Advice Needed On How Int/ext Fans Work

[nconti]

Hi there. Can someone please explain how my single-split system regulates it's fan speed. in 'auto' mode the fan speed is sometimes on 'low'..even though I have set requested room temperature much lower than actual room temperature.

does this mean that the outside fan is working independantly to lower room temp? why doesn't the int fan go to 'hi' when i lower requested room temp?

if I am not in 'auto' mode but choose a low temperature...will the external fan automatically stop when desired temp is reached? (int fan never actually seems to stop)

apols for low level of understanding but i'm new to this. all help much appreciated.

regards, neil c.

[Brian_UK]

Hi Neil and welcome to the forum.

OUTDOOR FAN: This fan is not controlled directly by you changing the fan speed on the indoor unit. The fan operates when the compressor is running to dissipate the heat removed from inside.

INDOOR FAN: You say that the fan does not speed up when you select a lower temperature. Does it never speed up or does it increase after a few minutes?

A couple of things relating to controls for splits....

The temperature selected or shown on a remote controller should be read as an indicator and not an absolute temperature. You may well set your system for 18° or 16°C but the unit will never achieve that temperature unless it is a cold winter.

There is normally a three minute time delay on most splits before the compressor starts after a demand for cooling occurs. Your fan may stay at low speed until the compressor has started.

What make/model of unit do you have Neil?

[Andy]

Hi there. Can someone please explain how my single-split system regulates it's fan speed. in 'auto' mode the fan speed is sometimes on 'low'..even though I have set requested room temperature much lower than actual room temperature.

does this mean that the outside fan is working independantly to lower room temp? why doesn't the int fan go to 'hi' when i lower requested room temp?

if I am not in 'auto' mode but choose a low temperature...will the external fan automatically stop when desired temp is reached? (int fan never actually seems to stop)

apols for low level of understanding but i'm new to this. all help much appreciated.

regards, neil c.

Hi Neil

Indoor fan is controlled by a probe in the evaporator, changing speed when it senses a tempearture set point below the dew point of the air it changes the fan speed.

The outdoor fan is either controlled on pressure (constant condensing pressure) or by a liquid line probe. The exception to this is some York units that try to reduce the condensing pressure on head pump mode by reducing the outdoor fan speed (this is the evaporator during heating) dropping the fan speed lowers the evaporator load and thus the condensing pressure.

Hope this helps.

Kind Regards Andy

[nconti]

thanx for your quick replies - this forum is great!

i'm going to do the three minute test to see if fan speed changes...

....answers tomorrow.

cheers, n.