AC Nitrogen Leak Test Explained
Last updated: 29 October 2026
Before refrigerant is charged into an AC, the refrigerant circuit should be checked for leaks. A nitrogen pressure test is the usual way to do it. This guide explains what the test is, how we carry it out, and when it is charged separately.
What is a nitrogen pressure test?
In a nitrogen pressure test, the refrigerant circuit of the AC is pressurised with dry nitrogen at the manufacturer specified test pressure. The technician then checks the circuit for leaks. It lets a leak be found and repaired before any refrigerant goes in, so the gas is not wasted.
Why do we test for leaks before refilling gas?
If an AC is low on gas, the gas has usually leaked out somewhere. Refilling a leaking system only wastes refrigerant and money, and the cooling falls again after a while. For this reason nitrogen pressure testing and leak inspection are recommended before refrigerant charging, and we do not charge refrigerant into a system with a known, unresolved leak.
Our service procedure, step by step
1. Initial inspection: Check the AC cooling performance, operating pressure and visible signs of refrigerant leakage.
2. Nitrogen pressure testing: Pressurise the refrigerant circuit with dry nitrogen at the manufacturer specified test pressure to check for leaks.
3. Leak detection: Inspect accessible joints, flare connections, piping and other relevant components using suitable leak-detection methods.
4. Leak repair: If a leak is found, it is repaired only after your approval. Repair charges and materials are extra.
5. Evacuation: Evacuate the system with a vacuum pump when the service procedure requires it, so that moisture and non-condensable gases are removed.
6. Refrigerant charging: Charge the correct refrigerant type and quantity as per the manufacturer specifications.
7. Final performance check: Check cooling performance, operating parameters and overall system operation.
Safety rules we follow
- Nitrogen pressure never exceeds the manufacturer specified test pressure
- Oxygen or compressed air is never used for pressure testing of the refrigerant circuit
- Refrigerant is not charged into a system with a known, unresolved leak
Is nitrogen testing charged separately?
Nitrogen testing and leakage repair charges may be additional unless they are specifically included in the approved quotation. Gas refilling, nitrogen testing, leakage repair, vacuuming and refrigerant costs are itemised in the quotation as applicable, and no additional work is done without your approval. All prices are exclusive of GST. For rates, read the AC gas refilling price guide.
What you receive after the job
After each job we share a digital service report with before and after cooling readings, the nitrogen leak-test result where applicable, the name and quantity of the refrigerant used, parts and labour charges, and the technician report and invoice. Gas refilling carries a 3-month warranty. If the same leak reappears within that period, we come back and address it.
Book a leak test and gas refill in Pune
Call or WhatsApp us to book a visit. Our visiting and diagnosis charge starts from ₹249, and the final cost is confirmed on-site before any work begins. See the AC gas refilling service page or the AC gas refilling price guide.