Slant/Fin EM-10 Installation - Manual (Page 7)

7 EM-10-40 Operation and Instruction Manual
Minimum Off Time (MIN OFF)
The minimum off time is the minimum amount of time that
a stage must be off before it is allowed to turn on. Once a
stage turns off, it cannot turn on until a minimum off time
elapses. The minimum off time is adjustable through the
MIN OFF setting in the Adjust menu.
BOILER DIFFERENTIAL (DIFF)
A heat source must be operated with a differential in order to
reduce short cycling. The boiler differential is divided around
the boiler target temperature. The first stage
contact will close once the water temperature at the
operating sensor is 1/2 of the differential setting below the
boiler target temperature, and will open once the water
temperature at the operating sensor is 1/2 of the
differential setting above the boiler target temperature.
Manual Differential
The differential can be manually set using the DIFF setting
in the Adjust menu.
Auto Differential
Auto differential is only available when using PID staging.
If the Auto Differential is selected, the control automatically
determines the best differential as the load changes,
thereby improving efficiency. During light loads, the
differential is increased to allow longer on and off times to
reduce the potential for short cycling. During large loads, the
differential is narrowed thereby improving comfort in heating
spaces by reducing temperature swing.
FIRE DELAY (Burner symbol DLY)
Does NOT apply to electric boiler operation.
The Fire Delay is the delay time that may occur between
the time that the control closes the Stage 1 contact and
when the burner fires. This delay is usually the result of a
burner pre-purge or other forms of time delay built into the
burner’s safety circuits.
BOILER TARGET TEMPERATURE (BOIL TARGET)
The boiler target temperature is determined from the
mode of operation and the type of demand applied. The
control displays the temperature that it is currently trying to
maintain at the operating sensor as BOIL TARGET in the
View menu. The operating sensor for modes 1, 3, 4 and
6 is the boiler outlet sensor, and the operating sensor for
modes 2, 5 and 7 is the boiler supply sensor. If the control
does not presently have a requirement for heat, it displays
“– – – ” in the LCD. There is no boiler target temperature
generated in Mode 8.
BOILER MINIMUM (BOIL MIN)
The BOIL MIN setting is the lowest water temperature that
the control is allowed to use as a boiler target temperature.
During mild conditions, if the control calculates a boiler
target temperature that is below the BOIL MIN setting, the
boiler target temperature is adjusted to at least the BOIL
MIN setting. During this condition, if the boiler is operating,
the MIN segment turns on in the LCD while the boiler
target temperature or boiler operating sensor temperature
is viewed. If the installed boiler is designed for condensing
or low temperature operation, set the BOIL MIN adjustment
to OFF.
BOILER MAXIMUM (BOIL MAX)
The BOIL MAX setting is the highest water temperature that
the control is allowed to use as a boiler target
temperature. If the control does target BOIL MAX, and the
temperature at the boiler outlet sensor is near the BOIL MAX
temperature, the MAX segment turns on in the LCD while
the boiler target, boiler inlet, boiler outlet or boiler supply
temperature is viewed.
Proportional Staging
A Minimum On Time
B Minimum Off Time C Interstage On Delay
D Interstage Off Delay
A B C D
Fixed Differential
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Des ired Temperature Desired Temperature
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Increasing Time
ON ON
OFF OFF
Automatic Differential
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Low
Heat
Load
ON ON
OFF OFF
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High
Heat
Load
ON ON
F F O F F O
Partial Outdoor Reset
Decreasing Outdoor Air Temperature
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B oil MAX Boil MAX
B oil MIN Boil MIN
WWS D WWSD