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Is this a Burnham boiler? Is the pilot lit all the time or do you have electronic ignition?
Ok, first thing to check is the blocked vent switch (see attached pic)which is attached to the bottom of the bell shaped draft diverter. Push the small button between the 2 wires. If it clicks you have reset it and the burner will fire up with any luck. If it doesn't click it wasn't tripped. If that doesn't work I need to know if the motorized vent damper (which is above the bell on the vent) is open.
Is the damper open?
Please answer the question
A call is an additional charge and I have to step away for about an hour soon. If the damper isn't open and the pump is running (assuming 1 pump) then the damper is suspect. If the damper is open try jumping out the rollout sensor just above and outside the burner chamber. If that doesn't start it up then the damper end switch is suspect. Either way, damper not open or open and no fire the damper needs to be replaced.
Go for an aftermarket damper if you have the option since an OEM damper is twice the money.
If you still need a call then let me know and I'll call when I get back.
One other thing to check is the aquastat/limit. Jump the leads on the limit if the damper isn't open. If the damper opens then the limit is suspect.
What is the brand and model of your boiler?
I don't get the 110 voltage reference. The damper is 24 volts. Sounds like you might have a thermostat or thermostat wiring problem. Try jumping the thermostat leads at the transformer (R & G or P & G depending on the age of the boiler)