Choosing an RECD vendor is not simply about comparing three quotations and selecting the lowest price. A Retrofit Emission Control Device has to match the specific diesel generator, exhaust conditions, operating pattern and applicable compliance requirements. More importantly, the vendor should be able to provide reliable certification and technical documentation for the proposed system.

View the CPCB list of certified RECD manufacturersThe Central Pollution Control Board (CPCB) publishes information on manufacturers certified for Retrofit Emission Control Devices applicable to in-use diesel genset engines up to 800 kW, including the applicable engine-power range and certification agency. This makes vendor verification an important part of the procurement process..

Aceget guide on how to choose CPCB-approved RECD vendorsFor a practical overview of the vendor-selection process, the explains the major checks buyers should complete before finalising a supplier.

1. Start With the Exact DG Set Details

An RECD should not be selected only from the generator's kVA rating. Before approaching vendors, collect the engine make, engine model, rated power, emission phase, exhaust flow, exhaust temperature and typical operating load.

Also keep the DG nameplate and engine nameplate photographs ready. These details allow the vendor to determine whether a particular RECD model is suitable for the engine.

A quotation based only on a statement such as "RECD required for a 500 kVA DG" may not provide enough technical information for a proper comparison.

2. Verify the Certification and Applicability Range

One of the first checks should be whether the proposed RECD model actually appears within the relevant CPCB certification framework.

Do not stop at a certificate bearing the name of a testing agency. Check:

RECD model and variant
Applicable engine power range
Engine family or application covered
Certification or test reference
Certification agency
Type Approval details
Conformity of Production requirements, where applicable

Read the CPCB RECD testing procedureCPCB's published procedure explains that RECDs are developed, optimised and certified for applicable DG engine families, with Type Approval and Conformity of Production forming part of the certification framework..

This distinction is important because a vendor may offer a certified product, but the certificate still needs to be relevant to the DG set on which the device will be installed.

3. Check Who Conducted the Testing

The certification agency is another useful verification point. CPCB's published manufacturer list identifies the certification agency associated with different RECD models.

When evaluating a quotation, ask the vendor to provide the complete certificate or test documentation rather than only a brochure or screenshot.

You should be able to match the proposed device with the documentation supplied by the vendor. If the vendor avoids sharing model-specific information, that should be treated as a warning sign.

4. Ask How the RECD Was Sized

Good RECD selection involves engineering calculations rather than simply matching the device to a kVA number.

Ask the vendor:

What exhaust flow was used for sizing?
What exhaust temperature was considered?
What is the expected pressure drop?
What is the expected total backpressure after installation?
What is the engine manufacturer's permissible backpressure?
How does the design account for the actual exhaust piping?
What operating load was considered?

Aceget guide on using OEM exhaust-flow data when specifying an RECDThe provides a useful reference for understanding why these details matter.

A technically responsible vendor should be able to explain the selection calculation clearly.

5. Look Beyond the Device Price

Two RECD quotations may appear very different because their scopes are different.

One quotation may include only the device, while another may include:

Site survey
Exhaust modification
Supports and structural work
Insulation
Sensors and controller
Installation
Testing and commissioning
Documentation
Warranty
Service visits

Therefore, compare quotations on a like-for-like basis.

A lower equipment price does not necessarily mean a lower project cost if important installation or commissioning activities have been excluded.

6. Evaluate Installation Capability

RECD installation can involve modifications to the existing exhaust arrangement. The vendor should understand the site conditions before finalising the design.

During the site survey, check whether the vendor reviews:

Available installation space
Existing exhaust routing
Pipe diameter and bends
Support arrangements
Access for maintenance
Generator-room ventilation
Hot-surface protection
Sensor locations
Backpressure measurement points

For larger projects, it is useful to ask for a general arrangement drawing before installation. This gives the buyer an opportunity to review the proposed arrangement instead of discovering problems after fabrication.

7. Ask About Testing and Commissioning

The vendor's responsibility should not end when the RECD reaches the site.

Ask what commissioning activities are included. These may include checking exhaust connections, sensors, pressure readings, controller operation and other relevant parameters.

The vendor should also clearly state which testing is included in the commercial offer and which testing has to be arranged separately by the customer.

A proper handover should include relevant technical documents, installation information and test records.

8. Investigate After-Sales Service

An RECD is an operating system, not simply a fabricated exhaust component. Its long-term performance depends on appropriate inspection, maintenance and troubleshooting.

Before selecting a supplier, ask:

Where is the nearest service team?
What is the expected response time?
Who will attend warranty complaints?
What consumables or maintenance are required?
How frequently should inspections be performed?
What happens if the controller or sensor develops a fault?
Is AMC available after the warranty period?

For sites such as hospitals, commercial buildings, telecom facilities and industrial plants, service availability can be as important as the initial purchase price.

9. Ask for Relevant Installation References

A vendor's previous experience can provide valuable information that a brochure cannot.

Request references for DG sets similar to yours in terms of:

Generator capacity
Engine type
Operating hours
Site environment
Installation complexity

If possible, speak with an existing customer and ask about installation quality, response time, maintenance requirements and overall experience.

Aceget guide on questions to ask during an RECD factory visitYou can also use a factory visit as part of the evaluation process. The explains how buyers can examine certification records, production practices, testing documentation and service capability.

10. Use a Simple Vendor Comparison Sheet

Before making the final decision, compare every shortlisted supplier against the same criteria.

Evaluation Area	Vendor A	Vendor B	Vendor C
Applicable RECD model
Certification documentation
Applicable engine range
Certification agency
Exhaust-flow basis
Backpressure calculation
Installation scope
Commissioning scope
Warranty
Service support
Customer references
Total project cost

This approach prevents the procurement decision from being driven by price alone.

Common Red Flags When Selecting an RECD Vendor

Be careful if a vendor:

Provides only a generic certificate without explaining applicability.
Selects the device only from the DG's kVA rating.
Refuses to provide technical calculations.
Does not check exhaust backpressure.
Gives a quotation without a site survey for a complex installation.
Has unclear warranty conditions.
Cannot provide relevant customer references.
Offers an unusually low price with an undefined scope.

None of these points automatically proves that a vendor is unsuitable, but they are good reasons to ask additional questions before placing an order.

Final Takeaway

Choosing a CPCB-approved RECD vendor should be treated as a technical and compliance decision rather than a simple price comparison. Verify the certification, confirm that the proposed model covers the specific DG engine, review the sizing calculations, understand the installation scope and assess the vendor's service capability.

what RECD they are offeringwhy that particular system is suitable for your generator and how they will support it after installationA reliable supplier should be able to explain not only , but also .

For buyers comparing multiple suppliers, combining CPCB documentation checks with engineering evaluation, site assessment, commercial comparison and customer references provides a much stronger basis for selecting an RECD vendor.

How to Choose a CPCB-Approved RECD Vendor for Your DG Set

RECD For DG Set