Orange leds are common, I have a Vox effects pedal with a valve and an orange led under it.
It has nothing to do with how much power it is using, the heater of a valve works about 6v. Valves can be run without the heater, (cold plate), which is I assume what is done here.
But as every fool knows, a valve that doesn't have an visible orange glow doesn't sound anywhere near as good!