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New Daikin ductless - LOUD oil pumping noise

Just had a new Daikin ductless unit installed with 4 heads, and the oil pumping noise coming from the outside condenser is VERY loud. Picture a large boiling cauldron, blub, blub, blub, every 10 minutes or so. This is not a noise related to the defrost cycle and so far has only happened when heating. We have one main 18k in the living room/kitchen and one 7k in each bedroom. It's also not the typical gurgling noise that one would expect if there was air in the lines. It's also loudest when using the main 18k unit, and becomes quieter when using additional heads.

The technicians have been out several times, admitted it's louder than expected, tested the system, and claimed all is well. They said they even called Daikin who didn't have an answer either as to why it's so loud, and they both even said they always mount these nears buildings, on walls, etc.,without issue. To them it's currently a mystery as to why the system is so loud with our specific installation. They even tried using rubber dampeners to pull the lines away from the wall, which didn't help. When next to the condenser, you can hear the noise reverberating from where the lines exit the unit.

Their solution is to move the system to the other side of our house, away from all bedrooms, at a cost of $1600 to me. They said it was unforeseen, so they are not responsible otherwise, and even mentioned this is "at cost" for them. As of now, the loud pumping noise is unacceptable to us, and is something I've never even been able to find as a problem listed anywhere online. No other issues with the system after 6 months, but this noise has gotta go..please help!

Condenser - 4mxs36RMVJUA
1 - 18k FTXS18LVJU LV head (line length 70')
3 - 7k FTXS07LVJU7k heads (line lengths are 10-40 ft)


    EBEBRATT-Ed Member Posts: 13,443
    The first thing to do is take the charge out of the unit and evacuate and recharge it with new refrigerant. And maybe remove the compressor and recharge the oil as well

    I doubt that anyone that knows anything would move a unit that exhibits symptoms like that without trying to recharge it first and also check the piping for leaks or obstructions
  • AnnoyingDuctless
    AnnoyingDuctless Member Posts: 5
    Agreed. However, they came out on two different occasions, didn't find any leaks or obstructions, and said since everything else passed inspection their next step was to move it. Obviously I can't tell them how to do their job, i.e. force them to evacuate and recharge it, but any advice is appreciated on next steps and negotiating..since it seems buyer beware at this point..
    EBEBRATT-Ed Member Posts: 13,443

    And if they move it and the problem continues?
  • AnnoyingDuctless
    AnnoyingDuctless Member Posts: 5
    Since they haven't found any other issue with the system, in their mind the problem would be solved because it's then far enough away from any rooms to cause noise disturbance.
  • wesPA
    wesPA Member Posts: 34
    Besides the noise, how does the system perform? I would double check that all the wiring/piping is terminated properly. You could run each zone individually and make sure refrigerant is being routed to the proper indoor head. I had one situation where wiring was crossed on two indoor heads and it went unnoticed for 3 years!
    I've installed quite a few of the exact system you have, and the noise you are describing is not normal. Your line lengths seem sufficient; If you had a single zone with an 8' lineset then that would be different.
    Was a proper evacuation and start up done of the system? Were the noises noticed right away?

  • ayetchvacker
    ayetchvacker Member Posts: 57
    If I were in your shoes I would request that a manufacturer field rep pay a visit to have a look. What you’re experiencing is definitely not normal and probably not good left alone. Something is up. It would be difficult to pin down exactly what from my recliner which is why I suggest you get a field rep out. Either the installers made a mistake they don’t see or don’t want to address or the machine has and issue or is not set up correctly. Now is when you find out how good the company you hired really is. Good luck
    Fixer of things 
    Lead Service Technician
    ‘09Moto Guzzi V7
  • pecmsg
    pecmsg Member Posts: 3,885
    I've had to install larger vibration eliminators

    on a few jobs.
  • TAG
    TAG Member Posts: 751
    Does it make the noise when all are the heads are running ... ? What kind of a wall?

    I notice the most noise from our brick wall mounted 3 head Mitsubishi system -- when they are not all calling and running. When the unit is ramping up and down and having to modulate

    They all make some noise when not running as some of the refrigerant has to always flow to all the units -- assume you have direct connections to the outside unit and not branch boxes.

    They do gurgle when they are low .... one of mine years ago made that noise. Is the system working correctly otherwise? Good heat from all the heads at once ?

  • clammy
    clammy Member Posts: 2,912
    Personally any mini split installed on a wall mount is to masonry only and usually only on commercial jobs due to transmission of noise and vibration . On all residential mini split I use there floor base and sit it on concrete lentils this eliminates any noise ,makes easier to clean and service . Of course it cost a little bit more but eliminates noise transmission and eliminates any chance of vibration . It only took one job to make me switch . In some cases you have no choice but when faced w that you look at where bedrooms are located and do a little thinking plus you also ensure that you line set are with in the mini lengths . I usually inform the customer that they are a little noise in heat mode over ac due to the reversing valve . Usually this is not a issue personally I would get in touch w the local rep and make sure this is acceptable because as time goes on the installer is less likely to deal w it . It’s always better to strike while the iron is hot
    Peace and best of luck clammy
    R.A. Calmbacher L.L.C. HVAC
    NJ Master HVAC Lic.
    Mahwah, NJ
    Specializing in steam and hydronic heating
  • AnnoyingDuctless
    AnnoyingDuctless Member Posts: 5
    edited March 2022
    Here's a picture of the setup outside, the wall is T-111 siding with drywall. The heads push heat just fine when all running together and the sound decreases as more heads are engaged. However, it's the worst when running just the 17k Unit, which of course is the one we use almost exclusively. The line cover just acts like an echo chamber, glug glug glug, I'm in the Northwest and it's loudest when it's below 45 at night. They did install 1/2" rubber dampeners under the wall cover, but it didn't help.

    The noise also wasn't noticed by us right away, I assume because the system was installed when the weather was mild, and the bedroom next to the condenser is a guest room, so we weren't spending much time in there. The first night I tried to sleep in there I knew something was off.

    Lastly, this noise doesn't come out of the head units. They're all pretty silent and make typical fluid circulating noises as one would expect. This comes through the wall, pretty much as soon as the lines touch the house. I can hear it starting from the floor and follow it up to the head unit.

    Thanks for all of comments and feedback, seems my next step is to reach out to the Daikin Rep.

  • jad3675
    jad3675 Member Posts: 127
    I wonder if the lineset is a bit too packed into the cover? It might be worth it to remove the lineset cover (and any fasteners holding down the linesets inside the cover) and let the linesets move around a bit when the unit is running. If that addresses the issue you could run a separate lineset cover for a head unit. Might look a bit off though.
    EBEBRATT-Ed Member Posts: 13,443
    edited March 2022

    Again, if charged right and no restrictions you shouldn't be hearing and "fluid circulating noises" Looks like they did a nice install. I would still have it evacuated and recharged
  • Harvey Ramer
    Harvey Ramer Member Posts: 2,225
    Does your installation meet these specs? 
    A good test would be to flip it into AC mode. See if the problem goes away. If it does, it's likely low in refrigerant or incorrect piping. If it's low in refrigerant the unit can't generate the velocity needed to return oil to the compressor. 
  • AnnoyingDuctless
    AnnoyingDuctless Member Posts: 5
    edited March 2022
    @Harvey Ramer Would the temperature affect this? The noise I'm experiencing is occurring mostly when below 40. So far I haven't noticed it with A/C but will confirm this evening, and yes, it's within those specs. Interestingly enough, it will be out of those specs if the they move it as they have proposed.

    I've contacted Daikin and requested a site visit by a rep, but was told I need to go through the installers who provided the unit.