Daikin FTY50 GAVAL changes fan speed automatically

[zargar]

Hi guys,

My Daikin FTY50 GAVAL ( i have about 8 units) all change fan speed from max to min, by themselves. To get max fan speed back I need to switch off then back on again and then I have max fan speed for about five mins. After that the AC hums down to min fan speed again. The cooling is still present throughout all of this fiasco.

This only seems to happens during the hottest parts of the day in summer ( i.e. >50 deg. C) and that is when I need the most cooling with the max fan speed. I tested the AC for error codes but there were no errors.

Please help.
Thanks in advance.

[monkey spanners]

Maybe its done to limit the heat taken in by the indoor unit when the outside temperature is high and its difficult for the outside unit to get rid of the heat to the air.

[r.bartlett]

Maybe its done to limit the heat taken in by the indoor unit when the outside temperature is high and its difficult for the outside unit to get rid of the heat to the air.

Daikin only rated to 43 afaik so I am with you on this..

[install monkey]

fty50gaval operating range for outdoor units is 19 to 54 deg

[frank]

Do all of your 8 units have individual controllers or do you have a Centralised controller?

[zargar]

all have individual controllers

[install monkey]

hard wired controllers or infra red ones

[r.bartlett]

Spray water onto one of the condenser radiator for a few minutes if the fan speeds up again then it is as the monkey suggests

[texanul]

Maybe is ice forming on the evaporator and the controller is trying the get rid of ice . Maybe the termistor on the evaporator is bad indicator and keeping the external fan running at low speed. Check the indoor termistor on the exchanger . Take him out from his place and check the operation with him outt from location.