Lochinvar 497 - 2067 Temperature control sensors, Boiler application, Water heater application

Installation & Service Manual

5 Electrical connections

Temperature control sensors

(continued)

Boiler application

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

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.

Remote sensor for pump delay

This appliance is provided with a special thermostat sensor that MUST be field installed. The sensor is shipped loose in the I & O packet. This remote mounted sensor will be the primary water sensor which will inform the appliance's built- in thermostat control. Reading the water temperature at the remote location is required for proper operation of the pump delay option provided with this appliance.

For domestic water heating, the sensor must be installed into a bulbwell on the storage tank. For boiler and hydronic heating, the sensor must be installed in the system piping loop. If the appliance is controlled by a remote sequencer, the sensor must be routed back into the appliance and placed in a bulbwell on the inlet side of the heat exchanger.

The sensor must be connected to two wires provided on the side of the appliance with the water connections (FIG. 5-9). It will be necessary to add additional wire to reach from the appliance to the remote water source. Use twisted pair wire or minimum 18 gauge wire or larger. Reference Table 5C on page 42 for a chart regarding distance versus wire gauge.

Figure 5-9_Remote sensor for pump delay

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 installed by the factory in new units. The sensor is an immersion style and maintains direct contact with the water.

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 42.

Outdoor 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 42.

Figure 5-10_Outdoor air reset chart example

FIELD SUPPLIED WIRING

CONNECTION BOARD

SYSTEM/

TANK

SENSOR

REQUIRED IN ORDER FOR PUMP DELAY TO FUNCTION PROPERLY

	1	+	SYSTEM/TANK
	2	+	SENSOR
	3	+	B2 INTERMITTENT
4		+	B1	LIMITS
5		+	A2	CONTINUOUS
6		+	A1	LIMITS
7		+	2 NO HIGH FIRE
8		+	2 C	ENABLE
9		+	1 NO LOW FIRE
10		+	1 C	ENABLE

61

72

83

94

10 5

41