BMC and
OUTDOOR CUTOFF TEMPERATURE |
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Adjustable Off, from 20ºF/ to70ºC - 100ºF, On | Default: 60ºF/ 16ºC |
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| Button: MENU/Set Point/Outdoor Cutoff | in Set Point | 65 F |
| Button: MENU/Set Point/Offset/Outdoor Cutoff | in Reset | [] |
•If the outdoor sensor is installed, the Outdoor Cutoff screen will automatically appear
after the temperature Set Point has been selected. | BACK | SAVE |
•When the outdoor temperature falls to the adjustable Outdoor Cutoff temperature, the BMC will control and modulate boilers to hold the calculated temperature.
•When the outdoor temperature rises to the Outdoor Cutoff plus a 2°F differential, the BMC will turn all boilers off. The System relay will remain energized for the
•The Outdoor Cutoff can be set from 20°F to 100°F. In addition, the Setting can be set to ON or OFF. In the ON position, the System Relay will run regardless of the Outdoor temperature (OD) and the burner stages will be active to hold the calculated water temperature. (Note: The lowest water temperature the BMC will circulate is 70°F. If the Outdoor Cutoff is turned ON and the Season is set to Winter, the BMC will circulate at least 70°F water even in the hottest of weather.) In the OFF position, the system pump will always be off and all burner stages will be off.
OFFSET | Default: 0Fº/0Cº | OFFSET | |
Adjustable from 50Fº/28Cº to |
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Button: MENU/Set Point/Offset | in Reset only |
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• The Offset setting lets you adjust the starting points of the Reset Ratio curves. This | [] |
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means that, regardless of the Outdoor temperature (OD), or the Reset Ratio that has |
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been selected, when the Offset setting is changed, that change is directly added to or | BACK | SAVE | |
subtracted from the calculated temperature. For example, if the Set Point temperature |
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was 130°F and the Offset was changed from 0° to 10° (an increase of 10°), then the Set |
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Point temperature would increase to 140°F |
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•The Offset setting does not change the ratio selection. For instance, with 1.00 (OD):1.00 (SYS) Reset Ratio, the System water temperature (SYS) will always increase one degree for each degree change in the Outdoor temperature (OD). What the Offset does is add or subtract a constant temperature value. (See Understanding Operation Concept on page 5)
•If required: Adjust the Water Offset in mild weather. If the ambient building temperatures are too warm in the mild weather, decrease the Water Offset. If the ambient building temperatures are too cold in the mild weather, increase the Water Offset. The rule of thumb for baseboard radiation is to change the Offset 4°F for every 1°F you wish to change the building temperatures.
In radiant heat applications, change the Offset 1°F or 2°F for every 1°F you wish to change the building temperature.
MINIMUM
WATER
TEMP
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MINIMUM WATER TEMP
Adjustable from 70ºF/21ºC to 180ºF/82ºC | Default: 140ºF/ 60ºC | 70 F | |
Button: MENU/Set Point/Offset/Outdoor Cutoff/Minimum Water Temp | in Reset only | [] | |
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•The Minimum Water Temperature must be set to the boiler manufacturer’s specification.
The BMC will calculate the Set Point based on the Outdoor temperature (OD), the Reset | BACK | SAVE |
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Ratio, and the Offset value. The BMC will control all boilers modulation to |
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hold either the Set Point temperature, or the Minimum Water Temperature, whichever is higher. |
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•The Minimum Water Temperature must be at least 20°F lower than the Maximum Temperature (See next setting).
MAXIMUM WATER TEMP
Adjustable 90ºF/21ºC - 240ºF/116ºC | Default: 200ºF/93ºC |
Button: MENU/Set Point/Offset/..../Maximum Water Temperature | in Reset only |
•This is the highest temperature heating water the BMC will circulate through the heating system. It is available in Reset mode only.
•When using a radiation system, it should be set according to the tubing or floor manufacturer’s specification.
•The Maximum Temperature must be at least 20°F higher than the Minimum Temperature (See previous setting).
MAXIMUM
WATER
TEMP
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| 240 F |
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