Can You Specify an RECD When Original DG Set Documents Are Missing?

Yes, you can. An RECD is specified from technical facts about the engine: its power, its exhaust flow and temperature, its back pressure limit and the space around its exhaust line. Paper documents are the easiest place to find those facts, but they are not the only place. When the invoice, manual and certificates have gone missing, the same facts can usually be recovered from the machine itself, from the manufacturer and from careful measurement.

Missing papers are very common. Generators outlive the people who bought them. Files are lost when companies move offices, when facility managers change, when a building is sold with its equipment, or when a set is bought second hand with nothing but a key. None of this has to stop a retrofit.

This guide is organised as an evidence ladder. We start with what each missing document used to tell the vendor, then climb from the strongest replacement evidence to the weakest, and finish with the separate question of what your Pollution Control Board will expect.

What the Missing Papers Used to Tell Us

Before hunting for replacements, it helps to know what each document contributes to an RECD specification. Some documents matter a lot. Others matter only for compliance.

Missing document	What it told the RECD vendor	How important for specifying the device
Purchase invoice	Date of purchase, model, capacity, supplier	Medium: confirms model and age
OEM operation and maintenance manual	Engine data sheet, exhaust limits, service intervals	High: back pressure limit and exhaust data
OEM test certificate or factory test report	Actual tested output and performance	Medium: confirms real rating
Emission type approval label or certificate	Emission norm the set was built to	High for compliance, medium for device choice
Commissioning report	Installed exhaust layout, initial readings	Medium: baseline back pressure
Consent to Operate	Board’s conditions for the set	High for compliance
AMC and service records	Engine condition and history	Medium: engine readiness

Notice that the single most important engineering input, the permissible exhaust back pressure, usually lives in the manual. That is the document most worth recovering. Everything else can be rebuilt more easily.

The Evidence Ladder

Think of replacement evidence as a ladder. The higher the rung, the more a vendor and a regulator can rely on it. You do not need every rung, but the more you climb, the more precise the specification.

Rung 1: Markings Stamped or Cast on the Machine

Plates can be lost or painted over, but many engines carry permanent identification stamped into the block, cast into a housing or printed on a factory label in a protected spot. Cummins, for example, advises that where the nameplate is unreadable or missing, a serial number may be stamped directly on the generator set, and that the full model, specification and serial number are what a dealer needs to help (Cummins: how to identify your generator model).

Look on the engine block, the alternator frame, the base frame, the turbocharger, the fuel injection pump and the control panel door. Each may carry its own serial or part number. Our guide to DG nameplate photos for an RECD enquiry covers where plates hide and how to photograph them, so we will not repeat that here.

What this rung gives you: engine make, model and serial number. That unlocks almost everything above it.

Rung 2: The Manufacturer’s Own Records

With an engine serial number in hand, the engine manufacturer or its authorised dealer can often retrieve:

• The build specification and rated power.
• The original engine data sheet, including exhaust flow, exhaust temperature and maximum back pressure.
• The emission standard the engine was built to.
• Sometimes the date and destination of dispatch.

Some manufacturers will also supply a replacement copy of the operation manual or a digital version of it. The genset assembler (the company that combined the engine, alternator and enclosure) may hold its own records of the complete set, including the original test report.

What this rung gives you: the engineering data that the missing manual used to hold.

Tip: make the request in writing and ask specifically for the engine data sheet with exhaust parameters. A general request for “documents” often returns a brochure.

Rung 3: Secondary Paperwork Inside Your Own Organisation

Even when the generator file is gone, fragments often survive elsewhere:

• Accounts and fixed asset register. The asset entry usually records purchase date, supplier and value, and sometimes the model.
• Insurance schedules. Equipment insurance often lists the generator with capacity and make.
• Old electrical approvals. Electrical inspection records for the installation may name the set and its rating.
• Previous consent applications. Copies may sit with the environment or compliance team, or with the consultant who filed them.
• AMC contracts and service reports. Service providers record the model and serial number on every visit report. Your current or past service company may still have them.
• Emails and purchase orders. Search the procurement system for the supplier’s name.

What this rung gives you: proof of age, capacity and ownership. Useful for compliance, and a cross-check for the engineering data.

Rung 4: Measurement on Site

When records cannot give you the engineering data, the machine can. A competent survey can measure most of what the vendor needs.

• Actual output. A load bank test shows what the set really delivers at site conditions, which is often more useful than the nameplate figure anyway. Our explainer on how to read generator kVA and kW ratings covers the difference between the two.
• Exhaust back pressure. Measured at the engine outlet under load. This tells the vendor how much headroom is left, which matters more than any figure in a manual. Our post on how exhaust back pressure affects a DG set explains why this number is so important.
• Exhaust temperature. Measured at the proposed device location at different loads.
• Pipe size and flange details. Outer diameter, flange bolt circle, number and size of holes.
• Engine configuration. Number of cylinders, arrangement (inline or V), aspiration (naturally aspirated or turbocharged), and rated speed.
• Running hours. From the hour meter, cross-checked as described in how to check a used generator’s engine hours.

