We installed three brand new Daikin units at Reflections at Keppel Bay recently. Standard job, standard handover, everything running the way it should.
A few days later the customer called. There was a sound coming from the units. A hissing sound.
That is a call you take seriously. Hissing from an aircon usually means one thing, and it is not a good thing.
Standing in the room hearing nothing
I went down to the unit. We switched on all three, and I stood there waiting for it.
Nothing.
I went room to room. Master bedroom, second room, third room, back to the master. Still nothing. The customer was standing there watching me walk in circles and I could feel the conversation heading towards “are you sure you believe me”.
Then, out of nowhere, it started. Master bedroom.
And I could not place it.
It was not vibration. Vibration you feel through the bracket and it changes when you touch the casing. It was not water, because drainage gurgling has a rhythm to it and it comes from the drain side. It was not the sound of refrigerant moving through an expansion valve either, which is a short hiss right after start up and then it settles.
This one just sat there. Steady, dry, electrical. Nothing I had heard in years of doing this.
I will be honest, I stood there for a while thinking what on earth is this.
Then I looked at the front of the indoor unit and saw a small logo I had walked past three times already.
Streamer.
What Streamer actually is
Streamer is Daikin’s air cleaning technology, and it is built into the current iSmileEco+ series sold here in Singapore. If you bought a new Daikin recently, there is a good chance you have it.
It is not a filter. It is a plasma discharge. The unit generates a stream of high speed electrons inside itself, and those electrons break down odours, bacteria, allergens and viruses at a molecular level as air passes through.
It is genuinely clever technology. It is also, unavoidably, an electrical discharge happening inside a box on your bedroom wall. And electrical discharges make a sound.
Daikin documents this openly. In the operation manual for the series it says plainly that the streamer discharge may generate a fizzing sound and that this does not indicate a defect. Daikin’s global troubleshooting pages describe the same thing as a hissing sound, and note it can change to a crackling or buzzing tone depending on conditions.
So the sound is not a fault. It is the feature working.
Why it starts on its own, which is the part that catches people
Here is the bit that had me walking in circles, and the reason this one is so easy to misdiagnose.
The Streamer does not necessarily run the whole time your aircon is running. It runs on the unit’s own logic. There are two ways it comes on:
Flash Streamer air cleaning. This is the air cleaning function itself, and it is on by default from the factory. When it is running, an indicator LED lights up on the indoor unit.
Mold Proof operation. This is the sneaky one. When Mold Proof is set to automatic, the unit runs a drying cycle after your cooling or dry operation stops, and it runs the streamer during that cycle to keep mould and smells from developing inside the unit. So the aircon can be sitting there apparently idle, and then start hissing by itself.
That is why nothing happened while I was standing in the room waiting for it, and why it fired up later without anybody touching anything. The unit was on its own schedule, not mine.
If you have ever been told “it only does it sometimes, usually at night” and gone down and found nothing, this is very likely what you were chasing.
How to turn it off
First thing worth knowing, and it surprises most people: Streamer is switched on by default. Nobody enabled it. Your unit left the factory that way. That is exactly why a brand new aircon starts making a noise the owner has never heard before and assumes something has gone wrong.
The second thing is why it is so hard to find. On the iSmileEco+ remote there is no dedicated Streamer button. The setting is buried inside a menu, at item number three. You are not going to stumble across it by pressing things.
Method 1: through the remote controller
These are the steps for the CTKM ZVMG and FTKM ZVMG series, which is the current iSmileEco+ range:
- Hold the MENU button for about 2 seconds
- Use the SELECT up and down buttons to scroll to item number 3
- Press MENU. You will see “on” blinking on the display
- Use the SELECT up and down buttons to change it to off
- Press MENU to confirm
- Press CANCEL to return to the normal remote display
Your confirmation that it worked is on the unit itself, not the remote. The indicator LED on the indoor unit lights up when the Streamer is running and goes off when it is not.
To turn it back on later, repeat the same steps to item three. This time you will see “off” blinking, change it to “on”, press MENU to confirm, then CANCEL to exit.
