Daikin Thermostat Problems?

[tsbrownie]

Howdy,

Got 5 Daikin split types, 4x 22k BTU and 1x 9k BTU. They all go thru periods of the thermostat "sticking" (yep, I know they are electronic). The temp will far undershoot what it's set for (set for 29C and will drop to 24C and I think it would keep going if I let it).

Can't seem to tie it to things like rain, sun shining on the compressor unit or such. Wondering if there's a software bug or some such that's known. Otherwise we really like them.

tsb

[install monkey]

is it going into defrost-quote set at 29c and drops to 24c
why is the setpoint 29 more chance of the compressor overheating

[JoeAT50A]

Howdy,

Wondering if there's a software bug or some such that's known.

tsb
I don't think is bugs.... we wish they could have a sort of setting like off-setting to fine tune.
Typical issues for all brands, return air temperature sensor is detecting non-realistic temperature with +2, +3 Degree C, then your compressor will never cut-off and become over cooling.
Of course location of indoor unit especially for return air sensor location is major issue.
Please ask Daikin specialist to get better counter measurement for this issue.
Mostly happened with Wall Mounted Type and cornor installation.

[Tradewinds]

Any chance they are over sized for the heat load of the room? If the units are too big they could easily run past the setpoint and cause unnecessary cycling. Also check where the sensor is located.

[tsbrownie]

Some good thoughts, thanks. Yes, they are all wall mounted, one is in a corner, the others are not. I wondered if it might be the intake sensor, but it only does it at random. If this were the problem, wouldn't it happen all the time?

Could it be oversized for the space? Good question. We went with the Daikin recommendation for number of square meters. No high ceilings, bay windows or such. Again I think (?) it would do it all the time if they were over/undersized.

Happened again last nite on the master BR unit. Set at 29, actual temp was 23. But it has not done it for months. (Was a hot, humid nite). Our home "office" did it yesterday, set at 29 was 25 actual (was a sunny, hot day). I can't recall it ever doing it before and it's why I left the post. TV room did it last year on and off for a week (can't recall the numbers, but similar).

Daikin service people cleaned the relay on the compressor. Frankly I don't think they believed me. Not something you can video! The lack of predictability makes we wonder if it's bugs (real or software).

[tsbrownie]

Oversized for the heat load. Not sure how I'd find that, but I'm kinda of doubting it since we live in the tropics (Thailand). The office happened in the afternoon when that side of the house is in full sun. The Master BR happened at nite (no moon ;).

I'm wondering if they have a humidity sensor??? The last two days have been swimming pool humid. If the unit is trying to remove moisture, then I could see where it could keep working to try to get it below the 80-90% we're experiencing. Would explain the "random" nature of the problem. The other thought has to do with little lizards parking themselves on the sensors, but I'm saving that as a last ditch guess.