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Action
Thermostat calls for heat.
Boiler temperature exceeds the High Limit. Burner is turned off. Burner restarts when the water temperature
Thermostat is satisfied.
Boiler temperature drops below the Low
Limit setting minus the differential (if
applicable).
Error condition
1-5.
Error condition 6.
Error condition 7.
Error condition 8.
Error condition 9*.
Error condition 10*.
Error condition 11*.
* Error condition only available when the Outdoor Reset Module is installed.
Table 6. L7224/L7248 Controller Operating Sequence.
Circulator starts when water temperature is above Low Limit
setting (if applicable) or above the Thermal Purge Temperature
Limit (tPL) if Thermal Purge is enabled. Boiler temperature is
checked. Burner starts when water temperature is below High
Limit setting minus the differential or at or below the Thermal
Purge Temperature Limit (tPL) for cold start boilers if the Thermal
Purge Temperature Limit is enabled. If tPL is enabled, the burner
may also start if the boiler temperature is cooling at 10 ºF or
greater per minute or the Thermal Purge Time Delay (tPt) has
expired.
If Anti Short-Cycle Time is enabled, the burner does not start until
the set Anti Short-Cycle Time between cycles expires after the
previous call for heat was satisfied.
drops below the High Limit setting minus the Differential. If
Thermal Purge is enabled, the burner is turned on when either the
Thermal Purge Temperature Limit is reached, the Thermal Purge
Time Delay has expired or the boiler temperature cooling rate
exceeds 10 ºF/minute.
Circulator and burner turn off.
Burner is turned on, Circulator is turned off. Burner stops when the
water temperature exceeds the Low Limit setting. Power to Zc is
removed.
If an error condition is detected, all outputs 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.
EnviraCOM communication is not available.
The control has reset the High Limit, Low Limit and Differential
setting to a default setting and will continue to run at those
settings.
Performance of the system will be degraded.
If the error condition is detected, all 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.
System continues to run with no outdoor reset functionality
System continues to run with outdoor reset parameters enabled as
programmed. Error cleared automatically.
System continues to run with boiler temp set to High Limit.
L7224A,C; L7248A,C,L OIL AND ELECTRIC BOILER
System Response
9
68-0281—18
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