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1 Service (continued) | Building Management System (BMS) | |
Cascade | ||
Boiler address
The boiler designated as the Leader needs to be programmed with address 0. All the Member boilers require addresses from 1 to 7, and the addresses must be different for each Member. The addresses can be in any order, regardless of the order in which the units are wired together. The outdoor air (if used), system supply sensor, and system return sensor must be connected to the Leader boiler. The default address is 1.
Maximum Cascade setpoint
When the system supply sensor is connected, or the system supply temperature is provided through ModBus, this parameter determines the setpoint used by the individual boilers in a Cascade. When a boiler is commanded to fire by the Leader boiler, it will attempt to achieve this temperature at its outlet. The Leader boiler will limit the modulation of the last boiler to fire in order to hold the temperature at the system supply sensor to the user setpoint. If any of the boiler outlet temperatures reach the max. cascade setpoint, the boiler will then modulate down on its own in order to keep its outlet temperature within the max. cascade setpoint. Therefore, this parameter can be used to limit the outlet temperatures of all the boilers in a Cascade. Note that this parameter does not apply when the boiler is heating an indirect DHW tank. The temperature range for this parameter is 32°F (0°C) - 261°F (127°C). The default max. cascade setpoint is 185°F (85°C).
Cascade offset (boiler only)
This parameter determines how much the temperature must go above setpoint before the lead boiler will turn off. The temperature range for this parameter is 0°F (0°C) - 54°F (30°C). The default value is 9.9°F (5°C).
Cascade differential (boiler only)
This parameter determines how much the temperature must go below the turn off temperature (Setpoint + Offset) before the lead boiler turns on. The temperature range for this parameter is 0°F (0°C) - 54°F (30°C). The default value is 19.8°F (11°C).
BMS type
When the unit or cascade is controlled by the
Voltage at minimum
This setting determines the voltage at which the external signal begins to increase either the modulation or the setpoint. Below this voltage, the modulation or setpoint will be at their minimum values. The range for this parameter is 0V - (Voltage at Maximum parameter - 0.1V). The default value is 2V.
Voltage at maximum
This setting determines the voltage at which the external signal forces either the modulation or the setpoint to their maximum value. This parameter, along with the previous parameter, determines how much the modulation or setpoint changes as the BMS input voltage changes. The modulation or setpoint will change in proportion to the change in voltage between the minimum and maximum voltage settings. The range for this parameter is (Voltage at Minimum parameter + 0.1V) - 10V. The default setting is 10V.
Minimum power
This setting determines the modulation of the unit or cascade when the BMS input voltage is at or below the Voltage at Minimum setting. This parameter is active only when the BMS type is set to Power. The range for this parameter is 0 - Maximum Power parameter. The default value is 20%.
Maximum power
This setting determines the modulation of the unit or cascade when the BMS input voltage is at or above the Voltage at Maximum setting. This parameter is only active when the BMS type is set to Power. The range for this parameter is Minimum Power parameter - 100%. The default value is 100%.
Minimum setpoint
This setting determines the setpoint used by the unit or cascade when the BMS voltage is at or below the Voltage at Minimum setting. This parameter is only active when the BMS type is set to Setpoint. The temperature range for this parameter is 32°F (0°C) - 230°F (110°C) (boilers), or 32°F (0°C) to 190°F (87°C) (water heaters). The default value is 70°F (21°C).
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