Will Installing an RECD Affect My Generator’s OEM Warranty?

Almost every generator owner who hears the words “retrofit emission control device” asks the same second question: “If I bolt this onto my exhaust, will the engine maker still stand behind the engine?”

It is a sensible worry. A diesel generator is a large purchase, the warranty is a real asset, and nobody wants to trade a compliance problem for a coverage problem. Yet the answers you find online tend to be either reassurance (“No effect at all!”) or alarm (“Any modification voids it!”). Neither is accurate, because warranty is not a single switch. It is a bundle of promises with conditions attached, and an RECD interacts with those conditions in specific, predictable places.

This guide maps those places. It uses the picture of a relay race, with the engine maker running the first leg and the RECD supplier running the second. Most of the risk sits in the short stretch where the baton is passed. Once you know where that stretch is, you can make sure the handoff is clean.

The short answer

Installing an RECD does not automatically void an OEM warranty. What matters is who installs it, whether the device is properly approved and correctly sized for your engine, whether the installation and back pressure are documented, and whether a later failure can reasonably be linked to the device. Some engine makers, including Kirloskar and Cummins, sell RECDs for their own sets, which shows that retrofitting is not inherently incompatible with a warranted engine. But you should still get the OEM’s position in writing, because your warranty is a contract and the exact wording of your own document decides the matter.

Warranty is a relay race, not a switch

Think of your generator’s life after retrofit as two runners.

Runner One is the engine and generator manufacturer. Their promise covers defects in material and workmanship in the engine and alternator, for a stated period and under stated conditions.

Runner Two is the RECD supplier. Their promise covers the device itself: the housing, catalyst or filter elements, sensors if any, and its performance, again for a stated period and under stated conditions.

The mistake most owners make is to assume that one warranty flows smoothly into the other. It does not. Each runner is responsible for their own leg, and neither promises the stretch that lies between. That stretch is the exchange zone, and it is where disputes are born.

Runner One: what an OEM warranty actually promises

Reading your own warranty document is the single most valuable step you can take. As an example of how such terms look in practice, consider the published terms from Kirloskar’s warranty service page. They state that the warranty covers defects in material and workmanship under normal use, and they give durations for green gensets of 30 months from invoice or 24 months from installation, whichever comes first. They also attach conditions that many owners overlook:

• Use of genuine parts, oil, filters and coolant.
• Maintenance through authorised service centres, following the preventive maintenance schedule, with the first service within 50 hours or one month.
• Registration of the engine, since the warranty is offered only on registered engines.
• Exclusions for unauthorised modifications, non-genuine parts, improper installation and commissioning, mishandling, normal wear and consequential damages.

This is one manufacturer’s wording, and other makers write theirs differently, so treat it as an illustration and not a universal rule. The important pattern is that OEM warranties usually protect the engine against defects and exclude damage caused by things the maker did not approve or control. An exhaust after-treatment device is something an OEM may or may not consider “approved,” and that is precisely why you want to ask.

Runner Two: what the RECD supplier promises

The RECD has its own warranty, and it is worth reading with the same care. To see what is typical, look at how an engine maker presents its own device. Kirloskar’s RECD product page describes a one-year warranty as part of a package that includes supply, installation, testing and handover, low back pressure within permissible limits, and a maintenance interval of about every six months or 500 hours. Cummins, in its announcement of an RECD for its own gensets, says the device is fitted after the silencer with no modification to the existing exhaust, captures particulate matter at more than 70 percent efficiency, and is designed with minimal back pressure to protect the engine.

When you assess any supplier’s warranty, look for these items in writing:

• Duration and start date. Does it start at invoice, commissioning or handover?
• What is covered. The housing, the catalyst or filter substrate, the sensors, the mounting hardware, and the labour to replace a defective part.
• What is excluded. Common exclusions include poor fuel, excessive engine oil consumption, missed maintenance and damage from an unrelated engine fault.
• Performance backing. Is there a declared back pressure at rated load, and does the supplier commit to a measured value at commissioning?
• Service arrangements. Who attends a fault call, within what time, and in which cities?

