Thermal Solutions APEX APX425C - 10 Operation (continued); Sequencer Slave Settings; Limit Settings Configuration

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APEX Installation, Operating, & Service Instructions APEX Installation, Operating, & Service Instructions
12. Sequencer Slave
Select to access the following parameters.
Parameter and Description Factory Setting Range / Choices
Boiler Address
Each boiler must be given a unique address. When Slave Selection Order is set to
Use Normal Order, the boiler address is used by the Sequence Master as the boiler
start order.
None 1 to 8
Slave Selection Order
First Boiler will always be first to start.
Normal Boiler start order follows boiler address number.
Last Boiler will always be last to start.
Normal
First
Normal
Last
13. Limits
Select to access the following parameters.
Parameter and Description Factory Setting Range / Choices
Stepped Modulation Start Offset
Reduces firing rate when supply, differential, or stack temperature is Stepped
Modulation Start Offset degrees below the high limit setting to help avoid lockouts.
For example, when the setting is 20°F, maximum modulation rate will begin to be
reduced when stack temperature is 20°F below the Stack High Limit and will be at
minimum modulation when stack temperature is 10°F below the limit.
Note: Feature is only active for supply temperature when Header Sensor is selected
as modulation sensor, when a boiler is a slave, or when a boiler is responding to a
remote demand (4-20mA or Modbus).
20°F
(-6.7°C)
(Stepped
Modulation
Recycle Offset
+6°F) to 30°F
Stepped Modulation Recycle Offset
Recycles boiler when supply, differential, or stack temperature is Stepped
Modulation Recycle Offset degrees below the high limit setting to help avoid
lockouts. For example, when the setting is 10°F, the boiler will recycle when
temperature is 10°F below the limit.
Note: Feature is only active for supply temperature when Header Sensor is selected
as modulation sensor, when a boiler is a slave, or when a boiler is responding to a
remote demand (4-20mA or Modbus).
10°F
(-12.2°C)
10°F to (Stepped
Modulation Start
Offset - 6 °F)
Preferred Supply High Limit
Adjustable high limit for supply temperature. Adjustable only up to control maximum
value.
Note: Included to allow installers and inspectors to test the limits.
210°F
(98.9°C)
60 to 210°F
(16 to 98.9°C)
Preferred Stack High Limit
Adjustable high limit for stack temperature. Adjustable only up to control maximum
value.
Note: Included to allow installers and inspectors to test the limits.
204°F
(95.6°C)
150 to 204°F
(65.6 to 95.6°C)
10 Operation (continued)