You should call Dish and ask for a "hit". The few-sec procedure plus possible a few minutes to get it from the satellite will take 10-15 minutes of dialogue thru the CSR. Beforehand be sure you have done the reboot and if possible check if another disk or recorder will work. If some will and some won't then the hit is what you need.
It will change the household key in Menu+6+3+PageDown several times. You probably want all recorders powered to standby or fully on when the signal comes. It will not interrupt recording or playing. But try to do it when not recording to be sure.
BTW the household number will be the same (less the last digit or so) on each recorder--you cannot set that number.
Of my 3 (722+722+622), 2 are the same, 1 off a bit.
-Ken