What this rung gives you: real, current data. For the device itself, measured figures are often as good as the missing manual, and sometimes better, because they reflect the actual exhaust route on your site.

Rung 5: Informed Estimation

At the bottom of the ladder is estimation: inferring a figure from similar engines of the same size and type. A vendor might estimate exhaust flow from cylinder count, displacement and speed, or assume a typical back pressure limit for the engine class.

What this rung gives you: a starting point only. Estimation is acceptable for a first budget quotation. It should not be the basis for a final specification if any higher rung is available.

Evidence Ladder Summary

Rung	Source	Reliability	Typical time to obtain
1	Stamped and cast markings	High for identity	Hours
2	OEM and assembler records	High for engineering data	Days to weeks
3	Internal secondary paperwork	Medium, strong for age and ownership	Days
4	Site measurement and load test	High for current condition	One site visit
5	Estimation	Low	Immediate

A Worksheet to Rebuild the File

Copy this into a document and fill it in as you climb the ladder. Note the source of every figure, so anyone reviewing it later knows how it was obtained.

Site and owner

• Site address:
• Owner or tenant:
• Contact person:

Generator identity

• Genset assembler and model:
• Engine make and model:
• Engine serial number (source: plate, stamping, OEM, service report):
• Alternator make and serial:
• Year of manufacture (source):

Rating

• kVA (source):
• kW (source: plate, OEM, load bank):
• Rated speed in rpm:
• Prime or standby rating:

Exhaust

• Pipe outer diameter:
• Flange details:
• Measured back pressure at load (value, load percent, date):
• OEM back pressure limit (source):
• Exhaust temperature at load:
• Silencer type and position:
• Stack height:

Condition

• Hour meter reading:
• Last service date and provider:
• Smoke at load (none, light, heavy, colour):
• Oil consumption observation:

Compliance

• Current Consent to Operate reference:
• Emission norm the set was built to (source):
• Any board correspondence about this set:

A completed worksheet with sources noted is often more useful to a vendor than an old manual, because it describes the set as it stands today.

The Separate Question: What Will the Board Expect?

Specifying the device and satisfying the regulator are two different tasks. A vendor can size an RECD from measurements. Your State Pollution Control Board may still want paperwork that shows what the set is, how old it is and who owns it.

India’s genset rules include type approval, production conformity and labelling requirements, as summarised on DieselNet’s India genset standards page. When the original label and certificate are missing, the board will usually want to see some other evidence of the set’s identity and age.

Things that commonly help:

• The completed technical file with sources, as in the worksheet above.
• Supporting records from Rung 3, especially asset register entries and service reports that link the serial number to your organisation.
• A written declaration from the owner stating the make, model, serial number, capacity and approximate year of manufacture, and explaining how the original documents were lost. Some boards ask for this on letterhead, some as a notarised statement. Ask your board what form it accepts.
• A letter from the OEM or its dealer confirming the engine specification from the serial number.

Requirements differ by state and by case. Ask your board in writing before assuming what it will accept. Our guides on how to get a pollution NOC for a DG set and what happens during a Pollution Control Board inspection show where this paperwork is used. Running a set without the right consent carries real risk, as set out in our post on penalties for running an unregistered diesel generator.

We are not lawyers, and nothing here is legal advice. The point is simply that missing documents are a paperwork problem to solve in parallel, not a reason the device cannot be specified.

Common Situations and How They Resolve

The set came with the building

A company buys a commercial building and inherits a 400 kVA set in the basement. The previous owner took the files. The plate on the canopy is sun-faded, but the engine block still carries a clear stamped serial. The engine dealer confirms the model, rating and back pressure limit from the serial. The building’s own insurance schedule confirms the set was on site at the date of sale.

Outcome: the RECD is specified from OEM data and a site survey. The owner files a declaration with the board, backed by the dealer’s letter.

The facility manager left and the file went with him

A hotel’s generator file cannot be found after a staff change. The AMC company, however, has five years of service reports with the model and serial number on each one, and it still has the commissioning report from installation.

Outcome: the service company’s records fill nearly every gap. This is the quickest recovery of all, which is a good reason to keep your AMC provider’s reports on file.

A second-hand set with no history at all

A small manufacturer buys a used set from a dealer. There is no invoice from the first owner, the plate is missing, and the engine brand is unfamiliar.

Outcome: the survey measures back pressure, exhaust temperature and output on a load bank. The engine brand is identified from cast markings, but no data sheet is available. The vendor specifies the device from measurements, leaving extra margin on back pressure. The owner seeks the board’s view on the set’s status before the installation. If the set also turns out to be imported, the extra checks in our post on retrofitting an RECD to an imported diesel generator apply.

Does Missing Paperwork Change the Device Choice?

Sometimes, in small ways.

