How to use the finder
Most compressed-air decisions start from one of three places: a job that needs air, a machine you already have or are thinking of buying, or a number you need to work out. The finder is organised the same way:
- Start with the duty. Plant air, drilling, blasting, construction tools, process air, oil-free air, temporary air or a breakdown.
- Narrow by equipment family. Rotary screw, reciprocating, portable diesel, oil-free, centrifugal, blowers or air treatment.
- Pick the question. How it works, how to size it, what goes wrong, how to maintain it or what it costs to run.
- Check the fit. Each row names the duty or family it relates to, so you can tell whether it really fits your case.
- If nothing fits exactly, try the neighbouring duty or equipment family. Many problems sit between two families, such as low pressure caused by distribution rather than the compressor.
When the pages answer your question but you still need a machine, a quotation or a diagnosis, use the enquiry links at the end of each section.
Find by duty: what do you need the air for?
| Duty | Typical pressure | Start here |
|---|---|---|
| Factory plant air and tools | About 6–8 bar (87–116 psig) | Rotary screw compressors |
| Workshops, garages and small users | About 7–12 bar (101.5–174 psig) | Reciprocating compressors |
| Construction breakers and rock drills | About 7 bar (101.5 psig); 85–145 cfm per tool | Portable air compressors |
| Borewell and DTH drilling | About 14–28 bar (203.1–406.1 psig); special units up to 35 bar (507.6 psig) | Borewell and DTH compressor library |
| Abrasive blasting | About 7 bar (101.5 psig) at the nozzle | Blasting air demand calculator |
| Pharma, food, electronics, medical | Varies; air purity is the deciding factor | Oil-free compressors |
| Large, steady base-load air | Varies by process | Centrifugal compressors |
| Shutdowns, projects and breakdown cover | Rental fleet 2–30 bar (29–435.1 psig) | Temporary air engineering |
Pressures are typical starting points. The pressure that matters is the one needed at the critical point of use, plus the losses in hoses, filters, dryers and pipework between the compressor and that point.
Find by equipment family
If you already know the type of machine, go straight to its hub. Each hub explains how the technology works, where it fits, how to select it, how it is maintained and what usually goes wrong.
- Types of air compressors: the overview of every family and how they compare.
- Rotary screw compressors: fixed and variable speed, air and water cooled, oil-injected plant air.
- Reciprocating compressors: single and two-stage piston, high-pressure, booster and PET blowing duties.
- Portable air compressors: diesel and electric site machines, typically 100–600 cfm, with larger drilling packages above that.
- Oil-free compressors: dry screw, water-injected, scroll, tooth and oil-free piston machines and ISO 8573-1 Class 0 air.
- Centrifugal compressors: single and multi-stage, integrally geared, plant-air and process machines.
- Blowers vs compressors: when low-pressure air is better served by a blower.
- Used and refurbished compressors: buying a pre-owned machine and what to check.
Deciding between two families? The rotary screw vs reciprocating comparison and the stationary vs portable screw comparison cover the most common choices.
Find by question: which calculation do you need?
Our knowledge and calculation centre holds calculators and worksheets. Each tool page explains its inputs, method and limits. Common starting points:
| Question | Tool | What you need to enter |
|---|---|---|
| How much air do my tools and machines need? | Compressed air demand calculator | Each user’s consumption, quantity and how often it runs at the same time |
| What size pipe do I need? | Pipe sizing calculator | Flow, pressure, pipe length and allowed pressure drop |
| How big should my receiver be? | Receiver transient storage calculator | Peak demand, duration and allowed pressure band |
| How does FAD convert between reference conditions? | FAD conversion tool | Flow, inlet pressure, temperature and humidity basis |
| Which machine uses less energy? | Specific power comparison | Input power in kW and delivered flow in m³/min at the same pressure |
| Is renting or buying better for my job? | Rental vs ownership calculator | Purchase price, monthly hire charge, monthly running cost under hire, monthly running cost if owned, and months of need |
| How much air is lost to leaks? | Leakage scenario calculator | Leak flow estimate, running hours and specific power |
A calculator is only as good as its inputs. A demand figure based on nameplate tool consumption, for instance, ignores wear, leaks and the real pattern of simultaneous use. Where the decision is expensive, measure before you commit. Logging flow and pressure over a normal production week is usually the most reliable starting point for any sizing decision.
Find by problem: what is going wrong?
When a system is not performing, the symptom rarely tells you the cause directly. These pages help you narrow it down:
- Machine stopped or tripping: breakdown diagnostics and fault triage.
- Water or oil in the air: dryer service and dew-point performance.
- Pressure falling at the point of use: pipe network pressure drop and leak management.
- Diesel portable not making pressure or overheating: diesel portable troubleshooting.
