4 posts, read 42,523 times 25,521 posts, read 52,492,518 times 3,632 posts, read 7,226,434 times Originally Posted by TrapperL Not true- A main disconnect on the exterior is required today, but that may have not been the case when OP's house was built. It's not a "sub-panel" it would be the main breaker/fuse panel. If you have a breaker/fuse in the main panel, why would you ALSO have breakers/fuses outside- Wrong! If there are breakers/fuses in the main panel, there are "disconnects" at the unit. If there are NO breakers/fuses in the main panel they will be at the unit(s). 804 posts, read 2,720,065 times Typical MAIN panel box as per requirements of the second largest electrical supplier in the Southwest. Inside the MAIN panel box. Note breakers for 220V only in this box which are the range/stove, A/C compressor in this case, and to the subpanel box. Typical SUB panel box as accepted by the second largest electrical supplier in Texas.

This one is in the garage which is fairly typical for new construction. Note double breaker on lower left of box. Typical air handler installation. All residential air handlers are 110V, just like this one. Note 110v duplex receptacle for power. In the case of this house, there is no breaker at the compressor as the unit is within 5ft of the main panel box. Otherwise, a correct breaker of the correct size is required by code in a box no farther than 5 ft from the compressor. You may substitute a breaker cutoff which is a handle affair that all you have top do is pull it and the handle comes out cutting off the electricity. They are a one time use part and the entire unit replaced if you pull it. Breakers are reusable and in the case of these units, provide additional backup and convenience of being able to turn the unit off and on without cost. 333 posts, read 891,606 times 342 posts, read 947,030 times Originally Posted by QIS Furnaces generally don't plug into a wall receptcale.

The air conditioner is outside the home and the furnace is inside. To diagnose heating, ventilation and air conditioning problems, start with the easy, visible items and work your way to the hidden components. An HVAC consists of a furnace, an air conditioner, ductwork and a fan connected to the ductwork. air handling unit selection procedureThe thermostat controls these elements by signaling them to turn on or off based on programmed settings. ac unit for a 1500 sq ft houseAs part of the ventilation system, a filter sits inside the cold air return that removes contaminants from the air before heated or cooled air is distributed throughout the home. wall ac unit filterDiagnosis Begin your diagnosis of the HVAC system by verifying that it has power.

Locate the service panel and ensure the circuit breaker has not tripped. The furnace and the air-conditioner each have their own dedicated circuit breaker or fuse. Turn the circuit breaker off for the unit that is malfunctioning. Wait about 10 seconds and switch it back on. If you have fuses instead of circuit breakers, switch the main power off. Remove and replace blown, burnt or broken fuses. Next check the thermostat for power. Some thermostats receive power via the electrical system, while others contain batteries. Remove and replace batteries for battery-powered thermostats if there is no power at the unit. Furnace Switch the thermostat to "heat" mode and set the thermostat 3 to 5 degrees above the room temperature. Wait at least 30 seconds before checking for heat at an open register. If no heat comes out, turn the thermostat off. Confirm that the panel door on the furnace is closed. A switch inside the panel door allows the system to operate when it is fully engaged. If not engaged, the heater won't come on.

Reset the furnace by opening the panel door and turning off the gas or pushing the reset button. Wait five minutes -- or follow the instructions in the unit's manual for reset -- then turn the gas back on. Air Conditioner Set the thermostat to "cool" mode. Adjust the thermostat setting 3 to 5 degrees below the room temperature. Locate an open register and check for cool air after waiting for 30 seconds. Reset the air conditioner at the circuit breaker. If the air conditioner was running, but stopped producing cold air, check the air conditioner for water below the unit. If there is water, dirty coils can cause the coils to freeze. Turn the air conditioner off at the thermostat and circuit breaker, let the unit sit for three hours, then clean the coils and restart the unit. Ventilation Ensure the fan is on at the thermostat and the registers are open. Newer thermostats have two settings for the fan: "on" and "auto." When set to "on" the fan will run continually. When set to "auto" the fan kicks on with the heater or air conditioner calls for it.

Locate the cold air return and remove the filter. Examine the filter for dirt. Cold air return filters must be clean for the system to operate efficiently. If your filter is a permanent one that requires cleaning, follow the steps in the owner's manual. Locate the arrow on one side of the filter that shows the direction the air flows. After cleaning, ensure that you put the filter back with the arrow pointing toward the ductwork inside. Replace the disposable filter with a new one. If the registers for the ventilation system do not deliver air, locate the blower motor and check the belt for cracks or breaks. References Hannabery HVAC: Heating Troubleshooting ChecklistTrane: Troubleshooting Photo Credits Jupiterimages/Comstock/Getty Images Suggest a CorrectionHow Lightning Strikes Affect Your Air Conditioner No matter the time of year, a thunderstorm can be unnerving for pets, children, and those who fear the loud boom of thunder and the bright flash of lightning. Even more frightening is the idea that a nearby lightning strike can affect your home’s electrical wiring, including your HVAC unit.

Arkansas has 100 days of precipitation a year on average, which means it’s highly likely that a nearby lightning strike during a thunderstorm can damage electrical and plumbing fixtures. The initial lightning strike isn’t generally what damages HVAC units right away—it’s the power surges following an outage that can cause air conditioners to receive damage in a storm. A power surge is a spike in voltage and varies in both duration and magnitude. While most homes use 120-volt, 60 Hz, single phase electric power, a power surge spikes the voltage to 169 volts, causing damage to appliances and electronics that rely on that power to work. When lightning strikes damage an air conditioning unit, the effect may not be immediately apparent. Over the course of a few months following a nearby lightning strike, you might notice your air conditioner doesn’t work as well. Here are a few problems with your air conditioning to watch for following a lightning strike: Damaged capacitor: The most common air conditioning part to give way following a power surge, a damaged capacitor can lead to further problems, including compressor failure.

Blown fuses: If the voltage has damaged your air conditioner, you are more likely to encounter an air conditioning system which trips a breaker or blows the fuse due to damaged electrical lines. Burned wires: If a power surge damages electrical wires within the air conditioner or within your home, your air conditioner might not work. Damaged compressor: One of the most expensive parts to fix in an air conditioning unit, a damaged compressor may not be noticeable right away. It can take weeks or months for an air conditioning unit to finally fail and indicate that the compressor was damaged. It’s important to have your HVAC unit inspected following a lightning strike to avoid more expensive replacements down the road. How do you prevent damage to air conditioners following a lightning strike? For starters, it’s not possible to entirely prevent electrical damage from lightning strikes. Since we can’t predict when or where lightning can strike, the best you can hope for is little to no damage to your home if the worst happens.

If a direct lightning strike damages your air conditioner, for example, there would have been little you could have done to stop it. You can, however, take steps when a thunderstorm is predicted to prevent harm from power surges. First, it’s important to use outlet surge suppressors between appliances and the electrical outlet. This minimizes the damage left behind by power surges and can protect your devices from the effects of a surge. Second, you might consider panel-mounted surge protection to reduce the damage to your home’s electric gateway. Surge protection for your entire home is a good investment to save wiring and appliances from the damage a lightning strike can cause. Finally, to prevent damage to your air conditioning unit, turn off the air conditioner at the thermostat during a lightning storm. If power is not running to the unit when the lightning hits nearby, it’s less likely that there will be serious damage than if the unit was turned on. Don’t wait until it’s too late to have your air conditioning unit inspected following a lightning strike.