duel fuel and water heater?

Hello
I have a wood/oil burning furnace and an oil fired water heater.
I have not used the oil furnace all winter and am burning wood for heat.
My water heater has worked fine all winter but I must have just run out of oil at the fillup as I noticed I was not hearing the water heater burner come on.
The water tank is an Irving and the burner an "Aero"? and are over 10 years old.It has a large red "inset"reset button on one part of the burner and a smaller red button on another part.
I am trying to determine how to bleed the fuel line and if both burners need to be bled? and is it safe to go through the process while burning a wood fire?
I do see the bleed valves on the water heater burner but not on the furnace (Newmac non grated) 5 years old.
I have not been able to open the valve at all..it is very tight.