Start with the question, not the files
Before attaching anything, write one or two sentences that state the decision you need. “Our 75 kW screw compressor trips on high temperature every afternoon in May; we need the cause and a fix” is far more useful than a folder of fifty unlabelled photos. The question tells our engineers which data matters and which can wait.
Then give the context: the site and town, the industry, how many compressors and dryers are installed, and whether the issue is a breakdown, a planned change, a hire requirement or a parts need. A clear question and context cut down the follow-up calls.
Order of importance
- The question, and the site and equipment context.
- Equipment identity: nameplate photos, model and serial numbers, drawing numbers and revisions.
- Operating evidence at the point of the problem: pressure, flow, temperature, dew point, power and alarms.
- History: service records, recent changes, fault logs and earlier reports.
- Supporting material: layouts, piping sketches, photos of the plant room and videos of the fault.
If time is short, send items 1 and 2 first. They let us start, and the rest can follow.
Equipment identity
For each compressor, dryer, filter, receiver or blower involved, photograph the nameplate straight on and readable. Add the controller’s information screen if it shows model, hours and software version. Note running and loaded hours, the year of installation, and anything changed since: a new motor, a replaced airend, a different oil or a modified control setting. For portable diesel units include the engine make and model and its hour meter reading.
Include the air treatment and storage too. Note each dryer’s type and rating, each filter’s grade and housing size, the receiver volume and its working pressure, and the drain type. Many apparent compressor problems, such as low pressure or wet air, actually start in a blocked filter, an undersized receiver or a failed drain, and these details let us see that early.
How to report measurements
Every number needs four things: the value, the unit, where it was measured and the time. Without those, readings can be misread or compared wrongly. The table shows what to record for the most common data.
| Measurement | Record with it | Common mistake |
|---|---|---|
| Pressure | bar(g) or psig, gauge location (compressor discharge, after dryer, header, point of use), load state | Mixing gauge and absolute, or not saying where the gauge is |
| Flow | m³/min or cfm, whether free air delivery or measured, reference conditions, meter type | Quoting the nameplate rating as actual demand |
| Power | kW, voltage, current, power factor, logging interval | Using motor nameplate kW as running power |
| Temperature | °C at discharge, oil, cooling air in and out, room ambient | Ambient measured in a cool office, not the plant room |
| Dew point | Pressure dew point in °C, instrument type, sampling point | Confusing pressure dew point with atmospheric dew point |
| Running hours | Total and loaded hours from the controller, date read | Reading only total hours, which hides unloaded running |
Use one unit system throughout a document where you can. If you must mix, say so. For reference, 1 bar is 14.5 psi, and 1 m³/min is about 35.3 cfm.
Pressure, flow and power data
Pressure readings are most useful as a set taken at the same moment: compressor discharge, after the dryer and filters, at the main header and at the problem end use. The differences show where pressure is being lost. A single gauge reading at the compressor tells us very little about a low-pressure complaint at a machine 200 metres away.
Flow is rarely metered in Indian plants, and that is fine; say so. An estimate from loaded hours, a list of air users with their consumption, or a short logging exercise is better than a guess presented as fact. Power logs with time stamps, ideally at one-minute intervals or shorter over a full production cycle, show load and unload behaviour and help calculate specific power in kW per m³/min. If you have energy-meter data, export it with the meter location and the time base.
Temperature, dew point and air quality
For heat-related trips, give the discharge temperature at the time of the alarm, the plant room temperature and whether doors, ducts or fans were open. In Telangana and Andhra Pradesh summers, plant rooms can run far hotter than outside air if hot cooling air recirculates, and that is often the real cause. A normal oil-injected screw discharge runs at about 75–95 °C; readings well above that need explaining.
For moisture or contamination complaints, report pressure dew point with the instrument type and where the sample was taken, the dryer type and its settings, and the air-quality class you need under ISO 8573-1 if you know it. Photos of the drain discharges and of wet or oily filters help greatly.
Logs, records and photos
- Controller fault and event logs exported or photographed, with the date shown.
- Service reports, especially the last two or three, with parts changed.
- Trend data in spreadsheet form (CSV or XLSX) rather than screenshots of graphs.
