Installation mistakes on complex HVAC systems are more common than we’d like to admit. In the world of Daikin VRV (Variable Refrigerant Volume) systems – Daikin’s flagship VRF technology – even small oversights can snowball into major failures, wasted time, and repeated service call-outs. Think of things like miswired controls, poorly installed drain lines, or communication cable errors during install. These issues not only hurt the system’s performance but also chew into your profit margins with return visits and repairs. The commissioning stage is truly your last chance to catch and correct such problems before the system goes live.

At Alpha Technical Training, we’ve seen it all (we’re Daikin’s official VRV training partner in Australia). In this blog, we’ve put together a pre-commissioning survival guide – focusing on three absolutely non-negotiable steps that are often overlooked. Skip these at your peril! They are the kind of pre-power checks that, if missed, can doom your installation and kill your system’s margins. So before you hit that power switch on a new Daikin VRV system, make sure you’ve addressed the following:

1. The Shipping Brackets of Doom

   Yes, those innocuous-looking shipping brackets bolted to the compressors from the factory can wreak havoc if forgotten. Daikin secures each compressor with two sturdy brackets (usually bright yellow) to protect them during transit. You must remove all of these shipping brackets and re-tighten the compressor mount bolts before startup. If you leave them in place, the compressor can’t float on its vibration isolators as designed. The result? Terrible noise and vibration once the system is running. Technicians grimly joke about the “shipping brackets of doom” because failing to remove them can lead to excessive rattling, customer noise complaints, and even potential equipment damage from the undue stress.

   Imagine explaining to a client that the brand-new, premium VRV outdoor unit is making a racket because a couple of brackets were overlooked – not a fun conversation! The cost of that oversight isn’t just a bit of noise; it could mean damaged piping or a fatigued compressor, and certainly a callback that eats into your margin. The fix is simple: always inspect and remove all compressor shipping blocks during installation or commissioning. It’s an easy box to tick on your checklist that can save you a world of trouble.

2. Pressure Testing Protocol: 550 PSI for 24 Hours (No Shortcuts)

   Leak testing the refrigerant piping is one step you cannot rush or skip. After all those flare connections, branch fittings, and lengthy pipe runs in a VRV system, even a tiny refrigerant leak can spell disaster down the line. Daikin’s recommended protocol is crystal clear: pressure-test the field piping with dry nitrogen at ~550 psi (about 3.8 MPa) and hold it for a minimum of 24 hours. In fact, if you’re working on certain smaller-capacity units, the spec might be a bit lower (around 450 psi), but for most VRV systems 550 psi for a full day is the gold standard.

   Why such a high pressure and long duration? Because it’s the best way to reveal any small leaks before you charge the system with expensive refrigerant. A system might hold pressure for an hour and look fine, only to creep down overnight if there’s a pinhole leak. Skipping or shortening the pressure test is practically a guarantee of a future call-back. If the pressure drops during the 24-hour test, you know there’s a leak and you can find it (spray those joints with soapy water, use an electronic leak detector, whatever it takes). It’s a pain to fix leaks, but nowhere near as painful as losing a full charge of refrigerant or burning up a compressor due to low charge later. According to Daikin guidelines, if the pressure holds steady for 24 hours, the system has passed the test – you can then proceed to evacuate and charge with confidence. But if you see any drop, rectify it and re-test until you’re sure. This due diligence directly protects your bottom line: a proper pressure test averts the dreaded scenario of having to return to a finished job because the system leaked out and stopped cooling (costing you labor, materials, and reputation). In short, no shortcuts here – 550 psi, 24 hours – or as we like to say, “pressure test it like you mean it.”

   (And while you’re at it, don’t forget the vacuum step after the pressure test. A triple evacuation to 500 microns is recommended to remove moisture/air– another vital step, though the mistakes around vacuuming are a topic for another day!)

3. The EEV Error: Don’t Power Up the Indoor Units Too Early

   This third mistake is a subtler one and catches many technicians off-guard. EEVs (Electronic Expansion Valves) are used in every indoor unit (fan coil) and any branch selector box on a heat recovery VRV system. Here’s the crucial detail: from the factory, these EEVs are shipped in an open position, but as soon as you apply power to an indoor unit, its EEV will drive closed. If you energize the system’s indoor units before completing your leak testing and vacuum, you’re asking for trouble. A closed expansion valve means you’ve essentially sectioned off that part of the refrigerant circuit. You won’t be able to properly pressure-test or evacuate that isolated section of piping! In other words, powering up the indoor units too early can trap nitrogen, air, or moisture in parts of the system that you think you’re testing, but actually aren’t.

   The correct approach is straightforward: keep the indoor units and any branch selector boxes unpowered until all leak testing and vacuum dehydration is fully done. By leaving the fan coils off, their EEVs stay open and the entire refrigerant network – outdoor unit, all piping, and indoor units – is contiguous for testing. We know the anticipation to fire up the system is high, but hold off just a bit! It can save you from a false vacuum or pressure test. For example, if an EEV accidentally got powered and closed, you might pull a vacuum on the outdoor unit and main lines, get a good 500 micron reading, and think “all good” – while some branch line or coil still has air in it because its valve was shut. Later on, that trapped air and moisture could wreak havoc (corrosion, acid formation in oil, compressor stress). Or a section might have a leak that never saw the 550 psi test pressure. The result? Another avoidable failure and a profit-killing repair visit.

   If you do slip up and energize things in the wrong sequence (hey, it happens), Daikin provides a remedy: you can use a special “Recovery/Evacuation Mode” to drive all EEVs back open for testing. But setting that up and running it is extra time and effort. It’s far better to avoid the EEV error entirely by adhering to the proper commissioning sequence from the start. Bottom line: don’t power up those indoor units until you’re ready to commission the whole system, after leak checks and vacuuming are 100% complete.

Conclusion: Protect Your System and Your Profits

Commissioning is all about sweating the details so that the HVAC system runs flawlessly from day one. The three pre-power checks above – removing compressor shipping brackets, doing a thorough 550 psi nitrogen pressure test for 24 hours, and keeping indoor unit power off until leak/evac tests are done – are simple steps that make a world of difference. They cost a bit of time upfront but can save you massive costs and headaches later. Skipping any of these is like leaving a trapdoor in your installation that you (or your client) will fall through down the road, whether it’s a midnight “no cooling” call due to refrigerant loss, or a costly warranty compressor swap because of vibration damage or contamination.

As the saying goes, an ounce of prevention is worth a pound of cure. Double-check these items on every VRV install before commissioning: it’s your last chance to get it right. At Alpha Technical Training, we emphasize these best practices in every class – after all, we’re proud to be Daikin’s training partner for VRV systems in Australia, and our mission is to help technicians deliver quality installations that stand the test of time. By following this pre-commissioning guide, you’ll not only ensure the longevity of the Daikin VRV system but also protect your own margins by avoiding needless rework.

So next time you’re about to press the “ON” button, run through your mental (or written) checklist: Shipping brackets removed? Check. Held nitrogen at 550 psi overnight? Check. Indoor units still off until vacuum done? Check! Do that, and you can power up with confidence, knowing you’ve set the system up for success and yourself up for a profitable, drama-free job well done.

Happy commissioning – and remember, the best service call is the one you never have to make.