Trying to run two simultaneous loops that do the same task with different delay cycles I'm trying to control a pellet stove auger motor in such a way that I can use a toggle switch to do High/Low (H/L) - so the way that I have it now is:

 void setup() {
   // initialize digital pin 13 as an output.
   pinMode(13, OUTPUT);
   pinMode(12, OUTPUT);
}

// the loop function runs over and over again forever
void loop() {
  digitalWrite(12, HIGH);
  digitalWrite(13, HIGH);   // turn the LED on (HIGH is the voltage level)
  delay(2850);              // wait for a second
  digitalWrite(13, LOW);    // turn the LED off by making the voltage LOW
  delay(11250);  


Which is just LED on/off but it also controls another relay that controls the blower motor - what I'm trying to set up is a H setting that would be the 2850 delay-ON - and then have say: pin 11 have a delay-OFF of 7000, and have pin 13 still resetting to the delay-ON of 2850.

What I mean is: 


loop A: pin12 on -delay 2850 pin12 off -delay 11250
loop B: pin13 on -delay 2850 pin13 off -delay 7000


I saw and tried the code for 'multi-blink' - as the one I use is pretty much modified 'blink'.

Any assistance would be awesome - I run the one I show above now, on my pellet stove and it was recently -31.4 and worked like a charm, but I'd like to be able to have a high/low option.

PS: I also have a coffee roaster control project as well... help on that one is always appreciated as well.
The Arduino Simple Timer library (and other similar timer libraries) are made for exactly this kind of application. Your setup() routine calls the SimpleTimer library, naming a callback-function and how often it should get called. Your loop function must then call timer.run() reasonably frequently (where 
reasonably frequently" depends on the timing accuracy and jitter tolerance of your application). timer.run() will call each of your callback-functions at its appropriate time. You write the callback-functions to do whatever you need them to do when the timer calls them.

There are one-shot timers and repeating timers - it sounds like your application could one of each per LED: One that fires periodically, to to call a turn-on-LED12 function every (ON_TIME_12+OFF_TIME_12) ms, and a one-shot that calls a turn-off-LED12 function, started by the turn-on-LED_12 function for (ON_TIME_12) msec. Same for LED13, ( ..., etc.)

Your loop function is free to do whatever else, as long as it calls timer.run() frequently enough that your application can meet its timing requirements.