Official Thermal Zone heating & cooling combined unit parts

How to troubleshoot your Thermal Zone heating and cooling combined unit when it won't start

• Check for electrical power.Check the house circuit breaker for the heating and cooling combined unit to make sure it’s turned on. Reset the circuit breaker if it’s tripped.
• Check the condensate drain.Heating and cooling combined units often have a float switch mounted on the evaporator condensate drain pipe that shuts off the air conditioner if condensate water isn't draining. Shut off power to the heating and cooling combined unit and check for condensate water backing up in the evaporator drain system. Clear the drain to reset the float switch and restore power to the heating and cooling combined unit.
• Check the thermostat. Make sure you have the thermostat set correctly. Adjust thermostat settings if necessary. If the thermostat doesn't have power, check its wiring and reconnect any loose wires. Replace the thermostat if it isn't working.
• Examine the electronic control board. Disconnect electrical power to the heating and cooling combined unit and check the electronic control board wiring connections. Reconnect any loose wires and repair any broken wires. Check for burn marks on the circuit board and replace the electronic control board if you see burnt spots or melted wires.

How to diagnose common Thermal Zone heating and cooling combined unit problems

Here are some heating and cooling combined unit problems you might run into, and what to do about them.

• Won’t turn on. Check the house circuit breaker for the heating and cooling combined unit to make sure it’s turned on. Reset the circuit breaker if it’s tripped. Low air flow can also prevent the heating and cooling combined unit from working, so check the air filter and replace the filter if It’s clogged with lint. Check for a clogged evaporator condensate drain pipe because a drain clog can cause the heating and cooling combined unit to shut off.
• Lack of air flow through the vents. A clogged air filter can prevent air from flowing through the vents, so replace the air filter if it’s clogged. If the filter isn’t clogged, a problem with the blower fan may be causing low air flow through the vents.
• Makes lots of noise. Bearings in the blower fan can make loud squealing or screeching noise when the heating and cooling combined unit runs. Replace the blower fan if its bearings make noise while the fan runs.