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
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
6.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 6. Refer to Table 8 for Trouble Shooting Guide.
Table 6: 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 | |
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 | |
output is turned off); check B1 wiring/voltage. | ||
|
The operating sequence for the L7224/L7248 is shown in Table 7.
Table 7: L7248/L7224 Controller Operating Sequence
Action | System Response |
Thermostat | Circulator starts when water temperature |
calls for heat. | is above Low Limit setting (if applicable). |
| Boiler temperature is checked. Burner |
| starts when water temperature is below |
| High Limit setting. |
Boiler | Burner is turned off. Burner restarts when |
exceeds the | the water temperature drops below the |
High Limit. | High Limit setting minus the Differential. |
Thermostat is | Circulator and burner turn off. |
satisfied. |
|
Error | If an error condition is detected, all outputs |
condition | except ZC are shut down. Burner is off. |
| Control continues to function and restarts |
| when error is corrected. |
| During the error check sequence, the |
| system checks for drift in the sensor and |
| corrosion in the connections. |
Error | EnviraCOM communication is not |
condition 6. | available. |
Error | The control has reset the High Limit, Low |
condition 7. | Limit and Differential setting to a default |
| setting and will continue to run at those |
| settings. |
| Performance of the system will be |
| degraded. |
Error | If the error condition is detected, all |
condition 8. | outputs except ZC are shut down. Burner |
| is off. Control continues to function and |
| restarts when all three user keys have |
| been pressed longer than 60 seconds. |
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