The regulatory background matters too, because it explains why the device must meet a recognised standard. The Maharashtra Pollution Control Board circular on RECDs, summarised by TeamLease RegTech, requires certification by one of four CPCB-approved test agencies and a minimum 70 percent particulate reduction without worsening other emission parameters. A device with proper type approval has at least been tested against a common yardstick, which supports any later argument that it was suitable for your engine.

The exchange zone: five places the baton can drop

The two warranties can each be perfectly fair and still leave you exposed in the space between them. There are five typical trouble spots.

1. Back pressure

An RECD sits in the exhaust path, so every exhaust gas molecule has to pass through it. That adds resistance. Engine makers specify a maximum permissible exhaust restriction, and if the total system exceeds it, the engine can lose power, run hotter and stress the turbocharger. Our explainer on exhaust back pressure in DG sets covers the mechanics. From a warranty view, back pressure is the number that most often connects an RECD to an engine complaint, so it is the number you most want on record.

2. Installation quality

Weight on the wrong supports, an unsupported flexible bellow, a sharp new bend or a poorly sealed flange can all cause problems that appear months later. If the device was fitted by someone whom the OEM does not recognise, the OEM can argue that improper installation caused the fault. The remedy is a documented, competent installation. See our guide on the RECD installation process and the list of common RECD installation mistakes to avoid.

3. Soot and oil carry-over

A healthy engine passes little oil into the exhaust. A worn one passes more, and it can foul an RECD. When that happens, the RECD supplier may point to the engine (“your engine is burning oil”), while the engine maker may point to the device (“your RECD is choking it”). Baseline readings before installation are the best protection against that argument.

4. Sensors and controls

Some RECDs carry pressure or temperature sensors, and some sets have alarms wired to them. If a sensor is connected to an engine control input or a panel alarm, the wiring itself becomes a modification. It needs to be done cleanly and recorded.

5. Nobody owns the diagnosis

When the set trips or loses power, two vendors arrive and each looks for reasons the problem is not theirs. Without measurements, the owner is the one left waiting. This is why agreed diagnostic steps, such as who measures back pressure and at which point, are worth settling before anything goes wrong.

How a warranty dispute is actually decided

When a claim is filed, the manufacturer’s service engineer does not usually ask, “Is there an RECD on this set?” and stop there. The more useful question, from their point of view, is: “Is the failed part connected to the modification, and did the modification plausibly cause the failure?”

That is a question of causation. Consider what a service engineer will look at:

• Which part failed? Parts linked to the exhaust side, such as the turbocharger, exhaust valves or manifold, will attract more scrutiny than an alternator bearing or a fuel injection pump.
• What do the records show? Was back pressure measured before and after installation? Was the set serviced on schedule with the right consumables?
• Does the failure pattern point to restriction? Overheating exhaust temperature, poor load acceptance and turbocharger damage are typical patterns of excessive restriction.
• Was the device installed by a competent party and to the supplier’s instructions?

In some countries, the law expressly limits a manufacturer’s ability to void a warranty solely because an aftermarket part is present. A widely quoted example is US law, and industry guidance such as that from Turnkey Industries on what voids industrial generator warranties notes that manufacturers generally cannot void coverage over aftermarket parts unless those parts caused the failure. That is a United States rule. It should not be assumed to apply in India, where the outcome depends mainly on the contract terms and on general consumer law. If you face a real dispute, take advice from a lawyer who handles consumer or commercial disputes, and do not rely on a foreign rule as a shield.

The practical lesson is the same in every jurisdiction: records win arguments. An owner with clear before-and-after data and a documented installation is in a far stronger position than one with a story.

Five ways the baton drops in real life

The table below sets out five illustrative situations. They are examples of how such cases tend to unfold and not a prediction of any specific outcome, because the result always depends on the warranty wording and the facts.

Situation	Likely stance	Reasoning	What would have helped
Turbocharger fails ten months after RECD installation, and no back pressure record exists	OEM may decline, citing an unapproved modification	Turbo is exhaust-side, and no data shows the exhaust restriction was within limits	Back pressure recorded at commissioning and at the first service
Alternator bearing fails during warranty	Normally unaffected by the RECD	The alternator is electrically and mechanically separate from the exhaust	Nothing beyond routine service records
Exhaust manifold cracks after the RECD was mounted with unsupported weight on the flange	OEM may treat it as installation damage	Improper installation is a common exclusion	Installation by a competent team with proper supports, and a sign-off sheet
RECD clogs early because the engine is burning oil due to worn rings	RECD supplier may decline, citing engine fault	Device warranties typically exclude damage from another component’s defect	A pre-installation health check that records oil consumption
Coolant leak causes overheating, unrelated to the exhaust	Not linked to the RECD	The failure has no path to the exhaust system	Regular servicing, kept on record

Look at the right-hand column. In every case, what would have helped is a document, a measurement or a competent installer, not a legal argument.

