Aircon Pressure Test in Singapore — Nitrogen Tested, Certificate Issued

When You Need a Pressure Test

Five situations make pressure testing non-negotiable.

New installation handover. Before the system is charged with refrigerant, the pipework holds nitrogen at high pressure for 24 hours minimum. No pressure drop means the joints are sound. Any drop means find the leak before you waste $400 of R32 on a leaky system.

After any brazing or flare work. Repair work that opened the refrigerant circuit always introduces leak risk. Pressure test after repair is the only way to confirm the repair held.

After a refrigerant leak. If your system lost gas and you do not know where, charging it up again is pointless until you find and seal the leak. Pressure test isolates the leak section before the refrigerant goes back in.

Pre-handover inspection for new condos and commercial units. Developers and main contractors often skip or rush this step. If you suspect the installation was not properly tested, an independent test now saves you from years of mystery top-ups later.

MCST and warranty disputes. When the installer claims “no leak” and you keep losing gas, a third-party pressure test with a certificate ends the argument. We have signed certificates that have won MCST defect arbitration for clients.

How We Test (The Actual Procedure)

This is not a 30-minute job. A proper pressure test takes a minimum of 26 to 28 hours from start to certificate.

Step 1: System Isolation and Refrigerant Recovery (1 to 3 hours)

If the system has refrigerant in it, we recover it first using a refrigerant recovery machine into approved cylinders. Recovered refrigerant either gets reused (if clean) or sent for NEA-licensed reclamation. We weigh the recovered amount and document it.

For new installations with no refrigerant yet, this step is skipped.

Step 2: Connection and Initial Pressurisation (30 minutes)

We connect a manifold gauge to the service ports and pressurise the system with oxygen-free nitrogen (OFN) from a calibrated regulator. Pressurisation is staged in three steps to identify gross leaks early:

Any pressure loss during stages 1 or 2 means a major leak exists. We use soap solution and electronic detection to find it before continuing.

Step 3: 24-Hour Hold and Logging (24 hours)

Pressure is held for a minimum 24 hours. We log:

Start pressure and ambient temperature at start. Pressure reading at the 4-hour mark. Pressure reading at the 12-hour mark. End pressure and ambient temperature at 24-hour mark.

Ambient temperature matters. Nitrogen pressure changes about 0.5% per degree Celsius. A 5°C drop overnight will read as a pressure drop that is not actually a leak. We correct for temperature in the final assessment.

Step 4: Leak Investigation if Pressure Drops

A drop of more than 0.3 bar after temperature correction means a leak. We then:

Use electronic leak detector (Inficon GAS-Mate) on every joint, flare, and brazed connection. Apply soap solution to suspect areas. For ceiling void pipework, run section-by-section isolation to narrow the leak to a 3-metre run before opening the ceiling.

Found leaks get repaired (re-flared, re-brazed, or new pipe section) and the test restarts from Step 2.

Step 5: Vacuum Pull and Documentation

After successful test, we pull the system to 500 microns or below using a two-stage vacuum pump, hold for 60 minutes, and verify with a micron gauge.

Certificate is issued listing system address, indoor and outdoor unit models, refrigerant type, pressure stages, hold duration, start/end pressures, ambient temperatures, vacuum micron reading, and lead technician signature.

Pricing

Pricing depends on system type and indoor unit count.

Residential Systems

Commercial / VRV / VRF Systems

Pricing covers the full procedure: nitrogen, manifold connection, 24-hour hold, leak investigation up to 2 hours, vacuum, and certificate. Repair work uncovered by the test is quoted separately at our standard repair rates.

For new installations done by us, the pressure test is included in the installation price — never separate, never optional.

What the Certificate Looks Like

The certificate is one A4 page, signed by the lead technician, with the following on it:

Date and address of test. System inventory: indoor unit and outdoor unit make, model, serial number. Refrigerant type the system is designed for. Pressure test methodology: staged pressurisation, 24-hour hold, OFN used. Pressure readings: start, 4-hour, 12-hour, end. Ambient temperature readings at start and end. Pressure drop calculation, temperature-corrected. Vacuum micron reading and hold time. Pass or fail assessment. Recommendations if applicable (re-test schedule, joints to monitor). Lead technician name and signature. VD Aircon company stamp and contact.

