Slant/Fin EM-10 Installation - Manual (Page 8)

BOILER OUTLET MAXIMUM
The BOIL OUT MAX setting determines the highest water
temperature allowed at the boiler outlet sensor. The boiler
stages are immediately shut off once the water temperature
exceeds the BOIL OUT MAX setting at the boiler
outlet sensor location.
BOILER PUMP OPERATION
The boiler pump contact operates when:
• A heat demand is present and parallel piping (Mode 1,
3, 4, 6) is used. Parallel piping requires the boiler pump
to operate even while the boiler is off in order to provide
heat to the system.
• While the boiler is on and primary / secondary piping
(Mode 2, 5, 7) is used. Primary / secondary piping
reduces standby losses by isolating the boiler from the
system while the boiler is off.
• After the boiler shuts off the boiler pump remains on to
purge heat from the boiler to the system.
BOILER PUMP PURGE ( DLY)
After the boiler is shut off, the control continues to operate
the boiler pump for a period of time. The length of time that
the boiler pump continues to run is based on the Pump
DLY setting. Once the boiler turns off, the control keeps
the boiler pump running for the time selected. This setting
allows purging of any excess heat out of the boiler after the
boiler is shut off. This also helps to prevent the water in the
boiler from flashing into steam after the boiler is shut off.
When Pump DLY is set to OFF, there is no purging. When
Pump DLY is set to ON, the pump runs continuously. When
on is selected and the control is configured for outdoor reset,
the pump continues to run even during Warm Weather Shut
PUMP EXERCISING
If the boiler pump has not operated at least once every 70
hours, the control turns on the output for 10 seconds. This
minimizes the possibility of the pump seizing during a long
period of inactivity.
ALERT
The control closes the alert contact whenever an error
message is present.
A setpoint is a fixed water temperature target that the
boiler is to maintain at the operation sensor once a demand
is present. The boiler maintains the boiler target by
operating the stages using proportional or PID logic
together with the boiler differential.
Modes 4 to 7 and Setpoint Demand (Dem 2)
A setpoint demand is required whenever heat is required
for the secondary heating load such as an indirect domestic
hot water tank. A setpoint demand is generated when a
voltage between 24 and 120 V (ac) is applied across the
CD (common demand) and the Set D (setpoint demand).
Once voltage is applied, the control turns on the Dem 2
segment in the display and control operates the boiler stages
to maintain the BOIL TARGET at the boiler outlet sensor
(Mode 4, 6) or the boiler supply sensor (Mode 5, 7).
8 EM-10-40 Operation and Instruction Manual
Setpoint Operation
Setpoint Operation
+
1/2 Differential
Setpoint Target
- 1/2 Differential