Daikin FDMA100AV1A Heating Issue

Forums › Home Workshop DIY › Daikin FDMA100AV1A Heating Issue

Adama64

5 posts

Wannabe Geek

#320397 9-Aug-2025 10:37

Hi everyone

My Daikin heat pump FDMA100AV1A takes 2 hours to heat an 80 sqm area which includes 2 living rooms from 17 degrees to a set temperature of 22 degrees Celsius. Please see indoor stats below.Any help will be appreciated.

Start 4.00 Am room 17. First cycle

4.08 AM = TH2,3 36 TH 5,6 17

4.09 AM = TH2,3 38 TH 5,6 18

4.10 AM = TH2,3 40 TH 5,6 18

4.08 AM = TH2,3 36 TH 5,6 17

4.11 AM = TH2,3 42 TH 5,6 18

4.15 AM = TH2,3 44 TH 5,6 19

4.18 AM = TH2,3 45 TH 5,6 20

4.28 AM = TH2,3 43 TH 5,6 21

4.41 AM = TH2,3 44 TH 5,6 21

5.09 AM = TH2,3 39 TH 5,6 22

5.16 AM = TH2,3 38 TH 5,6 22

5.54 AM = TH2,3 38 TH 5,6 22. Still blowing no cycle cut

6.01 cut out stop blowing

6.10 AM = TH2,3 36 TH 5,6 21 second cycle

my installer says its normal

lxsw20

3559 posts

Uber Geek

Subscriber

#3401216 9-Aug-2025 11:30

With out any specifics of the space you're trying to heat no one can offer much help.

HowickDota

424 posts

Ultimate Geek

#3401217 9-Aug-2025 11:31

Seems like it got to 22 after 1 hour though which is not unreasonable I think.

Depends as well if that thermistor is measuring return or controller temp, return would be slightly warmer given it's higher.

The output seems normal but hard to say without knowing the supply airflow, 11kw at a 22c delta would require 416l/s.

It is probably not running at full output the whole time too and slows down capacity/fan speed once it reaches closer to setpoint.

tweake

2408 posts

Uber Geek

#3401237 9-Aug-2025 13:05

basically its gone from 17c to 20c in 10 minutes. then from 20c to 22c in roughly an hour.

thats how they are meant to operate. typically they run full noise up to a few degrees before the target temp, then it slows down more and more as it creeps up to target temp.

without knowing house location (outside temps) and insulation level its hard to say, but it sounds like its actually oversized.

the other factor here is your only dealing with air temps, not house temps. the mass of the house sucks the heat out out of the air and it generally takes many many hours to heat the house. you don't really get comfort until the mass of the house is heated up and the house radiates that heat back to you. a simple test is to turn the heatpump off and if it goes cold rather quickly then the house is not been properly heated. this is a really common issue with kiwis home heating.

fe31nz

1235 posts

Uber Geek

#3401358 9-Aug-2025 23:05

If there is an option to manually set the fan speed, set it to maximum and see what happens. Or if there is a special "powerful" mode or something like that. Either of those settings on some heat pumps will make it work at full power until it reaches the setpoint, so it will actually go over the setpoint somewhat. On normal settings, heat pumps will usually slow down so that they reach the setpoint without going over it, but then they can take much longer to get there.

And, of course, the temperature you set as the setpoint will not usually match the actual room temperature. The heat pump normally measures the temperature at its air intake, which is high up in the room and hence is normally hotter than lower down where the humans actually live (hot air rises). To compensate for that, they normally adjust the value arbitrarily, so if the setpoint temperature is 22 C, the heat pump may be adding say 2 C to that for its expected intake temperature for that setpoint temperature. These preset compensation factors will usually not match what actually happens with your particular installation and the airflow in your particular room. For example, in out kitchen, to get an actual 22 C on a thermometer we have at shoulder height out of the airflow behind a bookcase, we need to set the setpoint temperature to 20 C on a cold day and to 19 C on a warmer day. Some recent heat pumps now have a hidden away option to adjust the compensation factor. You may need the maintenance manual to find such options, so try looking for a downloadable version of that.

Adama64

5 posts

Wannabe Geek

#3401379 10-Aug-2025 09:18

Outdoor RZAV100CV1

Indoor FDMA100AV1A

Controller BRC1E63

got 2x350 return and 2x350 supply 1 350 with y 2/200 6 mt to diffuser and 2nd 350 with 250and200 y both 5mt to diffuser

this all goes to ground floor upper lever for bedrooms with multi split

tweake

2408 posts

Uber Geek

#3401395 10-Aug-2025 11:40

fe31nz:

If there is an option to manually set the fan speed, set it to maximum and see what happens. Or if there is a special "powerful" mode or something like that. Either of those settings on some heat pumps will make it work at full power until it reaches the setpoint, so it will actually go over the setpoint somewhat. On normal settings, heat pumps will usually slow down so that they reach the setpoint without going over it, but then they can take much longer to get there.

the problem with that, is efficiency. most people can't really tell the difference of a few degrees and by slowing down it makes it far more efficient. power mode will take the AIR temps to setpoint quickly, but it costs more for no/little comfort gain.

a lot of the wall controllers have the temp sensor built into them, just need to make sure the system is set to use it. also that the controller is installed at the correct height as per the manual.

Adama64

5 posts

Wannabe Geek

#3401450 10-Aug-2025 12:32

The thermostat is set on controller not return

Quic Broadband

Move to New Zealand's best fibre broadband service (affiliate link). Free setup code: R587125ERQ6VE. Note that to use Quic Broadband you must be comfortable with configuring your own router.

Adama64

5 posts

Wannabe Geek

#3401451 10-Aug-2025 12:34

Thermostat is set on controller not return and 1.5 mt high

tweake

2408 posts

Uber Geek

#3401463 10-Aug-2025 13:22

Adama64:

Hi everyone

so whats the problem you would like help with? the data suggests its working as it should.

it would also be helpful to know what area of the country your in and what level of insulation the house has, or at least some details of age, types of windows etc. so we can work out if its sized correctly.