Blower Control Board (A54)

!WARNING

Electric shock hazard. Can cause injury or death. Before attempting to perform any service or maintenance, turn the electrical power to unit OFF at disconnect switch(es). Unit may have multiple power

15CHAX units are equipped with a variable speed motor that is capable of maintaining a specified CFM throughout the external static range. A particular CFM can be obtained by positioning jumpers (COOL, HEAT, and ADJUST) on the blower control board. The HEAT and COOL jumpers are labeled A, B, C and D. Each of the numbers corre- sponds with an air volume (CFM) setting. The ADJUST jumper is labeled Test, −, +, and Norm. The + and − pin set- tings are used to add or subtract a percentage of the CFM selected. The Test jumper is used to operate the motor in the test mode. See figure 8.

Factory settings for the blower speed jumpers are given in the wiring diagram in figure 7. Figure 8 shows the blower control board. Use tables 2, 3 and 4 to determine the cor- rect air volume for operation in heat and cool mode.

The CFM LED located on the blower control board flashes one time per 100 cfm to indicate selected blower speed. For example, if the unit is operating at 1000 CFM, CFM LED will flash 10 times. If the CFM is 1150, CFM LED will flash 11 full times plus one fast or half flash.

At times the light may appear to flicker or glow. This takes place when the control is communicating with the motor be- tween cycles. This is normal operation.

Read through the jumper settings section before adjusting the jumper to obtain the appropriate blower speed.

To change jumper positions, gently pull the jumper off the pins and place it on the desired set of pins. The following section outlines the different jumper selections available and conditions associated with each one. Refer to figure 8.

After the CFM for each application has been determined, the jumper settings must be adjusted to reflect those given in tables 2, 3 and 4. From the tables, determine which row most closely matches the desired CFM. Once a specific row has been chosen (+, NORMAL, or −), CFM volumes from other rows cannot be used. Below are descriptions of the jumper selections.

The variable speed motor slowly ramps up to and down from the selected air flow during both cooling and heating demand. This minimizes noise and eliminates the initial blast of air when the blower is initially energized.

ADJUST

The ADJUST pins allow the motor to run at normal speed, approximately 15 percent higher, or approximately 15 per- cent lower than normal speed. Tables 2, 3 and 4 give three rows (+, NORMAL, and −) with their respective CFM vol- umes. Notice that the normal adjustment setting for cool speed position D in table 2 is 900 CFM. The + adjustment setting for that position is 1035 CFM and for the − adjust- ment setting is 765 CFM. After the adjustment setting has been determined, choose the remaining speed settings from those offered in the table in that row.

The TEST pin is available to bypass the blower control and run the motor at approximately 70 percent to make sure that the motor is operational. This is used mainly in trouble- shooting. The G terminal must be energized for the motor to run.

BLOWER CONTROL BOARD (A54)

 

ADJUST

16−PIN PLUG

SELECTOR PINS

(BOARD TO MOTOR)

(Setting affects both

 

heating and cooling

 

modes)

DIAGNOSTIC

HEATING SPEED

LED

SELECTOR PINS

 

COOLING SPEED

 

SELECTOR PINS

Figure 8

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Lennox International Inc 15CHAX Series installation instructions Blower Control Board A54, Adjust
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15CHAX Series specifications

Lennox International Inc. is a leading provider of climate control products and systems, and their 15CHAX Series represents a significant advancement in residential heating and cooling technology. This series is designed with efficiency, comfort, and advanced features to cater to modern HVAC needs.

One of the standout features of the 15CHAX Series is its impressive Seasonal Energy Efficiency Ratio (SEER) rating. With ratings up to 15 SEER, the 15CHAX units offer substantial energy savings compared to older models. This level of efficiency not only reduces electricity costs but also minimizes the environmental impact, making it a preferred choice for eco-conscious consumers.

The 15CHAX Series is equipped with variable-speed technology, which allows for more precise temperature control and enhanced comfort. This technology enables the unit to adjust its cooling output in real time based on the home’s needs, providing more consistent temperatures and improved humidity control. As a result, homeowners experience a higher level of comfort without the fluctuations often associated with single-speed units.

One of the defining characteristics of the 15CHAX Series is its quiet operation. The units are designed with advanced noise reduction features, including sound-dampening technology and insulated cabinetry, ensuring a peaceful indoor environment. This makes the 15CHAX perfect for installation in homes where noise reduction is important.

Moreover, Lennox's 15CHAX Series incorporates advanced technology features such as the iComfort S30 Smart Thermostat, which offers smart climate control and can be integrated with home automation systems. This allows homeowners to control their heating and cooling remotely via smartphones or smart devices, providing unparalleled convenience and energy management.

Durability and reliability are also vital components of the 15CHAX Series. Built with high-quality materials and components, these units are designed to withstand varying weather conditions and have a robust warranty, assuring customers of their long-lasting performance.

Overall, the Lennox 15CHAX Series exemplifies innovation in HVAC technology with its energy efficiency, quiet operation, advanced control features, and reliable performance. This makes it an excellent choice for homeowners looking to enhance their comfort while being mindful of energy consumption and environmental impact.
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