Installation & Service Manual

5 Electrical connections

Setpoint

The Set Point knob specifies the target water temperature in degrees, Fahrenheit. After the water temperature reaches the set point, the temperature control shuts off the burners.

Differential

The Differential specifies the number of degrees below the set point that the control will allow the water temperature to drop before it brings the unit back on again.

High-fire offset

The temperature control operates a two-stage firing system. The two stages are High-Fire and Low-Fire. High-Fire operates all burners while Low-Fire operates approximately one-half of the burners.

The High-Fire knob specifies the number of degrees below set point that the High-Fire stage shuts down. At that point, the unit will continue to operate at the Low-Fire stage until the set point is reached.

The High-Fire offset knob has settings between 0°F and 20°F. If set at 0°F, the High-Fire offset is disabled and the unit will operate at the High-Fire stage until the set point is reached and the temperature control shuts the unit off.

When the High-Fire offset knob is set to 0 or 1, the unit will light at Low Fire and operate for approximately 10 seconds before the High-Fire stage actuates. When set to 2 or above, the unit will operate at Low Fire for 2 minutes before the High Fire stage can actuate.

Figure 5-8_Optional outdoor reset control

OUTDOOR

OUTDOOR

AIR

AIR

SHUTDOWN

SENSOR

SHUTDOWN

 

OUTDOOR

RATIO

AIR

 

MAX

 

40

 

Outdoor reset option

For boilers ordered with the Outdoor Air Reset option, there is an additional control (see FIG. 5-8). There are three setting knobs for Shutdown, Outdoor Air Max., and Ratio. There is also a switch to turn the outdoor air sensor On or Off. An O.A. Sensor is also included.

Shutdown

The Shutdown knob specifies the outdoor air shutdown temperature at which the control would prevent the unit from operating. This feature can be enabled/disabled with the O.A. Shutdown switch.

Outdoor air max (O. A. Max)

The O. A. Max knob allows a reset up to the maximum outdoor air temperature specified by this knob setting. When the outdoor air temperature is above the specified setting, the unit will not function in the O.A. Reset Mode, but will continue to run at the selected set point temperature.

Note that the set point knob will now indicate the “minimum” boiler temperature. Target temperature is determined by the ratio and outdoor air temperature below the O.A. Max setting.

Ratio

The Ratio knob allows the control over the reset ratio to be used during Outdoor Air Reset. The allowable ratios are as low as 0.5:1 or as high as 1.5:1.

Selecting the 0.5:1 ratio will increase the set point 0.5°F for every 1.0°F drop in outdoor air temperature up to the maximum set point temperature.

Selecting the 1.5:1 ratio will increase the set point 1.5°F for every 1.0°F drop in outdoor air temperature up to the maximum set point temperature (see page 39).

See FIG. 5-10 for an outdoor air reset chart example.

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Lochinvar 497 - 2067 service manual Outdoor reset option
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497 - 2067 specifications

Lochinvar 497 - 2067 is a highly efficient and versatile condensing boiler that is designed to meet the diverse heating needs of residential and commercial applications. Known for its impressive performance and advanced technology, the Lochinvar 497 - 2067 has garnered a reputation as a reliable choice among heating professionals.

One of the standout features of the Lochinvar 497 - 2067 is its impressive thermal efficiency. The boiler boasts an efficiency rating of up to 95% AFUE (Annual Fuel Utilization Efficiency), allowing users to significantly reduce their energy costs while minimizing environmental impact. This efficiency is facilitated by its innovative condensing technology, which captures and reuses heat from exhaust gases for optimal performance.

The Lochinvar 497 - 2067 is equipped with a robust stainless steel heat exchanger designed to handle high temperatures and ensure long-lasting performance. The heat exchanger’s design maximizes heat transfer, while its corrosion-resistant properties guarantee durability over time. This contributes to the boiler's overall longevity and serviceability, reducing the need for frequent replacements.

Control is another critical feature of the Lochinvar 497 - 2067. The boiler comes with an advanced control system that enables easy management of system operations. Users can take advantage of features such as outdoor reset control, which adjusts the temperature of the boiler based on external weather conditions, enhancing system efficiency and comfort.

In terms of safety, the Lochinvar 497 - 2067 incorporates several cutting-edge safety features, including a flame detection system and multiple safety shut-off devices. These safeguards help to ensure the safe operation of the boiler, providing peace of mind to users and heating professionals alike.

Another important characteristic is the compact design of the Lochinvar 497 - 2067, which allows for flexible installation in various settings, including tight spaces. Its lightweight structure further simplifies the installation process, making it a practical choice for contractors.

In summary, the Lochinvar 497 - 2067 is an exceptional high-efficiency condensing boiler that combines advanced technology, durability, and ease of use. With its impressive thermal efficiency, superior heat exchanger design, advanced control systems, and enhanced safety measures, it stands out as a top choice for those seeking reliable heating solutions. This boiler not only meets but exceeds modern demands for energy efficiency and performance, solidifying its position in the market.
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