- Photos with something for scale and a note of what each one shows.
- Short videos for noises, vibration or cycling problems, with sound on.
- Drawings or sketches with the revision and date, marking the problem area.
Evidence for special enquiries
Some enquiries need specific data. For borewell and DTH drilling, give the hammer size, bit diameter, expected depth and formation, and the pressure and flow the rig and hammer need, which typically fall in the 600–1,500 cfm range at 200–400 psig (13.8–27.6 bar). For temporary air hire, give the job, the duration, the hours per day, site access and power supply. For audits, say which compressors, dryers and areas are in scope and what logging is allowed. For spare parts, the nameplate and photos of the old part with measurements are what matter most.
Files, naming and privacy
PDF, JPG, PNG, CSV, XLSX and common video formats are all fine. Name files so they make sense on their own, for example “C2-nameplate.jpg” or “header-pressure-12-May.csv”, and group them by machine. Large videos are better shared by a link.
Share only what is needed. Remove personal details of staff, unrelated commercial terms and anything security-sensitive such as network passwords for remote monitoring. If a drawing is confidential, tell us, and send only the part that is relevant.
When data is missing or does not agree
Missing or conflicting data is normal, and it is not a reason to delay an enquiry. Tell us what you do not know. If a reading looks wrong, for example a dew point that cannot be right for the dryer type, we will say so and suggest a check. Where it matters, our engineers measure on site rather than rely on uncertain readings, and our recommendations state which figures were measured and which were estimated.
How Reddy Compressors helps
Reddy Compressors, based at Tarnaka, Secunderabad, has worked with industrial compressed air since 2002. Our engineers review submitted data for sales, rental, service, audits and spare parts across all major brands, including ELGi, Atlas Copco, Ingersoll Rand, KAESER and Chicago Pneumatic, as an independent multi-brand specialist. Where the data raises more questions than it answers, one of our 20-plus engineers and technicians can visit sites anywhere in Telangana and Andhra Pradesh to measure and inspect. Equipment, rentals and spares are supplied across India.
What to send us
- A one- or two-line statement of what you need decided
- Site, industry and a list of the equipment involved
- Nameplate photos and running hours
- Labelled readings: value, unit, location and time
- Recent service reports and fault logs
- Your contact name, phone and the best time to call
Frequently asked questions
What information does a compressor engineer need to diagnose a problem?
Start with what the problem is and when it happens, then the nameplate details and running hours of the machine. Add pressure readings at the compressor and at the point of use, the discharge temperature, the plant room temperature and any alarm messages. Recent service reports help a lot. With these, an engineer can usually narrow the cause before visiting and bring the right parts and tools.
How do I measure the air consumption of my factory?
The most reliable way is to install a flow meter on the main header and log it over a full production cycle. Without a meter, loaded hours and load/unload timing from the compressor controller, combined with the machine’s rated free air delivery, give a reasonable estimate. A list of air users with their rated consumption helps check it. Our audit team can carry out power and flow logging if you need measured figures.
What is the difference between pressure dew point and atmospheric dew point?
Pressure dew point is the temperature at which water condenses in the compressed air at its working pressure. Atmospheric dew point is the same air expanded to atmospheric pressure, which gives a much lower figure. Dryers are rated by pressure dew point, for example about +3 °C for a typical refrigerated dryer, so always say which one your instrument shows.
Can I send compressor data on WhatsApp?
Yes. Photos of nameplates, gauges, alarm screens and short videos sent on WhatsApp to +91 99590 60718 are a quick way to start. For longer logs, spreadsheets and drawings, email is better because files keep their quality and names. Add a short note to each photo saying what it shows and where it was taken, so nothing is misread.
Should I send the compressor manual with my enquiry?
Not usually. We need the nameplate, model and serial number, which identify the manual we need. Do send pages you have marked up, such as a modified wiring diagram or a site-specific settings sheet, because these show how your machine differs from standard. Your own service records and fault logs are more valuable than the standard manual.
Related pages
Technical content reviewed by D. Srinivas Reddy, Managing Partner and service engineer, Reddy Compressors. Last updated 17 October 2026. How our engineering content is reviewed.