How to set it to come on at 1.30am whatever the length of the program. i have a 24hour timer on the plug which is set to start at 1.30am but my new machine doesn't start!

not sure if this will help you at alI, but I found this answer on the following website: .askmehelpdesk.com

and an answer to a similar model here: http://www.intermatic.com/images/misc/158ej12685ref.pdf Good luck

Plug in timer - The letter C will Flash

TO SET CURRENT TIME:
Press Time Button - It will advance to 1 a.m.
Continue pressing until right time to the nearest hour.
(NOTE: A dot at the bottom right corner of the display indicates P.M. hours).

TO SET ON AND OFF TIMES FOR TIMER OPERATIONS:
Press Mode button - Letter P will flash inviting you to set the program
Press Time button repeatedly until required staring time appears in the window. (starting time is now displayed).
Press Mode button again - the letter E now flashes.
Press time button repeatedly until required ending time appears in the window. (Note: a dot at the bottom right corner of the display indicates P.M.hours).
Press Mode button and the display returns to the current time.

Programming is now complete. You may now plug in whatever needs to be turned on. The device will turn on and off automatically every day at the times you have just selected.

TO REVIEW THE PROGRAM
Press time button - Displays successively, for 1-2 seconds each: P, starting hour and E, ending hour. Then returns to show the current time..

TO CHANGE YOUR PROGRAM
Unplug the timer, which will discontinue the current program. After 10 seconds, plug it in again and proceed to set current time. Then continue with the programming steps as above.

FOR MANUAL OVERRIDE
Pressing the Mode button at any time will turn on the devices plugged into the timer. The display will indicate the letter O. The devices will remain on until the ending time of the daily program. To return the timer to the automatic mode prior to that hour, press the Mode button again. The display will return to show the current time.

AFTER A POWER INTERRUPTION/FAILURE
The timer will return to displaying a flashing C and the devices plugged into it will be off

FM1D single-channel timer is difficult to program.
Open following links to identify timer and download manual:
http://waterheatertimer.org/Intermatic-timers-and-manuals.html#GM40AVE
http://waterheatertimer.org/pdf/fmd-20-setpoint-programming-guide.pdf

Timer flowchart starts page 3.
First step is to select format and then set current time.
Format is asking if you want 24hour or 12 hour format:
12 hour is am and pm
24 hour is military time where 11pm at night is hour 23.
Current time is simply the time right now.

Next step is to set program 1 thru 20 (P01 P02 thru P20)
Start by pushing +/- until desired program displays
Each program is set for either ON or OFF.
There are 20 memories available: 10 ON and 10 OFF.
Not necessary to use all 20 memories.
You need to set at least 1 ON time and 1 OFF time.

Make chart of on-off schedule to avoid conflicts in programming: For example ON at 7am Monday and OFF at 9am all-days-of-week will cause timer not to function as expected.
Each ON time is set for hour, minute and day.
Each OFF time is set for hour, minute and day
Press menu to terminate programming.

Add a comment for specific help with this timer.

Set switch to timer on.
Rotate timer to correct time of day.
Push in pins for whenever you want the device to run.
Plug it in.

Manual and image for Woods/Noma N1506 outdoor timer
http://waterheatertimer.org/Woods-timers-and-manuals.html#N1506

SETTING NOMA N1506 TIMER

Plug in timer - The letter C will Flash

TO SET CURRENT TIME:
Press Time Button - It will advance to 1 a.m.
Continue pressing until right time to the nearest hour.
Timer is only set to nearest hour.
(NOTE: A dot at the bottom right corner of the display indicates P.M. hours).

TO SET ON AND OFF TIMES FOR TIMER OPERATIONS:
Press Mode button - Letter P will flash inviting you to set the program
Press Time button repeatedly until required staring time appears in the window. (starting time is now displayed).
Press Mode button again - the letter E now flashes.
Press time button repeatedly until required ending time appears in the window. (Note: a dot at the bottom right corner of the display indicates P.M.hours).
Press Mode button and the display returns to the current time.

