VRV indoor units

[r.bartlett]

Chaps

we have got a system with 16 indoor units and an itouch. The Itouch is set all to heat 23 but 3 of the indoor units keep changing over to cool mode after 10 minutes or so

The rooms are unoccupied so we know no one is changing them over at the local controller

also the VAMs have been set to low but keep switching over to hi

Is there a setting I am missing here?

[AbsoluteWDJ]

1. The units that switch to cooling, check DS1-1 isn't set to ON - BS BOXES. This is a cool/heat changeover switch.
2. The VAM units, wire a controller to P1-P2, set 17-7-02 field setting for ventilation mode on Itouch control. Then, go back to Itouch control point registration and enable ventilation mode on the group address for the VAM unit.


Hopefully this will resolve your issues.


Regards

[VRVIII]

Have you checked to see if the I touch has been configured with heat/cool change over groups?

[brunstar]

yeah put them in change over groups. You may also find that the reason they are changing over is that the other fan coils are close to the return air sensor of the other units and the fan coils that are changing over may be getting a gut full of hot air which is giving those fan coils an incorrect return air reading and allowing them to short cycle.