Noisy Daikin heat pump…Help required please

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Perkynana

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#320433 14-Aug-2025 08:06

We have a Daikin multi split system…1 outdoor unit and 2 indoor heads. Been in the house about 7 years. It works well heating the house but lately it become quite noisy…mainly at start up in morning and after shutting down in evening.

The inside heads make what I would describe as light ticking, cracking or popping sounds. This starts about 2-5 minutes after shutting down in evening and can last maybe 30-40 minutes before stopping. Occasionally it will make a pop sound at a random time like 3am or in the middle of the night….this is a problem as one of the heads is in a bedroom and wakes me up.

On start up the head unit cracks or pops etc for a few minutes then system just settles down and performs normally without making these noises. I can hear a bit of gurgling type noise at start up but that goes quickly and I understand this is normal.

The smaller bedroom unit is the problem as it needs to be a quiet space. This smaller unit also gets most use…probably get used twice as much as big unit.
Im not very technical or mechanically minded…just an average home owner that wants things to work properly so feel free to start your replies with ..you muppet…lol

Does anyone know what is causes this problem? It sound like it comes from the right hand side of unit….maybe that black box structure you see when you pull up the front panel to access filters.

Do I need a Daikin service agent or electrician to come and inspect?

Im central Auckland so if anyone can recommend a good company to contact I’m all ears.

Thanks in advance for any help.

Further info.

outside unit model 4 MXM68RVMA

indoor unit bedroom CTXM25RVMA

longe unit CTXM50RVMA

House is small 110sqm 2 story 2 bedroom townhouse. Outdoor unit in courtyard pretty much back to back to indoor bedroom unit.

lounge unit about 3-4 metre pipe run from outdoor unit.

We are Auckland. Unit only get used for heating 3-4 months each year. Normal day would On at 6am off at 9am or longer on a cloudy or cold day.On again at 4pm until 10ish. We never use for cooling as bedrooms downstairs are cool due to sun path and location. House has really good cross flow ventilation. Never really run the units overnight as not required

House get really good morning sun, has ok ish insulation. The lounge is kitchen and dining open plan with high skill ion roof…hence the slightly bigger unit in that space.

timmmay

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#3402507 14-Aug-2025 10:04

My best guess is this is the plastic and metals expanding and contracting, and the noises of everything moving around as it happens. You may be able to reduce the noise when it's turning off by putting it onto fan mode for 5 minutes before you turn it off. I doubt there's much you can do about the noise when it turns on if it it what I think it is.

johno1234

2838 posts

Uber Geek

#3402510 14-Aug-2025 10:29

Has it been serviced/cleaned/filters cleaned regularly? If it has built up a lot of dust and fuzz it might be getting hot.

Perkynana

27 posts

Geek

#3402518 14-Aug-2025 10:46

Thanks…will try the fan mode idea…haven’t tried that.

One thing I noticed I when I got up on chair to try and find source of cracking sound…I opened up the big front flap to look inside and the noise stopped.

So this morning as soon as I turned off heat pump I immediately opened the big front flap….got no popping or clicking sound.

So not sure if that is part of the issue. Does anybody know if you open that flap does it cut power to unit like a safety?

Yes Johno , filters cleaned regularly every couple of months by me..just light vacuum. Unit has never had a professional clean or service but the installer came and removed and reinstalled the bedroom unit about 6 months ago as we renovated that room and put insulation and new gib on wall.

I might give whole unit a bit of a blow/ vacuum.

Is it worth getting a professional service do you think?

I read a bit online about clicking , cracking and poping noises…so it seems I am not alone.

I notice the Daikin plastic casing on my model is pretty lightweight and flexes when you push it so could be that as well. Doesn’t make sense for the odd random pop we get at 3am which is 6 or so hours after unit is turned off.

I never had a multi- split unit before but I don’t think they are a good idea for a bedroom….you can definitely hear the two indoor heads “talking to each” when you start up them independently or together. I think a simple back to back single would work best in bedroom where quietness is important.

With my multi split the units seem to toggle on and off which creates extra noise.

Just something for others to consider. I actually was set up originally just to go two heads and two motors but installer thought multi split would be lower cost to run so we went that route.

cheers

timmmay

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#3402528 14-Aug-2025 10:54

The clicking / popping is probably the parts moving relative to each other and rubbing, opening the cover may reduce it. I don't think it can be eliminated. You could try earplugs.

A professional clean is a wet clean, it gets dust, viruses and bacteria that have built up between the fins out. It's worth doing every couple of years. I usually do it myself.

Perkynana

27 posts

Geek

#3402736 15-Aug-2025 08:55

Timmmay…you’re a legend.

Tried your suggestion…ran fan mode just before shutting down…that fixed it. Will try again tonight.

I gotta say the way my brain works I’d never think to need to cool the heat pump system before turning off.

Its a bit like telling someone to put some heat beads or charcoal in oven to get it up to heat quicker or after your driven from Auckland to wgtn in your car to immediately open your bonnet and throw some water on the engine to cool it…lol.

Maybe if the manufacturers made their equipment better quality..the human wouldn’t need to get involved with a fix. I mean you can google and find this clicking popping issue across a range of brands.

I can see on my Daikin that the main indoor plastic casing around unit is lightweight and slightly warped from the heating. It flexes when you touch it.I mean these things are meant to run for a long period of time and at a moderate temp 18-21c to provide heat to a space. It’s got sensors up the wazoo…why doesn’t it use its own intelligent eye to work out if it’s internal organs have a got a bit hot and switch to cool itself down at close.

Ok so now we just got the clicking on start up to solve…you seemed to have an idea on that..Care to share your thoughts.

Thanks again