The liquid refrigerant is returned to another heat exchanger where it is allowed to evaporate, hence the heat exchanger is often called an evaporating coil or evaporator. As the liquid refrigerant evaporates it absorbs energy (heat) from the inside air, returns to the compressor, and repeats the cycle. In the process, heat is absorbed from indoors and transferred outdoors, resulting in cooling of the building.

Ductwork pinging or popping. If you hear a pinging or popping sound coming from metal ductwork, this may be caused by thermal expansion or by air blowing past a loose flap of metal. Track along the duct runs, listening for the sound. If you find it, make a small dent in the sheet metal to provide a more rigid surface that’s less likely to move as it heats and cools.

If you need a furnace repaired or an air conditioner serviced, we'll send a local technician out to diagnose the specific problem and recommend solutions for you and your family. There will be a diagnostic fee for the visit, and any specific repairs will be an additional charge. If replacing your system is the best solution, the fee for the diagnosis will be credited toward the purchase and install of a new system.
Given the broad price ranges above, it's easy to recognize that the cost of your furnace repair varies drastically based on which parts need attention. As a result, it makes sense to gain a better understanding of the parts that heat your home, and how much they cost to repair. Repairing or replacing your furnace’s blower motor can cost you anywhere between $150 and $450, depending on the extent of the damage. Heat exchanger repair costs can vary greatly, from as little as $100 for a simple fix to as much as $1,200 for a full replacement. Repairing a furnace igniter will only cost you $300 at most, while flame sensor repairs generally fall between $80 to $250. The average cost to repair your Thermostat will range from $108 to $282.

Circulating refrigerant vapor enters the compressor, where its pressure and temperature are increased. The hot, compressed refrigerant vapor is now at a temperature and pressure at which it can be condensed and is routed through a condenser. Here it is cooled by air flowing across the condenser coils and condensed into a liquid. Thus, the circulating refrigerant removes heat from the system and the heat is carried away by the air. The removal of this heat can be greatly augmented by pouring water over the condenser coils, making it much cooler when it hits the expansion valve.
Furnaces and thermostats are not mix-and-match appliances. Using the wrong type of thermostat with a furnace will cause operating problems and can be dangerous. Although thermostats look similar, they are designed very differently. There are numerous types of heating systems and thermostat systems and they need to be coordinated for safe and proper operation. There are three types of thermostat systems used today: millivoltage, low voltage, and line voltage.​