Karen,
Setback devices are not that difficult
to install. Make sure the one you purchase is
designed to control zone heating and follow
the installation instructions (remember to
shut off the power to the furnace to eliminate having your furnace cycling while
you work with the wires). Keep in mind that
hot water boilers have a slow recovery time
when you set the boiler to come back on.
As for your ex- Tell him to measure the
length of the thermocouple and replace it with one of the same length. That should
correct his problem.
Good Luck!