Daikin Ducted Runs Full Speed In Heat Mode

[bzerk86]

Hello All,

I have recently moved into a new home that has the following Daikin ducted air conditioner set up:

Outdoor Unit: RZQ150HY4A (Super Inverter)
Indoor Unit: FDYQ160KAV1
Controller: BRC1E61

When in heating mode the system seems to behave more like a traditional single speed air conditioner.

When the thermostat calls for heat (even if it's only 1c off set point) the outdoor unit fires up, ramps to a very high speed within a minute or two and will stay there until the thermostat is satisfied. It's at this time the system simply shuts off and the whole process repeats the next time the thermostat calls for heat. It doesn't appear that the outdoor unit modulates down at all, it simply ramps down quickly and turns off.

When in cooling mode the system operates like any other inverter, you can audibly hear the outdoor unit modulate up and down over time.

There are no errors or other anomalies to report.

Cheers,

bzerk

[Brian_UK]

Depending on the model series there was an update to the software to improve performance. Check with your local Daikin agent.

[bzerk86]

A quick update.

Have now had multiple technicians look at the unit and none have been able to diagnose the issue even though they have all witnessed it and say it's not right.

A new symptom is the unit goes into defrost when it's not required. 13c outside, no frost on the coils.

Daikin keep making excuses that the unit is operating this way (inefficiently) due to "oil return" (is this even a big issue for residential systems?) or it's trying to maintain a condensing temperature. One technician form a so called specialist dealer in Adelaide where there "hasn't been a problem I haven't seen or fixed" said that the unit will "learn", well ya know what.... It hasn't in several weeks.

I am really disappointed and frustrated that not even the manufacturer has been able to sort this problem.

Waste of my time and money.

So much for a premium brand with awesome service!

[bzerk86]

Okay,

I have been fortunate enough to have a Daikin tech on site.

Turns out that this particular model of Three phase inverters will only modulate in cooling mode.

The technician called a few other people after witnessing my concern and everything checked out correct and confirmed that this is the designed operation.

While somewhat misleading and inefficient at least I now know that my system isn't going to run itself into the ground and is working as it should.

I have to admit that in the end dealing with Daikin direct was a positive experience, the technician answered all my questions, was thorough and wanted to confirm the operation for his knowledge as well.


Cheers,

bzerk86