ThermGuard is compatible with all 24 volt heating systems.  ThermGuard is not compatible with electric baseboard heating systems or millivolt systems.  If you are unsure what type of system you have please contact a qualified heating contractor.  These installation instructions are specific to systems with dedicated fan switches.  If your system is lacking a fan switch, please contact Bear Mountain Design for additional instructions.

The only tools you will need are a screwdriver (either slotted or Phillips; to match the screws on your thermostat) and a sharp knife or wire strippers to strip wires.

Test to be sure your existing system is working properly by turning the fan on with the fan switch and verifying that the system fan operates.  If not, contact your local heating service repair company before proceeding.

TURN OFF POWER to the system at the boiler, or at the fuse/circuit breaker panel.

Once the front of the thermostat is removed, look for two screws that connect with the wires coming from the wall.  On some thermostats, the thermostat must be removed from the wall to access the screw terminals.  In this case, once the front of the thermostat is removed, unscrew the thermostat back from the wall and look for the screws.

There are two wires on the top of ThermGuard that must be connected to your existing thermostat.  These wires should be connected to the terminals labeled R (or RH) and G.  It doesn’t matter which ThermGuard wire goes to which terminal.  Just connect them in the most convenient manner.  This connection can be made by loosening the screws that hold the existing wires and inserting the ThermGuard wires with the existing wires.  Please be sure both sets of wires are secured in place by tightening the screws back down.

If the thermostat back was removed from the wall, carefully replace the back of the thermostat and be certain it is replaced level.  This is very important on mercury-switch thermostats.

Make sure that the wires from ThermGuard do not interfere with the movement of the thermostat.  If necessary, tape the wires to the thermostat back.

Replace the cover on the thermostat.

Position ThermGuard below the thermostat and remove the backing of the double-stick tape.  Securely position ThermGuard to the wall by gently applying pressure to the front of the unit.

Verify the ON/OFF switch on ThermGuard is in the OFF position.

Turn on power to the system at the boiler, or at the fuse/circuit breaker panel.