according to the op manual you have a standing pilot...meaning you have to light it with a match.shut the toggle 115V switch off on the side of the boiler and remove the front cover so you see the burner section.on the gas line control valve there is a dial ON/PILOT/OFF should be in the ON position at this point.turn the dial to PILOT(need that shut off "open" just outside the boiler also)set yourself up with a match so you can reach into the boiler where that silver aluminum line ends that is the pilot assembly.light the MATCH.........push the dial down on the gas valve and hold it down(with thumb)reach in,and the pilot assembly should light like on the old style stoves

.....or bic lighter

.NOTE don't worry about the main gas coming on 1......the 115Vtoggle is off right,and 2 the main gas valve is in the pilot position.so we have the pilot lit ........

keep holding that dial down count to 30 as with those "mississippi"

and then let it go should pop up....and that pilot should stay lit...YES.turn the dial to ON put the toggle 115V up flue damper should open CLICK!!!the main burner should come on.you have a automatic vent damper on the flue pipe on the back of that boiler with that toggle 115V back on that should cycle open,and "CLICK" the burner in.....make sure that stat is calling.the way the boiler works as page #8 reviews the stat calls the flue damper moves to open and the "CLICK" tells the boiler its main burner can start because the flue is open...bigtime saftey there....you have to here a click within the boiler when that damper swings to open..do the pilot thing first i will check back
http://www.slantfin.com/documents/411.pdf