Programming is now complete. You may now plug in whatever needs to be turned on. The device will turn on and off automatically every day at the times you have just selected.

TO REVIEW THE PROGRAM
Press time button - Displays successively, for 1-2 seconds each: P, starting hour and E, ending hour. Then returns to show the current time..

TO CHANGE YOUR PROGRAM
Unplug the timer, which will discontinue the current program. After 10 seconds, plug it in again and proceed to set current time. Then continue with the programming steps as above.

FOR MANUAL OVERRIDE
Pressing the Mode button at any time will turn on the devices plugged into the timer. The display will indicate the letter O. The devices will remain on until the ending time of the daily program. To return the timer to the automatic mode prior to that hour, press the Mode button again. The display will return to show the current time.

AFTER A POWER INTERRUPTION/FAILURE
The timer will return to displaying a flashing C and the devices plugged into it will be off.

Manual and image for Woods/Noma N1506 outdoor timer
http://waterheatertimer.org/Woods-timers-and-manuals.html#N1506

SETTING NOMA N1506 TIMER

Plug in timer - The letter C will Flash

TO SET CURRENT TIME:
Press Time Button - It will advance to 1 a.m.
Continue pressing until right time to the nearest hour.
Timer is only set to nearest hour.
(NOTE: A dot at the bottom right corner of the display indicates P.M. hours).

TO SET ON AND OFF TIMES FOR TIMER OPERATIONS:
Press Mode button - Letter P will flash inviting you to set the program
Press Time button repeatedly until required staring time appears in the window. (starting time is now displayed).
Press Mode button again - the letter E now flashes.
Press time button repeatedly until required ending time appears in the window. (Note: a dot at the bottom right corner of the display indicates P.M.hours).
Press Mode button and the display returns to the current time.

Programming is now complete. You may now plug in whatever needs to be turned on. The device will turn on and off automatically every day at the times you have just selected.

TO REVIEW THE PROGRAM
Press time button - Displays successively, for 1-2 seconds each: P, starting hour and E, ending hour. Then returns to show the current time..

TO CHANGE YOUR PROGRAM
Unplug the timer, which will discontinue the current program. After 10 seconds, plug it in again and proceed to set current time. Then continue with the programming steps as above.

FOR MANUAL OVERRIDE
Pressing the Mode button at any time will turn on the devices plugged into the timer. The display will indicate the letter O. The devices will remain on until the ending time of the daily program. To return the timer to the automatic mode prior to that hour, press the Mode button again. The display will return to show the current time.

AFTER A POWER INTERRUPTION/FAILURE
The timer will return to displaying a flashing C and the devices plugged into it will be off.

You posted under Woods plug-in timer.
Several brands sell identical or similar timer.
If this is not your timer, look through following page to identify your timer
http://waterheatertimer.org/Woods-timers-and-manuals.html

Add a comment any time.

To set timer.
Rotate dial until current time lines up with arrowhead; when plugged in, the dial rotates
Notice 24-48 gray-colored segments located around edge of dial; each segment is 1 hour
Segment pulled up = lights OFF
Segment down = lights ON
Some brands, the segment-up is ON instead of OFF

Notice override switch located top of timer, move switch to TIMER for programs to run.
Plug lamp into timer, plug timer into wall
Lamp must be turned-on

If your timer is not operating, then timer could be defective.

Check the following:
Light is turned to ON position.
Light bulb is not burned out.
Current time lines up with arrowhead located on inner dial.
Override button on top of timer is moved all the way over to TIMER.
Receptacle has power.
Circuit analyzer shows circuit is good.
Segments are pulled all the way up (around 1/4 inch or a bit less)
Dial is rotating as time passes.
If all these things check out and timer is still not functioning, then timer is defective.

