White Rodgers Furnace 21D83M-843 Manual - Wiring Diagram & Operation Guide

OPERATION

If flame is detected, then lost, the 50A66-843 control will repeat the initial ignition sequence for a total of three "recycles". After three unsuccessful "recycle" attempts, the control will go into system lockout.

If flame is established for more than 10 seconds after igni- tion, the 50A66-843 controller will clear the ignition attempt (or retry) counter. If flame is lost after 10 seconds, it will restart the ignition sequence. This can occur a maximum of four times before system lockout.

A momentary loss of gas supply, flame blowout, or a shorted or open condition in the flame probe circuit will be sensed within 2 seconds. The gas valve will de-energize and the control will restart the ignition sequence.Recycles will begin and the burner will operate normally if the gas supply returns, or the fault condition is corrected, before the last ignition attempt. Otherwise, the control will go into system lockout.

If the control has gone into system lockout, it may be pos- sible to reset the control by a momentary power interrup- tion of ten seconds or longer.Refer to PRECAUTIONARY,

SYSTEM LOCKOUT, AND DIAGNOSTIC FEATURES.

COOL MODE

In a typical system, a call for cool is initiated by closing the thermostat contacts. This energizes the 50A66-843 control's cooling sequence.The compressor is energized and the delay-to-fan-on period begins. After the delay- to-fan-on periods ends, the circulator fan is energized at cool speed. The electronic air cleaner (optional) is also energized. After the thermostat is satisfied, the compres- sor is de-energized and the delay-to-fan-off period begins. After the delay-to-fan-off period ends, the circulator fan and electronic air cleaner (optional) are de-energized.

MANUAL FAN ON MODE

If the thermostat fan switch is moved to the ON position, the circulator fan (heat speed) and optional electronic air cleaner are energized. When the fan switch is returned to the AUTO position, the circulator fan and electronic air cleaner (optional) are de-energized.

SYSTEM LOCKOUT AND DIAGNOSTIC FEATURES

SYSTEM LOCKOUT FEATURES

When system lockout occurs, the gas valve is de-energized. The circulator blower is energized at heat speed for some faults, and if flame is sensed, the inducer blower is en- ergized. The diagnostic indicator light will flash or glow continuously to indicate system status. (System lockout will never override the precautionary features.)

To reset the control after system lockout, do one of the following:

1.Interrupt the call for heat at the thermostat for at least onesecond,butlessthan20seconds(ifflameissensed with the gas valve de-energized, interrupting the call for heat at the thermostat will not reset the control).

2.Interrupt the 24 VAC power at the control for at least ten seconds. You may also need to reset the flame rollout sensor switch.

3.After one hour in lockout, the control will automatically reset itself.

DIAGNOSTIC FEATURES

The 50A66-843 control continuously monitors its own operation and the operation of the system. If a failure oc- curs, the DS 1 (red) and DS 2 (green) LEDs will indicate a failure code as shown on next page.

21D83M-843 specifications

The White Rodgers 21D83M-843 is a versatile and reliable thermostat designed for both residential and light commercial use. With its advanced features and user-friendly interface, it continues to be a popular choice among homeowners and HVAC professionals alike.

One of the main features of the 21D83M-843 is its ability to provide precise temperature control. This thermostat utilizes an electronic sensor that allows for accurate monitoring and adjustment of indoor climate, ensuring comfort while optimizing energy efficiency. The device supports multi-stage heating and cooling systems, including conventional and heat pump configurations, making it adaptable to various HVAC systems.

The 21D83M-843 showcases a clear and easy-to-read display, providing users with essential information in real-time. The backlit screen ensures visibility, even in low-light conditions. Additionally, the intuitive user interface simplifies programming and operation, allowing users to set schedules and adjust settings with ease.

Programmable settings are a highlight of the 21D83M-843. Homeowners can enjoy the benefits of scheduling their heating and cooling systems to align with their daily routines, which leads to significant energy savings. The thermostat allows for multiple daily temperature changes, ensuring that the home environment remains comfortable while energy costs are minimized.

One of the standout technologies incorporated in the 21D83M-843 is its adaptive intelligent recovery feature. This innovative technology learns the home’s heating and cooling patterns, allowing the thermostat to anticipate the desired temperature and reach it at the right time. This not only enhances comfort but also further contributes to energy efficiency.

Another notable characteristic is the thermostat’s durability and compatibility with various HVAC systems. It is designed to work seamlessly with 24-volt heating and cooling systems, making it suitable for a wide range of applications. Its robust construction promises long-lasting performance, providing peace of mind to users.

In conclusion, the White Rodgers 21D83M-843 is an outstanding choice for those seeking a reliable, energy-efficient thermostat. With its precise temperature control, user-friendly interface, programmable features, and advanced technologies, it stands out in the crowded thermostat market. Whether for residential or light commercial use, the 21D83M-843 effectively meets the demands of modern heating and cooling needs while promoting comfort and efficiency.