- High energy bills: system audit and benchmarking.
A typical oil-injected screw compressor discharges at about 75–95 °C. Above that range, check cooling, ventilation and oil level before assuming the airend is at fault. Every extra bar of generation pressure costs roughly 7% more power, so raising the set point to cure a distribution problem is usually the expensive answer.
Find by need: service, parts and maintenance
| Need | Engineering page | Enquiry page |
|---|---|---|
| Planned maintenance | Preventive maintenance | Service and maintenance enquiry |
| Annual maintenance contract | Compressor AMC | Service and maintenance enquiry |
| Screw compressor servicing | Rotary screw service | Service and maintenance enquiry |
| Spare parts | Spare parts hub | Spare parts identification enquiry |
| Temporary air | Temporary air engineering | Temporary air hire enquiry |
| Energy and air audits | System audit | Audit and measurement enquiry |
Find by location
Our service teams cover the whole of Telangana and Andhra Pradesh from our office in Tarnaka, Secunderabad, and we supply compressors, rentals and spares across India. Regional pages explain local conditions such as summer ambient heat above 45 °C, dust on construction and drilling sites, and the industrial areas we support:
What the finder will not do
- It does not size or select a compressor for you. Selection needs your flow, pressure, air quality, duty pattern, power supply and site conditions.
- It does not confirm that a part fits your machine. We confirm fit from the make, model, serial number, nameplate photo or old part before quoting.
- It does not give prices or availability. Those depend on the machine, the duty and the timing, and are confirmed in a quotation.
- It does not diagnose a fault with certainty. Use it to understand likely causes, then send us readings and photos.
How Reddy Compressors helps
Behind every page is a working business. Reddy Compressors, serving industry since 2002 from Tarnaka, Secunderabad, sells new and used/refurbished compressors, rents from its own fleet of 50–2,000 cfm and 2–30 bar diesel and electric machines, services and overhauls, carries out air audits and supplies spare parts. We are an independent multi-brand specialist working on ELGi, Atlas Copco, Ingersoll Rand, KAESER, Chicago Pneumatic, Doosan, Kirloskar and other makes, not an authorised dealer. We have tie-ups with all major and reputed brands. We also sell, rent and service gas compressors, centrifugal compressors and blowers. Over 20 service engineers and technicians cover Telangana and Andhra Pradesh, and we supply across India. If the finder leaves you between options, a service engineer will help you choose.
What to send us
- What the air is for, and the pressure needed at the critical point of use.
- Estimated or measured flow, and how demand changes through the day.
- Air quality needed: dry, oil-free or a stated ISO 8573-1 class.
- Power available (voltage, phase, supply capacity) or whether diesel is required.
- For existing machines: make, model, serial number and a nameplate photo.
- Site location and whether you need purchase, rental, service or parts.
Frequently asked questions
Which type of air compressor do I need for my factory?
Most factories with steady demand at about 6–8 bar (87–116 psig) use oil-injected rotary screw compressors, while small or intermittent users often suit a reciprocating machine. Oil-free machines are chosen where air touches product, as in pharma or food. The right answer depends on flow, pressure, air quality and duty pattern, so start with the demand calculator and send us the result.
How do I calculate how much compressed air I need?
List each air user, its consumption at the working pressure and how often it runs at the same time as the others, then add an allowance for leaks and future growth. Our compressed air demand calculator explains the method. For an existing plant, logging actual flow and pressure over a normal production week gives a far more reliable figure than nameplate values.
What compressor do I need for a borewell rig?
Borewell and DTH drilling typically needs 600–1,500 cfm at about 200–400 psig (13.8–27.6 bar), with special units up to about 35 bar (507.6 psig). The right size depends on hole diameter, depth, hammer and ground conditions. Our borewell and DTH compressor library explains the selection, and we supply all types, brands and models: new, used, rental, service and spares.
Can the finder recommend a specific compressor model?
No. The finder points you to explanations and tools that help you understand your options. A model recommendation needs your flow, pressure, air quality, power supply, site conditions and duty pattern, checked by a service engineer. Send us those details and we will propose suitable machines from the brands we sell, rent and service, new or used.
Where can I find compressed air calculators?
Our knowledge and calculation centre has calculators and worksheets for demand, pipe sizing, receiver storage, FAD conversion, specific power, leak cost, rental versus ownership and more. Each tool page explains what it calculates, the inputs, the method, a worked example and its limits, so you can judge how far to rely on the result before acting on it.
What should I do if I cannot find the page I need?
Call +91 99590 60718 or +91 92468 88812, send a WhatsApp message, or email reddycompressors@gmail.com with a short description of your duty or problem. A service engineer will point you to the right information or, if your question needs your own data, tell you what to send so we can review it properly.
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.