new Daikin: 1 of 4 units doesn't heat

[AustrianinParis]

We just moved into a new apartment with a Daikin aircon/heating system (FVXS25FV1B), with 4 indoor units and one outdoor.

Since winter came early this year in Paris I already started the heating, i.e. I tried to. One of the four units just does not heat. It has the same settings as the three others, and when I start it it correctly opens its flap but then: nothing. Apart from a very very soft cool breeze.

Not even when I choose 30° Celsius and strong ventilation. It has the same settings as the three others.

There is no timer set, and the other modes (just ventilation, cooling) seem to work fine. (Didn't want to test the cooling too extensively …)

I also ran the test with the error codes but it said that everything is okay.

I would have suspected that something's wrong with the heating thingy but since the fan doesn't work in heating mode too I ruled that out.

This is a new system and I know that I could just tell our landlord to call a service guy. But since this is my first air-con I wanted to check beforehand if there maybe is some little silly mistake I've made. (Plus the landlord is not the easiest to reach.)

Any ideas? Thanks so much!

[paul_h]

Sounds like you will need to get someone out, could be faulty TX or even the service valves shut.

[AustrianinParis]

Thanks for the quick reply! (By the way: what ist TX?) But something new just happened. I turned the unit on (which I've been doing a few times today just to be sure) and – it worked!

For exactly one minute. In which it definitely hadn't brought the room to 26°C. After that: soft cool breeze again.

Turned it off. Turned it on again a few minutes later. Same outcome. That doesn't change the verdict that I have to get our landlord to call the company, right?

[paul_h]

TX is valve that lets refrigerant into the system. If refrigerant can't flow, the unit can't get warm and the fan won't blow warm air.
It sounds like a problem with the unit or install, so if you are a novice to refrigeration, it's better to contact you landlord.
As you say, you get the other three units working, so it doesn't seem like it's something you are doing wrong.

[multisync]

Turn off the other 3 and try it in heating and cooling. If it works correctly then it is possibly a refrigerant problem.The indoor fan will only run properly when the indoor coil reaches a certain temperature -that explains todays running... If it doesn't work then it is a fault on the system. If it is the wrong mode it will just shut the unit off and the green light will flash.

Multisync
london

[SkyWalker]

yes thats what i was going to suggest, only run the unit on its own with the other 3 off, the indoor coil has to "pre heat" to somewhere around 35C before the indoor fan motor will start, this is to stop nuisance calls from people thinking that there unit is blowing cold/ambient air in heating.

if the one unit works fine on its own then i would say the refrigerant charge would need weighing out. this would require an engineer with a safe handling cert so you would need to call someone anyway.

[AustrianinParis]

Thanks, you all! I've tested it with another unit turned on and with the unit in question being the only one. No big difference.

Started it once again right now (after having turned off another unit 10 min. ago) and again the fan started (after the usual waiting period) and kept blowing for less than a minute. But the air that came out was not really warm (I chose 27°C to be sure). Not icy, but definitely not what you would call "heating".

I'm writing our landlord as we speak …

[AustrianinParis]

Update: Fan has been running for over 3 minutes now! (Yay!) But still no heating. I'd say something like 19-20°C instead of 27°. Never mind …

[frank]

I've got a feeling that the indoor coil sensor is dislodged.

Does this fan coil operate correctly in cooling mode?