Understand how Cased A-Coils interact with furnaces and other heating unitsUpdated 19 hours ago

Introduction

This article provides an overview of how Pioneer’s Cased A-Coils interact with furnaces and other heating units. You can pair Cased A-Coils with a furnace or the Pioneer YH Series heat pump condenser central split units to create a desirable setup.

Despite being described as an installation with the furnace, the A-Coil is technically part of the heat pump or air conditioning system. The A-Coil is often installed with the furnace because the furnace’s blower fan is used to circulate air over the A-Coil and throughout the house.

Furnace and A-Coil Connection

• The A-Coil, which is also known as an evaporator coil, is usually installed on top of a gas furnace. In certain cases, the A-Coil can be installed below the furnace.
• Air passes over the A-Coil after being circulated by the furnace’s fan.
• The heat pump system fills refrigerant into the A-Coil. As your air conditioner runs, the refrigerant absorbs heat from the air passing over the coil, cooling the air before it circulates throughout the house.
• Your heat pump system can work in reverse to provide heat. In this scenario, the outdoor unit heats the refrigerant in the A-Coil, allowing it to heat the air passing over the A-Coil. The furnace’s blower fan then distributes the heated air.

Outdoor Condenser Unit Connection

• The outdoor condenser unit connects to the A-Coil inside the house via 2 refrigerant lines. The high-pressure line, or liquid line, carries refrigerant from the outdoor unit to the A-Coil. The low-pressure line, which is also called the suction line, carries refrigerant back to outdoor unit.
• The outdoor unit’s compressor pressurizes the refrigerant.
• When the system is cooling, the condenser coil of the outdoor unit releases heat to the outside air. When the system is heating, the condenser coil absorbs heat from the outside air.

Two-Stage Thermostat Connection

• The two-stage thermostat connects to the furnace and heat pump/air conditioning system. The term “two-stage” refers to the system being able to control two different levels of heating or cooling. The first stage is typically the heat pump or air conditioner, while the second stage is the furnace.
• After setting your desired temperature on the thermostat, the device sends a signal to the appropriate system to turn On or Off. If you’re cooling your home, the thermostat turns On the air conditioning for the first stage. If you’re heating your home, the thermostat activates the heat pump for the first stage. If either first stage can’t reach the desired temperature, the thermostat turns On the furnace for the second stage to supply additional heat to the home.
• In heating scenarios, the thermostat first turns On the heat pump if the outdoor weather is above a certain level. This occurs because heat pumps are more efficient in milder weather. If it’s too cold outside for the heat pump to efficiently work, certain thermostat types switch the entire heating function to the furnace instead.