Lochinvar 45, CP-5M-4/08, 000 - 500 High-Fire Offset, Boiler Application, Water Heater Application

Set Point

The Set Point knob specifies the target outlet 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 at full rate while Low-Fire operates the burners at approximately one-half rate.

The High-Fire Offset 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 the High-Fire stage until the set point is reached and the temperature control shuts the unit off.

No matter what the High-Fire Offset knob is set to, the unit will light at Low Fire and operate for approximately 10 to 120 seconds before the High-Fire stage actuates.

Boiler Application

Standard boiler units are shipped with one sensor, the inlet water temperature sensor. An optional sensor can be purchased and installed for use as a remote 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.

Temperature Control Sensors

This is a two-stage temperature control that controls the burner ignition and pump 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.

The inlet water temperature sensor is placed into the inlet bulbwell on the boiler. This sensor is installed by the factory in new units.

Multi-Purpose Temperature Sensor

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

for water heater applications. Connect this sensor to the two blue wires in the upper left-hand corner of the control panel.

Outdoor Air Temperature Sensor

The outside air temperature sensor will only be used for boiler systems. The outside air sensor is optional. This sensor 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.

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 outdoors, 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. Connect the outdoor air temperature sensor to the terminal block on the outdoor air reset board. For more information on wiring the sensor, see Wiring of Remote Sensors, this page.

Installation of Remote Sensors

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 read inaccurately.

System Sensor

The system sensor is used for boiler applications. Install the sensor in the system supply to the building.

Tank Sensor

The tank sensor is used in water heating applications. Install the sensor in a water storage tank to measure water temperature. For more information on wiring the sensor, see Wiring of Remote Sensors below.

Wiring of Remote Sensors

To wire remote sensors, follow the guidelines below. Take care to correctly wire sensors to the unit. Erratic temperature readings can be caused by poor wiring practices. Twist the wires between the unit and the remote sensor. Turn wires at least three or four turns per linear foot of wiring. This provides protection against some types of electrical interferences.

1.Do not route temperature sensor wiring with building power wiring.

2.Do not locate temperature sensor wiring next to control contactors.

3.Do not locate temperature sensor wiring near electric motors.

4.Do not locate temperature sensor wiring near welding equipment.

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