We need clear instructions for setting the timer

http://waterheatertimer.org/How-to-set-timers.html

If your timer is not shown on link above, please re-post question with clear photo of your product

Gene

Water Heater Timers Save Money

If you need further help, I’m available over the phone at https://www.6ya.com/expert/gene_9f0ef4df2f9897e7

Give us the model number so we can see what you're talking about. Tell us what link you have tried, and how the instructions seem to be different.

Display showing no-op is sometimes associated with defective timer, bad battery. Resetting timer will clear memories and restore functionality in some cases.
http://waterheatertimer.org/How-to-troubleshoot-timers.html#digital
Attach photo of timer, or description of timer.
Add if this is new timer or if timer worked before, and what load the timer controls
Do you have correct instructions for timer ?... scan the manual into .pdf format. and then post the .pdf manual on your website .... then post link here to assist other folks with same problem.
http://waterheatertimer.org/How-to-troubleshoot-timers.html#digital

Gene

Water Heater Timers Save Money

If you need further help, I’m available over the phone at https://www.6ya.com/expert/gene_9f0ef4df2f9897e7

1) Copy following link to help identify timer and download possible manual:
http://waterheatertimer.org/Woods-timers-and-manuals.html#outdoor

2) After viewing link above, add a comment with clear detail about timer

If you need further help, I’m available over the phone at https://www.6ya.com/expert/gene_9f0ef4df2f9897e7

1) Copy following link to identify timer, and instructions for setting analog timers bu experimenting with features:
http://waterheatertimer.org/Woods-timers-and-manuals.html#outdoor
http://waterheatertimer.org/How-to-set-timers.html

2) If you have different timer, then view page for possible match, and/or add comment with clear description of timer.

If you need further help, I’m available over the phone at https://www.6ya.com/expert/gene_9f0ef4df2f9897e7

Intermatic does not post that product manual, or the door label for that specific product. Nor is the door label clear when viewing images of timer.

Copy following links for possible assistance wiring timer, and then setting timer:
http://waterheatertimer.org/pdf/RC2403RT-Door Label.pdf
http://waterheatertimer.org/How-to-set-timers.html

If you need further help, I’m available over the phone at https://www.6ya.com/expert/gene_9f0ef4df2f9897e7

Question does not describe the timer.
Web search for et220 does not show image of timer for clear identification.
My files do not show et220
Question posted under 24-hour analog timer.

1) Open following link for possible instructions:
http://www.fixya.com/support/t1329823-first_alert_timer_et220

2) Add a comment with clear description of timer for possible identification and instruction manual.

3) Post a photo of the timer on Flickr. Add a comment with link to photo for possible identification and instruction manual.

4) Maybe possible to e-mail the company for instructions: [email protected]

Open following links to identify timer and read instructions.
If this is not your timer, or instructions are in error, then add a comment with clear description of timer for possible help.
http://waterheatertimer.org/pdf/Sunbeam-61048-countdown-timer.pdf
http://waterheatertimer.org/Woods-timers-and-manuals.html#FM1D

You posted under ST01C Intermatic battery operated timer.
If you have different timer, then add a comment.

Let's review ST01C timer for a moment.
Programming will stay inside timer memory indefinitely until timer no longer works.
Even if battery is removed, programs remain. Current time setting does not remain in memory.
If battery goes dead, then current time will disappear, but programs remain forever.

If previous programming was correct, you might only need to set current time,.
In that case, you do not want to 'reset' timer and clear memory.

If you want to clear old programming entirely, then you can 'reset' timer using following instructions.
Press and hold on-off button, and then use paper clip to push in reset button for 3 seconds.
Release reset button but keep holding on-off button until INIT displays momentarily.
Release on-off button.
If display does not show, then timer battery is bad, or timer is bad.

For instructions how to set current time, click link below.
In addition to current time, the link has ST01C manual and also has EZ to follow instructions and photos for setting on-off times (but not astro times)
http://waterheatertimer.org/ST01C-program.html

Instructions are different for astro dawn to dusk.
Add a comment at any time if you need free help with specific steps in the manual.

If you do not want to read the manual or open a link and read the steps or add a comment for further free help, then you can pay a fixya expert for phone support and that person will walk you through the steps while on the phone.
Keep in mind that ST01C timer has 1 year limited warranty, and your timer might be broken.
In that case you should try the free steps first.

Clearing event on Utilitec 7-day timer:
Tiny print on instructions say: press PROG button several times to locate setting you want to clear > Press and hold MODE button > press PROG button to clear setting > to finish, press CLOCK button and display will show time of day.

In case of operational failure:
Tiny print on instructions say: press RESET button to clear all settings >> and then reprogram

If it's the same as ours (clock button top left, clear bottom left):

1. press and hold clock until the clock starts to flash
2. set time using h/m/s keys
3. press clock again

Hope it works