No lights for call for heat on s8610u but my dampener opens and closes like it should.

If you have only one transformer and your damper motor works, it is not the transformer.

Check pressure control, low water cut off, blocked vent switch and burner flame roll out fuse.

Has the pigtail been cleaned recently?

If the transformer was bad, the damper wouldn't operate.

There's a little switch on the damper. Raise the thermostat so the damper opens. When the damper is fully open, flip the switch to manual. If that starts the burners, then it's a bad end switch in the damper. It's safe to leave the damper open until you can get a replacement.

Is the circulator running? If not, it's likely NOT the end switch in the damper, but maybe the relay.

If the circulator is running, and switching the damper to manual doesn't do it, then a safety probably tripped and you'll need a qualified tech.

Sorry, yeah, I mentioned circulator but the OP mentioned a PressureTrol.

According to the wiring diagram, the only thing that will keep the auto vent damper from operating is the thermostat and the pressure control. So those two items are not the problem. Once the damper is open there is a safety switch that closes in the damper. That is the first thing to check. Is that switch closing to send 24 VAC to the burner circuit? That is done by attaching your 24 VAC meter leads as shown in the diagram.

If you do not get 24 VAC at the wire nut or the 1 terminal on the LWCO, then you have a bad damper motor and that needs to be replaced. If you do get 24 VAC at the 1 terminal then you follow the circuit to the 5 terminal on the LWCO.

This is the next stop on the electrical train to the gas valve. If the water is low, then add water. If you get 24 VAC to on the LWCO then move to the next stop. That would be the Roll Out switch, Purple then Blue then to the Spill Switch Green then Yellow Then to the S8600 5 terminal (24 V) Red Lead.

When you stop getting 24VAC reading on the meter, you have found the open contact or broken wire. That is what you need to fix.

What make and model boiler is it?

When you jump across the roll out switch, does the burner operate?

If yes, then you need to find out why the rollout switch tripped. Is the vent blocked, is the HX blocked? Was/Is there a downdraft in the flue or the flue connector?

Those safety devices are there for a reason. You need to find the reason it failed!

This is your part. It is a fusible link. One and done.

https://www.supplyhouse.com/Utica-Dunkirk-14629002-291F-Thermal-Cutoff-Rollout?_br_psugg_q=14629002

Get two they are small.

You may need a mirror and a flood light to look up inside the heat exchanger for a blockage of carbon/soot build up between the cast iron sections.

It definitely sooted up, @Joeguy. Time to call a pro. Where are you located?

There is carbon in between the cast iron sections. you need to do two things,

1. Remove that soot
2. Find out why that soot got there in the first place.

To remove the soot, you will need to remove the vent damper (16) top cover (13) and then the flue collector (14) to access those flue passages with boiler cleaning brush and a SootMaster vacuum or a shop vac with a extra collector bag.

You may want to remove the burners at the bottom to clean them and vacuum out the combustion chamber (5) before replacing the cleaned burners. This is a real project and you may want to get a Pro to do it. The guys that work on oil burners have the necessary tools to do this job.

Once the boiler is cleaned and back together, you will fire up the burner and need to have the flame tested with a combustion analyzer (another expensive tool that oil burner guys have) to see why the flame made so much soot the leat time it was operational.

You will want to look at what has changed around the system since the last time it operated properly.

1. Has a tree grown higher that the top of the chimney?
2. Was the basement refinished/remodeled?
3. Was there an exhaust fans added to the building?
4. Was any work done in the home that created excessive dust to accumulate on the burner air intake?
5. Was the home insulated new windows installed or sealed up in any fashion?

These items and more can cause there to be insufficient combustion air. Without enough air for combustion the flame will burn rich, and dirty, and leave massive amounts of soot behind.

You have a dangerous situation with that boiler. That fusible link saved everyone in your home from carbon monoxide poisoning. You need to get it professionally repaired by someone who is trained in combustion analysis and equipped with a digital combustion analyzer. I don't think this is something you should attempt to DIY.