A.O. Smith 1300, 200 Procedure for Setting Tank Probe Temperature, Application Hydronic Heating

1.Press the SELECT push-button on the display board until both the Set-Pt LED and Inlet Water Temperature LED (see Figure 16) are illuminated.

2.The LED display will show the current set-point temperature.

3.Press and hold the ADJUST push-button. The displayed temperature will either increase or decrease. To alternate between increasing or decreasing the temperature, release then press and hold the ADJUST push-button.

4.When the desired set-point temperature is reached, release the ADJUST push-button.

5.Press the ENTER/RESET push-button once, this enters the selected set-point temperature into controller memory.

6.The appliance will now control the temperature to the desired set-point value.

7.For setting the stage differentials, see the section labeled Procedure for Setting Stage Differential.

NOTE: The boiler must complete a full cycle in order for the new setting to take effect. If the unit is turned off prior to a complete cycle the setting will be lost and the previous setting will remain in effect.

24 VAC System Controller (Optional)

A 24 VAC thermostat/aquastat can be implemented as a system controller on Genesis units. The connection for such devices is located in the 24 VAC junction box at the rear of the unit. A 24 VAC thermostat/aquastat can only be used as an "On/Off" switch for the unit. The actual controlling of the staging will be through either the inlet or tank probe. To use a 24 VAC system controller, dip switch "E" on the CCB must be switched to the "on" position. See Figure 14.

Tank Probe (Optional)

In addition to the Inlet and Outlet/ECO Probes, units can be optionally equipped with a tank Probe. The connection for the tank probe is located in the 24 VAC junction box at the rear of the unit. The tank Probe can be configured to control the staging of the unit. See Tank Probe Installation section on page 17 for additional information.

Procedure for Setting Tank Probe Temperature

If you have a GW hot water supply boiler, and have installed the tank probe, below are the instructions on how to adjust the water temperature set-point.

1.Press the SELECT push-button on the display board until both the Set-Pt LED and Inlet Water Temperature LED (see Figure 16) are illuminated.

2.The LED display will show the current set-point temperature.

3.Press and hold the ADJUST push-button. The displayed temperature will either increase or decrease. To alternate between increasing or decreasing the temperature, release then press and hold the ADJUST push-button.

4.When the desired set-point temperature is reached, release the ADJUST push-button.

5.Press the ENTER/RESET push-button once, this enters the selected set-point temperature into controller memory.

6.The appliance will now control the temperature to the desired set-point value.

7.For setting the stage differentials, see the section labeled Procedure for Setting Stage Differential.

Procedure for Setting Stage Differential

Once the system control and set-point temperature has been entered, the switching differentials for the staging of the unit must

be established. To facilitate proper operation and maximize appliance performance, each stage has a programmable operating switching differential or “hysteresis” about the set point. This means a call for heat for a particular stage will become active when the water temperature measured at the controlling temperature sensing probe drops to the set-point value minus the switching differential value. It is necessary to set three set-point differential values for three stage units and four for four stage. The burner will remain on until the water temperature measured at controlling probe reaches the stage set-point value. The switching differential value is fully programmable from 0° F to 20°F (0°C to 11°C) using the push-button(s) located on the Display Board.

To change or view the current programmed switching differential:

1.Press the SELECT push-button on the display board until both the Set-Pt Diff. and green Stage One LED (see Figure 16) are illuminated.

2.The LED display will show the current differential for stage one.

3.Press and hold the ADJUST push-button. The displayed value will either increase or decrease. To alternate between increasing or decreasing the differential, release then press and hold the ADJUST push-button.

4.When the desired Set-Pt differential is reached, release the ADJUST push-button.

5.Press the ENTER/RESET push-button once, this enters the selected set-point deferential into controller memory. To view the Set-Pt minus the Set-Pt differential, press and hold the "ENTER" push-button. This will be the "turn-on" temperature for Stage One and the "turn-off" temperature for Stage Two.

6.Repeat steps 2 through 5 for the rest of the stages.

7.The appliance will now control temperature utilizing the desired differentials.

Example:

Application: Hydronic Heating

Desired System Temperature: 185°F (85°C)

Stage Differentials: 5°F (3°C) per Stage.

Note: The user must first choose which probe is to control the staging of the unit. The controlling probe will be either the inlet or tank probe. (If the tank probe is used to regulate loop temperature in hydronic applications (GB Models), make sure it is located on the return side of the closed loop.) Use Dip Switch "D" on the Central Control Board to make this selection. See Figure 14.

Set the stage differentials using the procedure described in the Procedure for Setting Stage Differential section of the document. Setting the control as described in the above example (5°F differentials for each stage) will give the following stage set-points.

Stage One

Off Temperature: 185°F (85°C)

On Temperature: 180°F (82°C)

Stage Two

Off Temperature: 180°F (82°C)

On Temperature: 175°F (79°C)

Stage Three

Off Temperature: 175°F (79°C)

On Temperature: 170°F (77°C)

Stage Four

Off Temperature: 170°F (77°C)

On Temperature: 165°F (74°C)

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