Daikin VRV 3 pipe changing mode

[multisync]

Hi Multisync,

When you say all indoors are on full heat are you 100% sure they were all set to heating only mode (not auto with set point increased). The reason I ask is that this sounds like the unit is continually entering equalization in order to allow a BS box to change mode. I have encountered this a few times usually caused by discharge air from an indoor influencing return air/wall/controller sensor (bad installs).
Possible causes,
Cassette indoor too close to wall (common in small offices) resulting in recirculation of discharge air into return air path.
Unit blowing discharge air onto wall sensor/controller sensor
Ducted units with discharge ducting damaged or missing allowing discharge air to blow into the return of another unit.

This usually results in the indoor unit bs box changing from heating to cooling to heating to cooling…….

Yes you are right about auto full heat. .It's a small hotel installed 2000. Nothing has changed afaik.

The engineer did mention something about him having concerns about one fan coil 'playing up'. Another engineer was on site yesterday working on another system and we phoned and asked him to run one indoor at a time to see if we could find if an individual indoor unit is causing this. He wasn't really involved in this before so we guess a bit unsure of what/why we were trying to achieve, plus he was really tied up trying to get the other system running.

I guess we need to run it on test mode and see or ensure they really are all on heating only ..


Thanks so far and we'll get back on this.