Lochinvar 000 - 2, 495 Temperature Control Sensors, Boiler Application, Water Heater Application

Hydronic Heating Boilers and Domestic Water Heaters

OPERATION

Continued

Temperature Control Sensors

This is a two-stage temperature control that controls the burner ignition, pump, and alarm functions. This temperature controller can measure up to three different sensor inputs, depending upon how the unit is set up. They are as follows:

1.Inlet Water Temperature Sensor

2.Multi-Purpose Temperature Sensor

3.Outside Air Temperature Sensor

Inlet Water Temperature Sensor

This sensor measures the inlet water temperature coming into the unit.

Multi-Purpose Temperature Sensor

Depending upon how your unit is set up, this sensor can be used as a system sensor or a tank sensor.

Outdoor Air Temperature Sensor

This sensor is only available on boiler units with an outdoor air reset option. This allows you to tie boiler operation to the outdoor air temperature. As outside temperatures drop, the control will increase the temperature setting of the boiler. As outdoor temperatures rise, the control will decrease the temperature to the selected set point of the boiler. You can set the control to shut the boiler off when a desired outdoor air temperature level is reached.

Figure 37 - Outdoor Air Reset Chart Example

Boiler Application

Standard boiler units are shipped with two sensors; the inlet water temperature sensor and the multi-purpose temperature sensor. The multi-purpose sensor should be used as a system sensor. Boilers with the outdoor air reset option also have an outside air temperature sensor.

Water Heater Application

Water heater units are shipped with two sensors; the inlet water temperature sensor and the multi-purpose temperature sensor to be used as a tank sensor.

Placement of Sensors

Inlet Temperature Sensor

The inlet water temperature sensor is placed into the inlet bulbwell on the boiler. This sensor is installed by the factory in new units. Make sure to insert the sensor all the way into the bulbwell, leaving no air pocket between the front surface of the sensor and the back of the bulbwell. Air pockets are thermally non-conductive and will cause sensors to not read accurately.

System Sensor

This is used for boiler applications. This sensor will control the boiler operation based upon the water temperature within the building loop.

Tank Sensor

This is used in water heating applications. Place the sensor in the water storage tank to measure water temperature. For more information on mounting the sensor, see Remote Mounting of Sensors, page 33.

Outside Air Temperature Sensor

The outside air temperature sensor will only be used for boiler systems. The outside air sensor is optional. You must purchase the sensor from the appliance manufacturer. The sensor comes with a housing that helps protect the sensor from the elements. Mount the air sensor housing under the eve of the roof. Make sure the housing is out of direct sunlight. This will ensure that the sensor will accurately read the true outdoor temperature. For more information on mounting the sensor, see Remote Mounting of Sensors, page 33.

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