Is your generator still in warranty at all?

Before worrying about the exchange zone, check whether you are in it. Warranty periods for gensets are typically counted in a few years. The Kirloskar example above is 30 months from invoice or 24 months from installation, whichever occurs first. Retrofit requirements, on the other hand, are usually aimed at sets that have been running for some time. The MPCB circular summarised earlier, for example, applies its requirement to engines that are at least five years past their manufacture date. In that framework, many sets that need an RECD are already outside their original warranty.

Read your own set’s paperwork, though, because regional rules differ and some owners hold extended warranties or long-term service agreements. If you are inside a warranty window, you have three sensible routes.

Route A: fit an OEM-supplied RECD. If your engine maker sells an approved device for your model, the warranty conversation may be the simplest. Kirloskar publishes an RECD for its sets in the 125 to 1000 kVA range, and Cummins offers one for its own gensets. Check current availability for your exact model.

Route B: fit a third-party RECD with the OEM’s written acknowledgement. Write to the OEM or its authorised dealer, describe the device and its approvals, and ask for their position in writing. A template for that letter appears below.

Route C: wait for the warranty to end, if the law allows you to wait. This only works if your compliance deadline allows it. Legal obligations should not be ignored for the sake of a warranty. Operating a non-compliant set carries its own consequences, described in our articles on penalties for running a non-compliant DG set and on DG sets sealed for non-compliance. For the regulatory picture, see why an RECD is mandatory in India and our page on DG set emission regulations.

The clean handoff: a step-by-step plan

Here is a practical sequence that keeps both warranties intact as far as one reasonably can.

1. Read the warranty document end to end. Highlight conditions on modifications, approved service providers and maintenance intervals.
2. Ask the OEM or dealer in writing. State the engine model and serial number, the device model and approvals, and ask whether they have any requirement or objection. Keep their reply.
3. Choose a properly approved device. Verify CPCB type approval and test documentation. Our guides on how to choose CPCB-approved RECD vendors and how to verify a CPCB tested RECD walk through it.
4. Give the vendor accurate engine data. A sizing based on the wrong engine detail is a weak foundation. See our guide on DG nameplate photos for RECD enquiries.
5. Get the vendor’s declared back pressure in writing, at rated load, and agree how and where it will be measured after fitting.
6. Capture a baseline before installation. Record back pressure, exhaust temperature, load performance, visible smoke, oil consumption and running hours. Photograph the exhaust path.
7. Inform the OEM’s service team about the date of installation, and invite their representative to witness commissioning if practicable.
8. Measure again after commissioning, at the same points and loads. Sign the sheet together with the installer.
9. Keep servicing on schedule, using genuine consumables and authorised service where your warranty requires it. Our comparison of in-house maintenance and AMC can help you decide who does that work, and our guide to negotiating an AMC contract covers what to ask an AMC provider to commit to.
10. Maintain the RECD as specified. Follow the cleaning and regeneration routine in our RECD maintenance guide and log each visit.
11. Build a warranty folder. Store the OEM letter, RECD certificate, installation report, before and after readings, photos and service logs together. If a claim ever arises, you will be glad to have it.

A letter you can adapt for your OEM dealer

Copy the text below, fill in the brackets and send it by email so you have a dated record.

To: [OEM dealer or service head]
Subject: Retrofit emission control device on DG set [serial number]

Dear Sir or Madam,

Our DG set details are:
Genset model and kVA: [ ]
Engine model and serial number: [ ]
Date of commissioning: [ ]
Warranty status and end date as per our records: [ ]

We plan to fit a CPCB type approved retrofit emission control device (RECD) to meet emission compliance requirements. Device details:
Supplier: [ ]
Model and capacity band: [ ]
CPCB type approval reference: [ ]
Declared exhaust back pressure at rated load: [ ]
Installation to be carried out by: [ ]

Please confirm in writing:
1. Whether the installation of this device affects the warranty on the engine and alternator, and under what conditions.
2. Any maximum exhaust back pressure or other technical requirement we must meet.
3. Whether you would like to witness commissioning.
4. Any documentation you need from us afterwards.

