Fujitsu Heating Problem

[Ausfrigy]

Hi all, My Fujitsu Ceiling Cassette AUT25RZAL keeps cycling off just when we need heat, if left on it eventually heats the room but is a damn nuisance. Shouldnt it keep heating untill it reaches cutoff temp of thermostat? thanks in anticipation

[nike123]

What is outdoor temperature? Is it clean?
If yes, put your gauges on it (when in cooling mode) and check pressure when on heating. Pay atention if pressure fall significantly when indoor unit fan start and rise again when cold air blowing prevention stops fan again. If yes, you are short of gas or you have restriction.
Then recover gas and weigh it to establish if it is short of gas or restriction.

[cadillackid]

sounds exactly like Short charge to me.. those units will turn indoor fan on only if pipe temps are warm (88 degrees f i believe).. if the pipe temp drops below that the unit will kill the indoor fan till pipe temps warm up again...

if it is short of gas you also might notice on cold days the outdoor coil freezes over very unevenly indicating early evaporation in the outdoor coil...
-Christopher

[bigor_2]

in cooling mode is OK?
in heating mode outdoor fan is max-speed?
in heating mode compressor is starting?

[John MacK]

Is there no fault code showing in the controller?

I'm going to a similar problem soon.