This certificate is accepted by MCSTs, developers, M&E consultants, and insurance assessors for handover and warranty purposes.

Why a Proper Pressure Test Saves You Money

The maths on this is simple. A typical Singapore household with a multi-split system loses about 200 grams to 1 kg of refrigerant per year if there is a slow leak in the pipework. At $90 per kg for R32, that is $18 to $90 a year in gas top-ups, plus the labour call-out for each top-up at $80 to $150 a visit. Across the typical 10-year life of an aircon system, an undetected leak costs $1,000 to $2,400.

A $280 pressure test now, done properly, finds the leak in year one and ends the problem.

For commercial buildings with VRV systems holding 20 to 40 kg of refrigerant, the maths is brutal. A 5% annual leak on a 30 kg system means 1.5 kg of R410A loss per year — about $165 in refrigerant alone, plus the labour, plus the efficiency loss as the system runs undercharged. A $1,300 pressure test pays for itself in two years.

Who Calls Us for Pressure Tests

Property owners after a leak repair done by another contractor — they want independent verification the leak is actually sealed.

Developers and main contractors at TOP handover — we test the M&E sub-contractor’s installation before keys are handed to the buyer.

MCST committees defending against installer warranty disputes — our certificate is admissible at the disputes resolution stage.

Office tenants taking over a fitted-out unit — they want a baseline test before they accept the existing system as their responsibility.

Homeowners renovating who suspect their old contractor cut corners on the original installation — pressure test surfaces what was hidden behind plasterboard.

What Pressure Testing Will Not Tell You

We are direct about the limits. A passed pressure test confirms the refrigerant pipework is sealed. It does not confirm:

The compressor is in good working order. The drainage system is clear. The electrical system is sound. The fan motors are balanced. The system was sized correctly for the space.

For a full system condition assessment, book a diagnostic visit or a VRV/VRF site survey alongside the pressure test. We discount the combined visit by $80.

FAQ

Can the test be done in less than 24 hours if I am in a hurry?

No. A short-duration test misses slow leaks. Pressure drops from a hairline crack take 8 to 16 hours to register against a calibrated gauge. We will not certify a test under 24 hours because the certificate would not be defensible if a leak surfaces later.

Do I need to be home during the 24-hour hold?

No. We pressurise on day one and return on day two for the final reading. The system is safe during the hold — nitrogen at 42 bar is well within pipe pressure rating and no refrigerant is present.

Is nitrogen safe for the system?

Yes. Dry nitrogen is the industry-standard test gas. It is inert, non-flammable, and leaves no residue. It is used precisely because it does not react with copper, brass, or the lubricating oil already in the system.

Will the pressure test damage anything?

No. Test pressure is below the burst pressure of the refrigerant pipe and below the design pressure of the system components. The procedure is safer than charging refrigerant.

My contractor said they did a “pressure test” but it took 10 minutes. Was that real?

No. A 10-minute test detects only catastrophic leaks where you would hear the gas hissing. Slow leaks that lose 0.1 to 0.5 bar over 24 hours require the full hold time to detect. Ten-minute “tests” are theatre, not engineering.

Can I use the certificate for insurance claims?

Yes. Our certificate has been used successfully to support contents insurance claims where refrigerant leak caused damage, and to support installer warranty claims for major repairs. We retain the test data for 5 years and can reissue a certified copy if needed.

Do you do pressure tests on chiller systems?

Yes, but chiller pressure testing follows a different protocol (water-side and refrigerant-side tested separately, condenser tube bundle isolation, oil cooler verification). Quoted per site survey. Call us with your chiller make, model, and capacity for an indicative quote.

Book a Pressure Test

Call 9654 0044 now to schedule a pressure test. Most jobs scheduled within 2 to 4 working days. Urgent same-week slots available for handover deadlines.

VD Aircon Engineering Pte Ltd 11 Mandai Estate #02-04 ELDIX, Singapore 729908 BCA-registered. NEA-registered for refrigerant handling. Test methodology aligned with SS 553.