Thank you.
[Name, designation, phone, email]

Two outcomes are common. The dealer either replies with conditions, which you can then build into your plan, or replies vaguely. If the reply is vague, ask again with a more specific question, and if it remains vague, note the dates on which you asked. Your effort to be transparent is itself evidence of good faith.

Questions to put to the RECD vendor

Vendors can promise many things in conversation. What matters is what they will sign.

• What is the warranty on the device, when does it start, and what is excluded?
• What is the declared back pressure for my engine model and rating, and will you measure it at commissioning?
• If my OEM raises a concern, will you provide the technical file, test reports and type approval documents to support us?
• Who attends a fault call, and how fast?
• Will you stand behind consequential engine damage that is shown to be caused by your device? Many suppliers will decline this, but you should know the answer before you sign.
• What maintenance does the device need, and does that maintenance need to be done by you to keep the warranty valid?

Our team is happy to answer these questions for our own installations, and you can put the same list to any other vendor you are considering.

Red flags in warranty talk

• “It will never affect your warranty, guaranteed.” Nobody can promise an outcome they do not control. Ask for that in writing, and see whether the language survives.
• No back pressure figure. If a vendor cannot state the value for your engine, they may not have sized the device properly.
• Reluctance to share type approval documents. Approvals are the baseline of trust.
• No installation record. A device fitted without a sign-off sheet and readings leaves you defenceless later.
• Warranty that starts before you receive the device. Look at the start date.

Warranty versus compliance: which wins?

Sometimes owners feel forced to pick between them. In practice, the law is not something you can trade off against a warranty. If your set falls within a mandate, you need to comply. Your job is to comply in a way that leaves the warranty in the best possible shape. That is what the steps above are for: the right device, the right installer, the right paperwork and the right conversation with your OEM.

Frequently asked questions

Does an RECD automatically void my generator’s warranty?

No. There is no automatic rule. The outcome depends on your warranty wording, who installed the device, whether it is properly approved and sized, and whether a later failure can reasonably be tied to it. Ask the OEM in writing and keep records.

Should I install the RECD before or after the warranty ends?

If the law allows you to wait, some owners choose to install after the warranty period. But compliance deadlines and enforcement come first, so never delay a legally required retrofit only to protect a warranty. If you must install during the warranty period, follow the clean handoff steps.

What if the OEM refuses to give me a written opinion?

Record the date and method of each request, and keep any replies. Choose a device with a clear approval and back pressure statement, install it competently and document everything. A dealer’s silence does not prove that they will deny a claim, but your records will help if one is contested.

Who is responsible if the engine is damaged by the RECD?

It depends on the cause, the wording of both warranties and the installation records. If the device or its installation caused the damage, the supplier or installer may be responsible, but many device warranties limit or exclude consequential engine damage. Ask about this before purchase.

Does the OEM warranty cover the RECD itself?

Usually not, unless the OEM supplied the RECD. The device carries its own warranty from its supplier, so read that separately.

Will an RECD reduce my engine’s performance?

A correctly sized device is designed to keep back pressure within permitted limits, so it should not noticeably affect performance. That is why measured back pressure before and after installation matters. If the reading exceeds the engine’s limit, performance can suffer, and that is exactly the situation a warranty dispute is likely to revolve around.

What if I have an AMC with a service company instead of the OEM?

Your AMC provider may have its own terms about modifications and its own view of the RECD. Involve them early, and ask them to acknowledge the installation. If the AMC includes the RECD in its scope, get that written into the contract.

Talk to us before you commit

If you are planning an RECD and want to think through the warranty position, share your engine details and warranty status with our team and we will help you plan the documentation and the handoff. Explore capacity-specific options on our retrofit emission control device page or contact us through the contact page.

Renting rather than owning? The warranty question looks different when the machine belongs to someone else. Our guide on installing an RECD on a rented diesel generator covers that case.