I have been trying to figure out my highrise rental unit's oven timer functions for years. I don't have a model for it, but based on this post, it looks like an Admiral. Here are medium-range and close-up shots of the controls:
I was able to figure out how the countdown timer works (orange needle on the left most dial), but based on the lit LED above the Temperature dial, it doesn't actually turn the oven off once it starts to buzz, even though I have the "Selector" dial on "TIME BAKE" (right side dial). Neither does the LED turn off when I silence the buzzing by turning orange needle to the off position (presumably, the symbol just under the 12-o'clock symbol).
One set of instructions that seem to apply to my dials is a generic set of GE instructions (see ANNEX below). However, it doesn't really describe what one can expect of the countdown timer. It only describes how to specify the bake time using Start and Stop dials.
Regarding the Start and Stop dials, I do indeed see the Start and Stop buttons pop out when the clock reaches the times on their dials. However, LED doesn't turn off before the Start time is reached or after the Stop time is reached. Again, this is with the Selector dialed to "TIME BAKE".
I don't actually see the heating elements glowing when the LED is on, but since I don't know much about ovens, it seems possible to me that they might still be turned on at a low level. I admit that this would be counterintuitive, as temperature seems to be regulated by cycling the hearing elements fully on and off rather than operating them at a some intermediate power level.
Along the vein of temperature control, I noticed the ANNEX mentions that it is not possible to time bake and temperature cook at the same time. However, I think I saw the LED cycle off and on within the duration between Start and Stop times. So I'm wondering if that limitation is very model specific.
Regarding the trustworthiness of the LED, I noticed that it hasn't turned off for a long time since the Stop time. Are those older ovens known for using the LED to indicate things other than the activation of the heating element? That would entirely change my speculations on the oven behaviour in response to countdown timer and Start/Stop knobs. (Subjectively, the oven does seem to have cooled down a bit in the time it took me to assemble this post, even though LED remained on for the whole time).
Can I conclude that the timer is audio only, and doesn't affect the oven operation?
Does the LED actually mean that heating elements are on? I find it hard to tell, as the oven takes so long to heat up and cool down.
If the answer to #2 is "yes", then why is the LED on before the Start time is reached, and after the Stop time is reached?
Have older ovens been known for using the LED to indicate things other than the activation of the heating element?
Extract from "Range - Timed Bake and Delayed Bake Options" Copyright 2018 GE Appliances, a Haier company http://products.geappliances.com/appliance/gea-support-search-content?contentId=18672
To set the automatic oven timer, use the two dials next to the clock, marked "Stop" and "Start". Each dial is marked off in 15 minute segments and numbered by the hour. The pointers on these dials can be moved only when the knob is pushed in. (There is a sound when the pointers are turned.)
Note: Before setting these dials, make sure that the range clock is set to the correct time of day.
To set the oven to come on at a later time:
Push in and turn the STOP pointer to the time of day the oven is to stop.
Push in and turn the START pointer to the time of day the oven is to start.
Turn the oven SET knob to "Time Bake".
Set desired oven temperature.
When the range clock advances to the time of day that was selected for "Start", the START knob will pop out and the oven will begin heating. When the "Stop" time is reached, the STOP knob will pop out and the oven will turn off.
To start the cooking process manually and have the oven turn off automatically:
Push in and turn the START pointer to the current time of day.
Push in and turn the STOP pointer to the time the oven is to stop.
Turn the oven SET knob to "Time Bake."
Set desired oven temperature.
On most models, the oven cycling light will come on immediately after setting up the time bake cycle. The bake indicator light stays on all the time.
Note: It is not possible to time bake and temperature cook at the same time.