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Community and Q&A

Manual Fan Control With Ducted Minisplit

Clay Whitenack | Posted in Green Products and Materials on

Hey all,

I have a Fujitsu Halcyon ARU12RLFCD installed in the upstairs of our “Pretty Good House”.  I have no complaints, it gets the job done and has plenty of capacity.  I noticed something odd the other day and wondering if it is a bug or just part of the design.

I am unable to alter the fan speed while it is in Heat mode.  When in Cool or Fan mode, I can change the fan speed with no problems, and if I crank the heat way up, the fan will ramp up/down its speed automatically, as expected.  But if I wanted to select the fan speed while in Heat mode, nothing happens.  I have tried leaving it on High for days and nothing happens.

I have two Fujitsu Halcyon ductless heat pumps downstairs, and they do allow you to set the fan speed while on heat.  That makes me wonder if there is either something wrong or if it is just a feature of a ducted unit.

ETA:  I must have something else going on. I put an energy monitor on the unit, and getting some strange readings. It is using 40 watts while off, which is consistent with the mini splits downstairs. But, when I turn it on, the energy drops to 12 watts. Surely that can’t be correct, but I’ve double-checked the monitor and everything seems to be working correctly.

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Replies

  1. Kyle R | | #1

    What remote/thermostat do you have? I have a 12RLFCD with the older style thermostat and can change fan speed while in heating mode.

    There are a ton of weird settings you can change. Maybe reset back to factory settings?

    1. Clay Whitenack | | #2

      I have a UTY-RNNUM. This is our 4th winter with this unit...I am trying to think if I ever remember being able to control the fan speed in the past (in heat mode).

      1. Kyle R | | #3

        That’s the same I have. Can you post a picture of the screen?

        1. Clay Whitenack | | #5

          See attached. Currently set on auto for the fan, but setting the fan setting speed doesn't change anything (when on heat mode).

          1. Kyle R | | #7

            Yeah, looks the same as mine. Maybe check the dip switches to make sure it’s setup for a single controller?

  2. Tobias Meissner | | #4

    I experience the same behavior with our Fujitsu Halcyon ductless unit. I have the UTY-RVNUM thermostat and albeit being able to change the fan speed settings on the thermostat it won't affect the fan speed on the unit at all. Our upstairs unit usually has nothing much to do as our downstairs unit handles most of the heat load -- but would be nice to run the upstairs unit with higher fan speeds to get some air moving.

    1. Clay Whitenack | | #6

      Thanks for the reply. So maybe that is the way it is. Our downstairs unit(s) take(s) care of most of the work as well.

  3. Clay Whitenack | | #8

    I must have something else going on. I put an energy monitor on the unit, and getting some strange readings. It is using 40 watts while off, which is consistent with the mini splits downstairs. But, when I turn it on, the energy drops to 12 watts. Surely that can't be correct, but I've double-checked the monitor and everything seems to be working correctly.

  4. Jonathan Lawrence CZ 4A New Jersey | | #9

    Clay - I have a Fujitsu slim duct and 2 medium static units all set up 1:1. My slim duct was installed with the wired remote you have, but I had a hard time reading the LCD so I swapped it out with a UTY-RVNUM. I am able to adjust the fan speed while in heat mode with this setup. I don't recall for sure, but I believe I was able to do that with the old remote too. The medium static units have a different remote than the slim duct and with one of the units I am able to adjust the fan speed in heat mode, but not with the other. There must be a setting somewhere to allow control of the fan speed.

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