Hey

Not really...

as i understand his question, (or at least as i want to understand it)

then he have 24Vdc for the heating, then he want to make +/-12V and 5V out of the 24V galv. isolated.

the psu i have it rated to 3*600mA at 5V, so it is just to put a 3W(5W or transistor coupled) zener across the output supply, and it wil drag down the supply.

Kasper

btw, the supply is ofcause only regulated on one of the channels.