• thermostat is blank
• water leaking from heating or cooling system

In the heating and cooling process, water droplets form at the evaporator coil and collect in a tube. The tube passes runoff water to the drain pan. The pan is equipped with a safety device called the pan float switch, which comes on when the pan is full. This will turn off your HVAC unit to prevent water from leaking on the floor. If the pan is full, there may be an issue with water coming from a frozen coil or a clog in the drain.

• no power in some rooms
• air conditioner won’t turn on
• no power to devices
• heating unit won't turn on
• power is out
• no heat coming from vents
• thermostat is blank

A circuit breaker is the central source of electrical power in your home that supplies your network of electrical control circuits that run power to outlets, lights, alarms, etc with power. When your circuit breaker is overloaded with too much power for one reason or another, it trips. A tripped circuit breaker may cause you to lose power in one room or more, depending on how many rooms are powered by a circuit. It’s important to remember that tripped circuit breakers or blown fuses are not a cause, they are a symptom. Something else is going on with your system to cause it to overload.

• thermostat is blank
• HVAC unit is shut off
• no power to outlets
• no power to devices
• power is out

A GFCI (ground-fault circuit interrupter) is a safety device on some outlets that protects against electrical surges and circuit imbalances. It's designed for circuits in wet areas such as kitchens, bathrooms, basements, garages and exterior outlets. If the GFCI detects an issue, it will trip in a fraction of a second to prevent electrical shock. Once it trips, you won't have power running to your device until the outlet is reset.

• thermostat is blank
• water leaking from heating or cooling system

The condensate pump on your HVAC unit is used to pump out the condensate (water) that the unit produces during the heating/cooling process. In order to work properly, the condensate pump must be plugged in. If it is not, the unit won't function properly.

• thermostat is blank
• no heat coming from vents
• heating unit won't turn on

If your furnace isn't working, the issue could be as simple as a flipped power switch or emergency switch. A furnace switch can also be referred to as a furnace disconnect switch, which describes exactly what it does: disconnects furnace power to turn it on and off when needed. This switch often gets turned off accidentally, in situations such as by a contractor who was performing service, children playing around the furnace, or otherwise.

• HVAC unit is shut off
• thermostat is blank

The thermostat in your home can be powered by various sources, including batteries, HVAC system volt power, and/or a circuit breaker and its corresponding switches and GFCI receptacles. These power sources keep your thermostat on, and while doing so, the thermostat screen should remain on. If the display is blank, there is likely a power loss issue from one of those power sources, but where and why the power disconnected can vary.

• thermostat is blank

A blank thermostat usually means that there is no power running to it. The batteries may be dead.