No heat this morning

[Saltheart]

Yep , forced hot water. Turns out some repair guy in the past (have no idea how far back) replaced the flue damper which then required a new aquastat but instead he did a jury rigged wire jumper to keep the old aquastat. That jury rigged jumper finally gave out. This guy today put in a new Aquastat (correct model for the damper) . I just hope that's the end of the problem. I'm too busy this week to be dealing with a recurring heating system problem.

[5/0]

The damper has too functions to it,one is to prevent cold air from rushing into the boiler after the call for heat has finished,this is to stop the cool air cooling the heat ex changer.
Second function is for safety,if the damper dosen't open the unit will not fire up and dump Co2 into the dewling.This damper should have a by pass switch on it for Auto or manual mode,, this if supported should be located on the plastic housing.when the 24volt motor dies you can manually open the damper and move the switch to manual mode.
If the circuit board chit's the bed you now have to put a jumper in place,there are four wire's and it is important to jump the right one's,if not the unit will run till the cow's come home........causing the T&P to dump water/pressure over load.
The aqua stat is a key factor for you're boiler this will detect actual boiler water temp, as the probe sit's into a well,on a call for heat this will turn on the circ pump for several seconds to move the water in the loop(s)then it'll send 24 volts to the solenoid in the gas valve to release the hounds.

Glad to hear you got youre heat back on line,I hope his price's were reasonable.