer.

A stronger approach is:

Customer DG details → Technical assessment → Applicable product → Installation assessment → Commercial proposal

This indicates that the manufacturer is considering the actual application.

A weaker approach is:

Customer asks for RECD → Seller immediately sends one generic price

The second approach may be faster, but it provides less technical confidence.

13. Understand Phase Applicability

CPCB's published manufacturer list distinguishes between Phase I and Phase II applicability for listed RECD manufacturers.

Therefore, buyers should not simply ask:

“Is your RECD CPCB approved?”

A more useful question is:

“Which phase and engine-power range does the proposed RECD cover, and what documentation supports that application?”

This encourages product-specific verification.

14. Beware of Universal Claims

A manufacturer should be able to explain the technical basis for its recommendation.

Be cautious with unsupported statements such as:

• “One product fits every DG.”

• “No engine details are required.”

• “All generators use the same RECD.”

• “CPCB approval applies automatically to every model.”

• “Installation does not need technical evaluation.”

These claims should be investigated rather than accepted at face value.

CPCB's published manufacturer list itself shows variation in documented engine-power ranges and phases.

15. Check the Manufacturer's Current Status

Official information should always be checked against the latest available CPCB material.

CPCB maintains a generator-set section containing Type Approval/COP information and other relevant resources.

The RECD manufacturer list available from CPCB is specifically dated 09-05-2025, so it should be treated as a dated official reference rather than assumed to be a permanently current list.

Before purchasing, check whether CPCB has published a newer relevant update.

16. Don't Ignore State-Level Requirements

CPCB information is important, but the requirements applicable to a particular installation may also involve the relevant State Pollution Control Board or Pollution Control Committee.

This is especially important when a project involves:

• Regulatory submissions

• Consent conditions

• Specific site directions

• Large installations

• Multiple DG sets

Where there is uncertainty, obtain clarification from the appropriate authority or a qualified environmental professional.

Questions to Ask the Manufacturer

Before finalizing an order, ask:

Technical

What engine-power range does the proposed RECD cover?

Product

What is the exact model number?

Certification

What certification/test documentation is available?

Installation

Will the existing exhaust arrangement be evaluated?

Commissioning

Who will commission the system?

Warranty

What exactly is covered?

Service

Who handles technical complaints after installation?

Spare Parts

How are replacement components supplied?

Clear answers to these questions are a positive sign during supplier evaluation.

Checklist for Selecting a Strong Manufacturer

Before placing an order, confirm:

• Actual manufacturer identified

• Engine model recorded

• Gross mechanical power verified

• DG capacity recorded

• Exact RECD model identified

• Applicable engine range checked

• Phase applicability checked

• Certification information reviewed

• Technical datasheet received

• Exhaust arrangement evaluated

• Installation scope documented

• Commissioning responsibility defined

• Warranty terms received

• Spare-parts process understood

• Service support confirmed

• Total cost compared

A Better Way to Evaluate an RECD Supplier for DG Sets

For organizations searching for an RECD supplier for DG sets, the evaluation should follow a consistent process.

First, identify the exact generator and engine.

Second, determine the applicable product range.

Third, review the manufacturer's technical and certification documentation.

Fourth, assess the physical installation requirements.

Fifth, compare complete commercial proposals.

Finally, evaluate warranty and long-term service.

This process helps prevent price from becoming the only selection criterion.

What Really Sets the Best Manufacturers Apart?

The strongest manufacturers tend to demonstrate several qualities simultaneously:

Technical clarity — They can explain product applicability.

Documentation — They provide information that can be reviewed.

Engineering support — They understand installation requirements.

Transparency — They clearly define what is included.

Service capability — They remain available after installation.

Regulatory awareness — They encourage verification against current official requirements instead of relying on unsupported claims.

No single factor should be considered proof of overall quality. The complete picture matters.

Final Thoughts

The best RECD manufacturer is not necessarily the one with the biggest advertisement or the lowest price. It is the one that can provide a technically appropriate product, clear documentation, defined installation support and dependable after-sales assistance. For anyone comparing an RECD supplier for DG sets, the right approach is therefore to verify the generator's technical details first, identify the appropriate product, examine supporting documentation and then compare installation, warranty, service and total project cost. Finally, buyers should verify the latest CPCB information and any requirements applicable to their specific installation before purchasing or installing an RECD. Official lists and regulatory information can be updated, and local requirements may also need to be considered.