Honneywell Thermostat showing low temp and Frost Mode

[Carra27]

Hi

My thermostat usually shows a room temp of between 18 and 20 degrees

However occasionally it is displaying FROST MODE and showing low temperatures. Basically when it goes like this we can either have heating on or off with no control which is very annoying!

Can anyone advise, I have already looked up about frost mode but I do not know why this mode is happening and cant seem to remove it either.

Many Thanks

 

[EricMark]

When some sensors fail they show zero degrees, in one factory I worked in the guy programming the machine was well aware of this, so wrote the program so if showing zero degrees it would lock out, however not really possible with a domestic thermostat as you may actually get zero degrees.

Most electronic thermostats have one of the standard sensors inside, not really user changed, it is simply a new thermostat job when they go.