Boiler will not shut off

S. Domingues

I just replaced the thermostat on a system because the boiler would not stop heating even when i had the thermostat set below the room temperature.
I was wondering what part should i replace next, would it be the part that the thermostat connects to? If so, what is the name of that piece?
I really appreciate all the help you guys have given me, as it was extremely helpful both times i posted here.

lchmb

It depend's on what kind of control system you have or what type or radiant system..Is it one zone only? is it controlled by circulator's....Do you have a control box..just a thought but it may prove cheaper just to have someone stop in and take a peak...

S. Domingues

It is a one zone system, only two wires for the thermostat. I believe it is controlled by circulators, that is what the thermostat wires connect to right?

Weezbo

termostat?

follow the moves:) check the dots it provides a clearer picture.....our crystal ball would ask you what did what when ,try this take the thermostat off,disconnect the wires,is the boiler still running? if so you are on your way to discovery.:)did the boiler quit running? well...whats diffrent in the picture? this information is the easiest way a home owner can help over the phone as it were.