Lennox International Inc 11K71 instruction

[fT _ _ Technical

HEAT PUMP KITS

AND ACCESSORIES

@1995 Lennox Industries Inc.

	503,214M
Dallas, Texas	1/95

_LJ_ Publications

Litho U.S.A.

REPLACEMENT DEFROST

CONTROL BOARD

INSTALLATION INSTRUCTIONS FOR REPLACEMENT DEFROST CONTROL BOARD KIT

(11K71) USED WITH HP29, 10HPB, 12HPB SERIES UNITS

Package 1 of I contains:

1- Replacement defrost control board

The replacement defrost control board for the HP29 and 10HPB series units is part number 68J84. This board replaces the original control board with part number 68J24. Unit wiring to the defrost board is the same. More options are provided in the replacement board such as ambient thermistor and service light connections.

The replacement board has the same basic functions as the original board along with the following functions:

five minute compressor anti-short delay; pressure switch safety lockout circuit; and

field connection for ambient thermistor and service light connections.

WARNING

CAUTION

The provided board is a direct replacement. Remove wires from original board and remove board from

control box area. Secure replacement board stand-offs into mounting holes. Wire as shown on unit wiring diagram.

The unit's defrost system includes two components; a defrost thermostat (see unit installation instructions) and a defrost control. The following section describes defrost control functions.

The defrost control board has the combined functions

of a time/temperature defrost control, defrost relay, time delay, diagnostic LEDs and field connection terminal strip.

The control provides automatic switching from normal heating operation to defrost mode and back. During compressor cycle (call for defrost), the control accumulates compressor run times at 30, 60 or 90 minute field adjustable intervals. If the defrost thermostat remains closed when the accumulated compressor run time ends, the defrost relay is energized and defrost begins.

Defrost Control Timing Pins

Each timing pin selection provides a different

accumulated compressor run period during one thermostat run cycle. This time period must occur before a defrost cycle is initiated. The defrost interval can be adjusted to 30, 60 or 90 minutes. See figure 1. The defrost period is a maximum of 14 minutes and cannot be adjusted. If no timing is selected, the control defaults to 90 minutes. The factory and recommended setting is 60 minutes.

A TEST option is provided for troubleshooting. When the jumper is placed across the TEST pins, the timing of all functions is reduced by a factor of 128. For example, a 90 minute interval during TEST is 42 seconds and the 14 minute defrost is reduced to 6.5 seconds.

The TEST mode may be started at anytime. If the jumper is in the TEST position at power-up or for longer than five minutes, the control will ignore the TEST selection and will default to a 90 minute interval.

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11K71 specifications

Lennox International Inc. is renowned for its innovation and excellence in the heating, ventilation, and air conditioning (HVAC) industry. One of the standout products in its range is the Lennox 11K71, a high-efficiency heat pump that showcases the company's commitment to energy savings, environmental sustainability, and advanced technology.

The Lennox 11K71 is designed for both residential and commercial applications, offering superior performance and reliability. A key feature of this unit is its SEER (Seasonal Energy Efficiency Ratio) rating, which often exceeds 16. This high rating demonstrates the unit’s ability to efficiently cool spaces, making it an ideal choice for consumers looking to reduce their energy consumption and lower utility bills.

One of the main technologies integrated into the Lennox 11K71 is variable speed compression. This allows the unit to adjust its cooling capacity based on the current demands of the environment, leading to enhanced comfort levels and further energy savings. The unit operates at lower speeds for longer periods, dramatically reducing energy consumption while maintaining a consistent temperature.

Additionally, the Lennox 11K71 features a smart thermostat compatibility option, allowing users to connect the system to their smart home networks. This connectivity facilitates remote monitoring and control through mobile devices, providing convenience for users while optimizing energy use.

Another significant characteristic of the Lennox 11K71 is its whisper-quiet operation. The design incorporates advanced sound dampening technology, ensuring that the unit operates quietly, a feature particularly beneficial for residential locations. This emphasis on noise reduction makes the system suitable for multi-family units or homes in noise-sensitive areas.

Durability is also a hallmark of the Lennox 11K71. Constructed with high-quality materials, the unit is built to withstand various weather conditions, ensuring longevity and reliable service. Its streamlined design not only enhances aesthetics but also promotes efficient airflow, further improving the unit's overall performance.

In conclusion, the Lennox 11K71 exemplifies state-of-the-art HVAC technology with its high efficiency, variable speed compression, smart thermostat integration, quiet operation, and robust construction. This heat pump is an excellent investment for anyone seeking an effective and reliable heating and cooling solution. With a focus on energy efficiency and user convenience, the Lennox 11K71 stands out as a leading option in modern HVAC systems.