Daikin Singapore has published a short walkthrough of this on their own channel if you would rather watch it than read it: How to enable and disable Streamer function for CTKM ZVMG and FTKM ZVMG series.
Method 2: through the app, which is much easier
If your units are connected to your wifi and set up in the Daikin Mobile Controller app, forget the menu entirely.
Open the unit in the app and there is a Streamer control right there on the screen, with a simple on and off toggle. One tap. You can do it per unit, so you can switch it off in the bedroom from your bed and leave the living room running.
Honestly, if you are going to be adjusting this at all, connect the app. Six presses on a remote at item three of a hidden menu versus one tap on your phone is not a close contest.
Do not forget Mold Proof is separate
This is the part that catches people out, so it is worth repeating. Streamer and Mold Proof are two different settings.
Mold Proof runs a drying cycle after your cooling stops, and it runs the streamer during that cycle. So you can switch the Streamer air cleaning off, sit down happy, and then hear the same sound again later when the unit starts drying itself out. At that point most people conclude the unit really is faulty after all.
If the sound comes back after the aircon has been switched off, Mold Proof is the one you still need to deal with. It has its own setting in the same menu system.
It took me a few minutes with the manual to work all this out standing in the customer’s bedroom. When I finally cancelled it and the room went quiet, he actually jumped and shouted yes. That is not a reaction you get every day for changing a menu setting.
Should you turn it off?
Here is where we have to be straight with you, because switching it off is not free.
Streamer is doing something real. Mold Proof in particular matters in Singapore. Our humidity is brutal on aircon interiors, and a unit that dries itself out after every cycle is a unit that grows less mould and smells better for longer. Turning that off to gain silence means you are trading away part of what you paid for.
So our honest position is this. Do not switch it off across the whole house by reflex. Switch it off where the noise genuinely bothers you, and leave it running everywhere else.
That is exactly what our customer chose. We explained the tradeoff, he switched it off in the master bedroom where he sleeps, and left it running in the other two rooms. Sensible answer. Quiet where it matters, air cleaning where it costs him nothing.
If you do turn Mold Proof off permanently, just be a bit more diligent about servicing, because you have removed one of the things that was protecting the inside of the unit for you.
When a hissing sound is NOT the Streamer
Now the important part, because we do not want anybody reading this and ignoring a real problem.
Streamer is a steady, dry, electrical sound that comes from the indoor unit itself and stops the moment you cancel the function. If you cancel it and the sound stops, that was Streamer. Case closed.
Treat it as something else if:
- Your unit is not a Daikin, or is an older Daikin with no Streamer logo on the front
- The sound continues after you have cancelled both Streamer and Mold Proof
- The hissing comes with weak cooling, ice forming on the pipes, or a sharp chemical smell
- The sound is coming from the pipework or the outdoor unit rather than from inside the indoor unit
- The unit is cooling noticeably worse than it did a month ago
Those point towards refrigerant, and refrigerant problems do not fix themselves. A system low on gas will keep running, keep drawing power and keep failing to cool, and the compressor is the part that eventually pays for it. If that is what you are hearing, get aircon repair in Singapore done properly rather than waiting it out. If a leak is confirmed, the honest fix is finding and sealing it, not just an aircon gas top up that buys you a few months.
Why we bothered writing this up
Because almost nobody knows about it yet.
This technology is new to the Singapore residential market, the units are only now going into homes in volume, and the sound it makes is close enough to a refrigerant leak that it worries people. We could not find a straight explanation of it anywhere in local search, which is usually a sign that plenty of people are about to go looking for one.
There is also a less comfortable version of this story. A customer hears hissing, calls someone who does not know what a Streamer is, and gets quoted for a gas top up on a unit that was installed three weeks ago and is perfectly fine. Nobody has to be dishonest for that to happen. They just have to not know.
So now it is written down.
If you have a new Daikin doing something you cannot explain, or you want an aircon installation in Singapore handled by people who will actually come back and figure it out, WhatsApp us at +65 8818 5781. Free site survey, and we will tell you straight whether you have a problem or a feature.
