I am staging the oil boiler so its a backup heat if coal boiler is unable to keep up with loads, or if coal goes out. Plus oil boiler will be set for a low core temp for DHW coil.
So to make the 3250 just run the circulator to primary loop at XXX degrees, off at XXX i need to ?? 1 use the boiler B1 B2 to run circulator, and switch the Zone/Indirect switch to zone and TT jumped? therefore it only uses the aquastat bulb for cycling the circulator? This unit will be mounted on coal boiler, using its temperature to activate the water from oil boiler into primary loop when needed.
Is am correct with wiring of circulator and TT terminals in 3250 to have it run this way.
heres the link to hydrostat install manual. http://www.hydrolevel.com/pages/pdf_files/hydrostat_3250_instructions.pdf