OK, if the primary controls light is not lit, it either means you do not have power to the control or the control is bad...
First varify power to the control, if the fuse/breaker is good, than the next step is the emergency shut off switch {there should be one outside the boiler room or at the top of the stairs}, then the power should go to an electric "fire'o'matic" switch which will be mounted above the boiler/furnace and depending on the units age will either be an eye type or a twist type {the twist type has a tendancy to loosen and or be faulty after time}, then the power should go to a service switch which will be mounted to or near the boiler/furnace... That would be the first place to check for power, if there is power there move on to the next place it goes {which depends on the system, a furnace will go to the fan control, and a boiler will go to the aqua stat control}... If you have power all the way to the control and you varified that your thermostat {tt terminals} are closed, next check for power to your burner motor leads... If there is no power to the motor leads and power to the control with the controls tt terminals closed you need a control, which for the riello is around $150...
Irvin
November 2008