Burnham RSA manual Display Readout, Operation, LED Error Codes, High Limit Controller

Figure 22: L7248/L7224 Circuit Board Layout -

Horizontal Mount

Then, press the UP and/or DOWN buttons to move the set point to the desired value. After 60 seconds without any button inputs, the control will automatically return to the RUN mode.

Note that L7224 Aquastat Controller will display all four (4) above-listed adjustment features, but L7248 Aquastat Controller will not display Low Limit and Low Limit Differential adjustment features.

6.DISPLAY READOUT

In the RUN mode, the Aquastat will flash "bt"

(boiler temp) followed by the temperature (i.e., 220), followed by °F or °C.

To read boiler settings, press the I key to read the parameter of interest. For example, press I High Limit (HL) is displayed, followed by a three-digit number, i.e., 220, followed by °F or °C. Pressing the I button again (on L7224 models) will display the Low Limit (LL) followed by a three-digit number and the corresponding degree designator. See Display Readout, Figure 23.

After approximately 60 seconds without any key presses, the display will enter a dim display mode. To return to the bright display mode, simply press any key.

Figure 23: Display Readout Definitions

7.OPERATION

The L7224 model can be in any of four operational states - Normal, High Limit, Low Limit and Error. The controller moves back and forth from High Limit to Normal to Low Limit state as part of normal operation.

The L7248 model is restricted to three operational states - Normal, High Limit and Error. The controller moves back and forth from High Limit to Normal state as part of normal operation.

For both models, the controller will enter the Error state when there is an abnormal condition. The operating states are:

a.Normal: Boiler temperature went below the High Limit setting (minus the Differential) and has not exceeded the High Limit setting; or the boiler temperature went above the Low Limit setting and has not gone below the Low Limit setting (minus the Differential).

b.High Limit: Boiler temperature went above the High Limit setting and has not dropped below the High Limit setting (minus the Differential).

c.Low Limit: Boiler temperature went below the Low Limit setting (minus the Low Limit Differential) and has not gone above the Low Limit setting.

d.Error: The controller has detected an error condition (e.g., open sensor) and has shut down the burner output. The ZC output is energized. The controller continues to monitor the system and automatically restarts if the error condition clears. Refer to Table 4.

Table 4: LED Error Codes

Error	Cause / Action
Code
Err1	Sensor fault; check sensor.
Err2	ECOM fault; check EnviraCOM™ wiring.
Err3	Hardware fault; replace control.
Err4	B1 fault; check B1 wiring/voltage.
Err5	Low Line; check L1-L2, 110 Vac.
Err6	Fuse; check ECOM wires, replace fuse.
Err7	EEPROM, HL, LL, Hdf, Ldf; reset to default values.
	Restore desired settings.
Err8	Repeated B1 fault (voltage present at B1 when out-
	put is turned off); check B1 wiring/voltage.

The operating sequence for the L7224/L7248 is shown in Table 5. See Table 6 for Trouble Shooting Guide.

8.HIGH LIMIT CONTROLLER

The High Limit opens and turns off the burner when the water temperature reaches the setpoint. The High Limit automatically resets after the water temperature drops past the setpoint and through the

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