Figure 15. Ignition Control Board Jumper Settings

switch "D" on the Central Control Board is placed in the "ON" position, it will show the temperature at the tank probe. (See Figure 14.) The push buttons on the Display Board allow the user to program and view several system parameters described in the following text. The Display Board is connected to the Central Control Board through a 6 conductor cable assembly with modular plug terminations. In addition, an 8 conductor modular jack on the Display Board allows for connecting a remote display board.

When power is applied to the Control System, the Display Board will initially run through a self-diagnostic test, and then display the inlet temperature. To display a specific setting or temperature, press the SELECT push-button until the appropriate LED is illuminated (see Figure 16). After 5 seconds, the Display Board will automatically revert to displaying the Inlet temperature. Press- ing the ENTER/RESET push-button will hold the display in the indicated mode until the SELECT push-button is pressed.

With the display board, the user can make adjustments to many of the appliance’s control features. This includes the following:

Options/Features Setting Procedures

Set Appliance Stage Temperature Set-point Value

Set Appliance Stage Switching Differential Value

Select Appliance Post-Circulate Time

Check Appliance Cycle Count

View Last Error Encountered by Control

Control the water temperature in a storage tank

Green Status Lights

Green LEDs indicate when a given stage has sensed flame and is in the heating state. They also are used to indicate when the Set-Point differential for a given stage is being viewed or adjusted. (See Figure 16.)

STAGE 1: Stage One in Operation

STAGE 2: Stage Two in Operation

STAGE 3: Stage Three in Operation

STAGE 4: Stage Four in Operation

Red Fault Lights

The Red LEDs are illuminated to show faults and help in trouble shooting. There are three faults (High Gas Fail, LWCO and Power Vent Fail) listed as "Optional" which are only functional when the particular "Optional" equipment is included with the boiler. The red stage LEDs indicate on which stage a given fault has occurred. (See Figure 16.)

Blocked Flue: Blockage in Flue

Probe Fail: One of the controlling Probes has failed

Insufficient Air: Not enough Air to Close Switch

Circulate Fail: Flow Switch Not Closed

Gas Valve Fail: Relay for Gas Valve in Incorrect State

High Limit: High Limit has been Exceeded

Flame Fail: No Flame Sensed upon Ignition

Igniter Fail: Igniter did not reach Minimum Amperage

Low Gas Fail: Gas Pressure too low to Close Switch

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A.O. Smith 2100, 200, 201, 2500, 1850, 1300, 1500 Options/Features Setting Procedures, Green Status Lights, Red Fault Lights