• More margin on back pressure. When the engine’s limit is not documented, a vendor may choose a device configuration with lower resistance, or plan the installation to reduce bends, to stay well inside a safe range.
• Rating from measured output. The capacity band is chosen from the load bank result, not from a guess at the original rating.
• Engine readiness checks. Without service history, a quick health check becomes more important. Our post on whether to overhaul an engine before fitting an RECD sets out a simple triage.

What does not change is the device’s own approval. Its test certificate and type approval remain the same regardless of your generator’s paperwork. Our guide on how to read an RECD test certificate explains what those documents contain, and Aceget’s own approvals are listed on our certifications page.

Who Should Carry Out the Measurement Survey?

When Rung 4 is doing the heavy lifting, the quality of the survey decides the quality of the specification. Three parties can be involved, and each brings something different.

• The RECD vendor’s surveyor knows exactly which measurements the device selection needs and where to take them. This is usually the most efficient choice for the engineering side.
• Your AMC or service provider knows the engine’s history and quirks and can run the set safely under load. Having them present during the survey helps.
• A load bank provider supplies controlled, steady load when the site cannot offer enough real load for testing. Without steady load, readings for back pressure and exhaust temperature are less reliable.

For most sites, the simplest arrangement is a single visit where the vendor’s surveyor and the service provider work together, with a load bank if the building’s own load is too low or too variable.

Mistakes That Make a Missing-Document Retrofit Harder

A few common errors turn a manageable paperwork gap into a real problem.

Guessing the rating from the canopy size

Two canopies of the same size can hold engines with quite different power. Always confirm the rating from engine markings, OEM records or a load test.

Relying on the alternator plate

The alternator may have been replaced, or may be rated differently from the engine. The RECD is matched to the engine.

Skipping the back pressure measurement

Without a documented limit, the measured back pressure is your most important safety check. Skipping it removes the one figure that protects the engine from an over-restrictive installation.

Mixing up sets on multi-generator sites

On sites with several similar generators, records from one set are sometimes applied to another. Tag each set with its serial number before the survey and match every document to the right tag.

Creating paperwork that is not accurate

Filling gaps with invented dates or figures to make a file look complete is a serious mistake. It can undermine your credibility with the board and lead to a wrongly specified device. Where a figure is unknown, record it as unknown and state how it will be established.

Waiting for perfect documents

Some owners postpone the retrofit for months while chasing a manual that may never be found. If the engine serial and a site survey give reliable data, proceed with the specification and handle the board’s paperwork in parallel.

Start a New File Today

Once the device is installed, make sure this never happens again. Build a generator file with both a paper copy and a digital copy stored in a shared location. Include:

• The completed technical worksheet.
• OEM letters and data sheets recovered during the process.
• The RECD’s type approval reference, test certificate and installation report.
• Back pressure readings before and after installation.
• Every future service report.
• Your consent documents and any board correspondence.

Our environmental compliance checklist for generator owners is a good template for what else belongs in it. A basic understanding of the parts of a diesel generator also helps whoever inherits the file know what each record refers to.

Frequently Asked Questions

Can a vendor quote without any documents at all?

A vendor can give a budget quotation from photos and a stated kVA rating. A final specification should wait for either OEM data or a site survey with measurements.

Is the alternator plate enough?

Not on its own. The alternator plate shows electrical output, but the RECD is matched to the engine. The engine’s power and exhaust data matter more. Our load calculation basics post explains why electrical and mechanical ratings differ.

Will the OEM charge for records?

Some dealers provide data sheets free; others charge a fee for document searches or replacement manuals. Ask before requesting.

How long does rebuilding a file take?

If the engine serial is readable and the OEM responds quickly, a few days. If everything must come from measurement, allow for one survey visit plus time to analyse the results.

Can the RECD be installed while the board reviews my paperwork?

Ask your board. Some owners prefer to wait for confirmation before spending money. Others install in parallel because the device is required either way.

What if the engine serial number is also unreadable?

Clean the stamping area gently and photograph it with light falling from the side, which often brings faint characters back into view. Check secondary components too, such as the fuel injection pump and turbocharger, whose part numbers can help a dealer narrow down the engine model. If nothing can be read, the specification rests on site measurement, and the board paperwork relies more heavily on your internal records and a written declaration.

Should I replace the missing nameplate once the data is confirmed?

It helps. Once the OEM or dealer confirms the specification, ask whether it can issue a replacement plate or a certified data label. Fixing a clear, durable label to the set makes every future inspection, service visit and resale easier.

Can Aceget help rebuild the technical data?

Yes. Share whatever you have, even just photos, through our contact page. Our team will tell you what is missing, what can be recovered from the engine maker, and what our survey can measure on site before specifying a device from our RECD range.

The Bottom Line

Lost paperwork makes a retrofit slower, not impossible. The RECD is specified from engine facts, and those facts can be recovered from stamped markings, the manufacturer, your own organisation’s records and careful measurement. Climb the evidence ladder as high as you can, note the source of every figure, handle the board’s paperwork in parallel, and then start a proper file so the next person never faces the same hunt.