According to another fixya answer posted December 4 2009:

SETTING NOMA N1506 TIMER

Plug in timer - The letter C will Flash

TO SET CURRENT TIME:
Press Time Button - It will advance to 1 a.m.
Continue pressing until right time to the nearest hour.
(NOTE: A dot at the bottom right corner of the display indicates P.M. hours).

TO SET ON AND OFF TIMES FOR TIMER OPERATIONS:
Press Mode button - Letter P will flash inviting you to set the program
Press Time button repeatedly until required staring time appears in the window. (starting time is now displayed).
Press Mode button again - the letter E now flashes.
Press time button repeatedly until required ending time appears in the window. (Note: a dot at the bottom right corner of the display indicates P.M.hours).
Press Mode button and the display returns to the current time.

Programming is now complete. You may now plug in whatever needs to be turned on. The device will turn on and off automatically every day at the times you have just selected.

TO REVIEW THE PROGRAM
Press time button - Displays successively, for 1-2 seconds each: P, starting hour and E, ending hour. Then returns to show the current time..

TO CHANGE YOUR PROGRAM
Unplug the timer, which will discontinue the current program. After 10 seconds, plug it in again and proceed to set current time. Then continue with the programming steps as above.

FOR MANUAL OVERRIDE
Pressing the Mode button at any time will turn on the devices plugged into the timer. The display will indicate the letter O. The devices will remain on until the ending time of the daily program. To return the timer to the automatic mode prior to that hour, press the Mode button again. The display will return to show the current time.

AFTER A POWER INTERRUPTION/FAILURE
The timer will return to displaying a flashing C and the devices plugged into it will be off.

GE timers at Jasco:
http://www.jascoproducts.com/support/manual-downloads/index.asp

Type in your keyword search for 'Timers' and the manuals show.
Add a comment if you are still having a problem, I specialize in timers

http://www.jascoproducts.com/support/manual-downloads/applications/DocumentLibraryManager/upload/Outdoor-15107-Manual-eng-spn.pdf

Above is link to GE 15107 manual
This is a 15amp timer that can handle up to 1440 watts

How to set timer
Rotate center dial to set current time
Line up current time with triangle on inner part of dial
The timer dial shows nighttime hours on dark part of dial, daytime hours show on light part of dial
The timer dial rotates like a clock after it's plugged in
The outside edge of timer dial has 48 segments
Lift up these segments for times you want timer OFF
Segments down for timer ON

Segments up, timer OFF. Segments down, timer ON.
Segments in photo are on the GE 15207 timer

SETTING NOMA N1506 TIMER

Plug in timer – The letter C will Flash

TO SET CURRENT TIME:
Press Time Button – It will advance to 1 a.m.
Continue pressing until right time to the nearest hour.
(NOTE: A dot at the bottom right corner of the display indicates P.M. hours).

TO SET ON AND OFF TIMES FOR TIMER OPERATIONS:
Press Mode button – Letter P will flash inviting you to set the program
Press Time button repeatedly until required staring time appears in the window. (starting time is now displayed).
Press Mode button again – the letter E now flashes.
Press time button repeatedly until required ending time appears in the window. (Note: a dot at the bottom right corner of the display indicates P.M.hours).
Press Mode button and the display returns to the current time.

Programming is now complete. You may now plug in whatever needs to be turned on. The device will turn on and off automatically every day at the times you have just selected.

TO REVIEW THE PROGRAM
Press time button – Displays successively, for 1-2 seconds each: P, starting hour and E, ending hour. Then returns to show the current time..

TO CHANGE YOUR PROGRAM
Unplug the timer, which will discontinue the current program. After 10 seconds, plug it in again and proceed to set current time. Then continue with the programming steps as above.

FOR MANUAL OVERRIDE
Pressing the Mode button at any time will turn on the devices plugged into the timer. The display will indicate the letter O. The devices will remain on until the ending time of the daily program. To return the timer to the automatic mode prior to that hour, press the Mode button again. The display will return to show the current time.

AFTER A POWER INTERRUPTION/FAILURE
The timer will return to displaying a flashing C and the devices plugged into it will be off.