A.O. Smith GB/GW-650, GB/GW-750, GB/GW-200 warranty Display Current Mode, Display Total Cycle Count

To change or view the current programmed post-circulating time:

1.Press the SELECT push-button on the display board until the LED display reads OPt (Options).

2.To enter into the options mode, press the ENTER/RESET push- button.

3.The display will illustrate Circ. Enter this mode by pressing the ENTER/RESET push-button.

4.The display will now illustrate the current post circulate time. Press the ADJUST push-button to select the desired post cir- culate time (45, 90, 180, On).

5.When you have selected the desired post circulate time mode, press the ENTER/RESET push-button once, this enters the selected post circulate time into controller memory.

6.The display will automatically resort to illustrating the outlet tem- perature.

Display Current Mode

In this mode, the Display Board will illustrate the current functional step in the appliance operational sequence. For example, if the appliance is performing Ignitor Warm-up, the display will illustrate IGnt. To enter into this mode, perform the following steps:

1.Press the SELECT push-button on the display board until the LED display reads OPt (Options).

2.To enter into the options mode, press the ENTER/RESET push- button.

3.The display will illustrate Circ. Press the SELECT push-but- ton until the display illustrates StEP. Enter this mode by press- ing the ENTER/RESET push-button.

4.The display will illustrate the current appliance operating step.

5.The display will automatically resort to illustrating the outlet tem- perature. To keep the display in the Display Step Mode, press ENTER/RESET twice in step 3.

Display Message	Appliance Mode
IdLe	Idle state
NoSn	Wait for No Sensor Inputs
CrSn	Wait for Circulate Sense
Circ	Circulate Pump is ON
PrSn	Wait for Blower Pressure
	Sense
PreP	Pre-Purge state
IGnt	Ignitor Warm-up
rEdn	Turn ON redundant Gas
	Valve relay
IAct	Turn ON Gas Valves
StAb	Turn OFF Ignitor and wait for
	Flame Sense Stabilization
HEAt	Heat Mode
PoPC	Post Purge and Post Circu-
	late
Po C	Post Circulate

Display Total Cycle Count

The Main Control Board counts the number of cycles the appliance has operated. In the Main Control Board, a cycle is counted every time the gas valve is energized. To access this number, perform the following procedure:

1.Press the SELECT push-button on the display board until the LED display reads OPt (Options).

2.To enter into the options mode, press the ENTER/RESET push- button.

3.The display will illustrate Circ. Press the SELECT push-but- ton until the display illustrates Count. Enter this mode by press- ing the ENTER/RESET push-button.

4.The display will now illustrate the current number of cycles the appliance has cycled through.

5.The display will automatically resort to illustrating the outlet tem- perature.

TANK PROBE INSTALLATION PROCEDURE

A tank probe is supplied with each hot water supply boiler. When installed on a tank, the inlet water temperature on the Dia-Scan II will default to the tank temperature. See figures 2 and 3 to add the tank jumper to the control board so that the tank probe is active.

A tank probe is NOT supplied with the hydronic heating boilers (GB's). Therefore, a loop or operating thermostat must be provided. This field-supplied operating thermostat should be wired to the BROWN wires at the junction box. The jumper at location J33 on the control board must NOT be on. Refer to figures 2 and 3 for the location of this jumper.

Tank Probe Set-Point Adjustment

When tank probe is installed in a storage water tank, and the tank probe is used with the WHC1502 system, the controller will monitor and control the temperature of the water at the tank probe location. Setting the tank probe set-point temperature is accomplished through the Display Board control panel. The standard program- mable temperature range for the indirect water tank is 110°F to 190°F. The switching differential of the probe is fixed at 5°F.

Tank Probe Temperature Set-point Adjustment Procedure

The user can easily change the tank probe water temperature set- point at any time by using the following procedure:

1.Press the SELECT push-button on the display board until both the Set-Pt LED (LED 15, see figure 1) and Inlet Wa- ter Temperature LED (LED 12, see figure 1) are illumi- nated.

NOTE 3: When a tank probe is connected to the board at location CN10, the Inlet Water Temperature LED defaults to Tank Water Temperature.

2.The LED display will show the current tank set-point tem- perature.

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

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

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

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

If the ADJUST push-button is held down long enough, the set-point will reach 110°F, the minimum value (or 190°F, the maximum value) and stop. At this point, if the desired set-point is not obtained, re- lease the ADJUST push-button and depress it again. The set-point value will now restart at 110°F (190°F) and once again increase (decrease) in value for as long as the ADJUST push-button is pressed.

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