I am using Delongy heat pump.
It has a electronic display which shows temperature etc.
But sometime it shows "UF" what is the mean of it,
WHEN IT disply UF, heat pump does not blow hot air.
I checked operators manual came with th eproduct, but could not find the meaning of UF
In electrical terminology UF would mean microfarad or mfd for short. This has to do with capacitance such as in a capacitor which stores voltage to assist motors in starting and running. You have a capacitor attached for each motor, the compressor and the fan motor outside at the heat pump and one on the inside for your blower motor.
Might want to check those or have them checked. I can tell you how to inspect them if you'd like but I'll wait until you come back. It is an easy and inexpensive diy fix.
This would be a first I'd be hearing of a stat telling you that a capacitor is bad, if this is the problem.
Tanks for your reply, This is just indicator such as Auto, Manual , etc.
My manual does not give any key to find this code.
I think it is dedicated to Delongy.
If any one as Delongi heat pump, probably they can tell me what is it.