“Indoor unit fan control for energy saving for cooling”
The installation manual for the Fujitsu RLS3 minisplits have this option listed:
“8) Indoor unit fan control for energy saving for cooling Enable or disable the power-saving function by controlling the indoor unit fan rotation when the outdoor unit is stopped during cooling operation.
00: When the outdoor unit is stopped, the indoor unit fan operates continuously following the setting on the remote controller.
01: When the outdoor unit is stopped, the indoor unit fan operates intermittently at a very low speed.”
I’m wondering if anyone can comment on the pros and cons of that? I’m thinking if the fan shuts off it’ll allow moisture to fall off the fins and make it’s way down the drain better, which will remove more moisture from the air in the house. That sounds like a big plus to be, along with the better efficiency that seems like a no brainer to me. Is there a down side to this though? Or could this be another “feature” designed to make minisplits act how users are expecting at the cost of efficiency?
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The downside to intermittent fan operation is the potential for less stable room temperatures, since the room temperature is only sensed by the temperature of the incoming air. Using a wired wall mounted remote and setting it up to sense the temperature at the remote (like a thermostat) solves that issue.
Whether even the intermittent fan function can be disabled when under wired remote/wall thermostat control isn't clear, but maybe. Not operating the fan at all during light loads would use even less power.
Thanks Dana. I think that's worth giving a try and seeing how the room temperatures end up.
I haven't looked at a wall controller for my units mainly because installation would be a pain in the back side.
Fujistu (and others) are now offering RF and Wi-Fi- linked wall remotes, but I haven't dug into the details enough to know if it has the functionality you're looking for. To be sure ANY sensor that's measuring the room temperature will need less seasonal tweaking and have fewer short-cycling issues than sensing the room temperature at the intake air at the head.
If you want to dig into what's available for (and/or compatible with) your mini-split, start here:
https://www.fujitsu-general.com/us/products/split/optionalparts.html
Thank you!
Dana, is there anyway to make an estimate of the savings a wall mounted sensor would give?