I have model 0155671 but it doesnt look like the model online mine has four buttons across set time plus minus next riw is rnd ctd bottom is manual i dont understand when it says select 12 or 24 hour display\also is pm in military time just cant figure it out

A) 12-24 hour choice >> just use the 24 hour display.
That gives you day and night hours
I don't know why these companies offer 12hr-24hr option on timers.

B) Military time vs Regular time (military time does not use am and pm)
1 1am
2 2am
7 7am
11 11am
12 12noon
13 1pm
14 2pm
20 8pm
23 11pm
24 12midnight

C) Utilitec 0155671 is same as Woods 59377
Before Woods made 59377, they made 49566 (which is also called TD1101 and TD1300)

I think you have Woods 49566
Manual for Woods 49566:
http://waterheatertimer.org/pdf/Woods-49556-TD1300.pdf
Add a comment at any time.



D) How to program timer.
Plug timer in until rechargeable battery is charged and display shows.
Unplug timer to program
1) Set current time.
Hold in reset button for two seconds to clear memory
Press and hold TIME button to select 24 hours so there is no problem. Release Time button.

Press and hold SET button.
MO is flashing, and represents MOnday. TU for TUesday. WE TH FI SA SU
Continue holding down SET button, and press ? ? until current day displays.
Release SET button.

Press and hold SET button again, and Hours will flash
Continue holding down SET button, and press ? ? until current hour displays.
Release SET button.

Press and hold SET button again, and Minutes will flash
Continue holding down SET button, and press ? ? until current minute displays.
Release SET button.

Press SET button again and current time and day will display.

2) Program review:
Set up to 20 on-off programs.
You can select individual days, or groups of days, or all days of the week
For example MO-SU is all days of the week
For each ON time, you also must set OFF time.
So program1 ON is set, then program1 OFF is set
Each ON is set for day, hour and minute
Each OFF is set for day, hour and minute (select same days for OFF and that you chose for ON)
For example if you want timer to turn ON all days MO-SU, make sure OFF time is also set for all days MO-SU.

3) Program the timer:
ON
Press arrow? until display shows PROG 1 ON
This is program1 ON.
Press SET button, but do not hold set button down as you did when setting current time.
The days for program1 ON will be flashing on display.
Press ? ? to select day, or groups of days that you want for program1 ON.

Press SET button again, and program1 ON hour will start flashing
Press ? ? to select hour that you want for program1 ON.

Press SET button again, and program1 ON minute will start flashing
Press ? ? to select minute that you want for program1 ON.

program1 ON is set, next you will set program1 OFF

OFF
Press arrow? until display shows PROG 1 OFF
This is program1 OFF.
Press SET button, but do not hold set button down as you did when setting current time.
The days for program1 OFF will be flashing on display.
Press ? ? to select day, or groups of days that you want for program1 OFF.

Press SET button again, and program1 OFF hour will start flashing
Press ? ? to select hour that you want for program1 OFF.

Press SET button again, and program1 OFF minute will start flashing
Press ? ? to select minute that you want for program1 OFF.

program1 ON and OFF are set, next you will set program2 ON by repeating steps above.

If you do not want to set more programs, that is fine.
Timer lets you set up to 20 programs.

Finish programming: when program ON-OFFs are set, press TIME button and current time displays.

4) Last step:
Push manual override button until AUTO is displayed. This will let timer turn lights on and off.
Plug lamp into timer.
Lamp must be turned ON.
Plug timer into wall.