Refrigerant Leak Detection
Found, repaired, pressure tested and proven — not topped up and revisited next quarter.
Daikin VRV, Mitsubishi City Multi and LG Multi V.
If your system has been topped up, you have a leak
Refrigerant is not consumed. It is a sealed circuit, and nothing burns it off. If the charge dropped, it went somewhere.
So a system that has been topped up has a leak by definition — and unless somebody found and repaired it, that leak is still there and still growing.
This is the most common thing we inherit. A building that has been recharged two or three times over a few years, each time restoring operation, each time leaving the cause in place.
What repeated top-ups actually cost you
- 1.You pay for refrigerant again, on a schedule that keeps getting shorter as the leak opens up.
- 2.Refrigerant is released to atmosphere, which carries reporting weight at commercial charge volumes.
- 3.The system runs undercharged between visits — poor oil return, higher operating temperature.
- 4.The compressor absorbs all of it, and that is the most expensive repair on the system.
We will tell you honestly when a top-up is a sensible stopgap to keep tenants comfortable while a proper repair is scheduled. We will not present it as a fix.
Why VRF leaks are harder than split-system leaks
A split system has two connections and a short lineset. A commercial VRF system distributes refrigerant across an entire building.
Large charge volume
Recovering, holding and recharging is a substantial procedure, and the refrigerant itself is a real line item.
Long pipe runs
Distributed through risers, ceiling voids and plant areas, much of it not readily visible.
Many joints and branches
Every connection, branch selector and service valve is a candidate. More units means more of them.
Shared circuit
A leak anywhere affects every zone on that system, so the symptom rarely indicates the location.
The procedure, and the numbers behind it
A leak repair is only finished when it has been proven. These are the steps, including the measurements that separate a repair from an assumption.
- 1
Confirm it is actually a leak
A failed expansion valve, a restriction or a faulty pressure sensor all imitate low charge on gauges. Establishing which you have before touching refrigerant avoids paying for gas you never needed.
- 2
Locate the leak
Systematic isolation and testing across the circuit — joints, brazed connections, branch selectors, service valves, and anywhere exposed to vibration or building movement. On a large system this is genuine diagnostic work, not a quick sniff.
- 3
Recover the remaining charge
Properly recovered, not vented. At commercial charge volumes this matters environmentally and for your records.
- 4
Make the repair
The joint, section or component put right, rather than the symptom masked.
- 5
Purge with nitrogen and pressure test
Lines purged with nitrogen, then pressurised to test pressure and checked at connections. This is where a repair is proven rather than assumed.
- 6
Evacuate to specification
The vacuum pump itself should pull below 50–100 microns. The system is then evacuated to under 500 microns.
- 7
Hold a decay test
Vacuum observed for five minutes. It should read under 800 microns and be holding. The final reading is recorded — that number is your evidence the system is tight.
- 8
Recharge by weight
Total charge weight calculated for the actual lineset, not estimated. The figure is written up near the service valves so the next technician is not guessing.
Ask for the decay reading. A recorded vacuum figure after a five minute hold is the difference between a leak repair that was verified and one that was hoped for. Any contractor doing this properly will have the number and will be happy to give it to you.
Codes that point at refrigerant problems
If your system is showing any of these, refrigerant is worth investigating — though not all of them mean a leak, and that distinction is where money is saved.
Refrigerant records and compliance
California regulates refrigerant handling, and larger commercial systems can carry registration, periodic leak inspection and record-keeping obligations. Commercial VRF charge volumes are often the scale where this becomes relevant.
We log quantities added and recovered as a matter of course, which is what makes the records useful if you are asked for them. Whether your specific system falls in scope depends on its charge and configuration — worth confirming for your building rather than assuming either way, and we will tell you what we find.
Leak detection FAQs
How do you find a refrigerant leak on a commercial VRF system?
Systematically, by isolating and pressure testing sections rather than guessing. Long pipe runs with many joints, branch selectors and service valves mean this is genuine diagnostic work. On a large installation it is a real part of the job rather than a quick check.
Why can't you just top up the refrigerant?
Because refrigerant is not consumed. It is a sealed circuit, so if the level dropped it escaped somewhere, and topping up leaves that leak in place. You end up paying for refrigerant repeatedly on a shortening schedule while the leak itself continues to grow.
How do you prove a VRF leak repair actually worked?
With a vacuum decay test. After evacuating below 500 microns, the vacuum is observed for five minutes and should read under 800 microns and holding. That recorded figure is the evidence the system is genuinely tight rather than assumed to be.
Why is a VRF refrigerant leak so expensive to repair?
Scale. Commercial VRF holds a large charge across long pipe runs with many joints. Locating the leak, recovering the remaining charge, repairing, pressure testing, evacuating and recharging is a substantial job, and the refrigerant volume alone is a real cost.
Can running with low refrigerant damage my VRF system?
Yes. Refrigerant carries oil around the circuit and helps cool the compressor. Running undercharged means poor oil return and elevated operating temperature, which is one of the more reliable routes from a leak repair to a compressor replacement.
How do I know if my system has an unrepaired leak?
The clearest indicator is a history of refrigerant being added. If a contractor has topped your system up more than once, there is a leak that was never found. Capacity gradually declining across a season is the other common sign.
Get the leak found
Certified on Daikin, Mitsubishi and LG — including systems we did not install, and systems somebody else has been topping up.
Next business day commercial service.