Thermal Solutions APEX APX425C Installation, Operating And Service Instructions page 82

10
Operation
(continued)
Table 10-8: Hydronic System
Parameter and
Description
Boiler Pump
System Pump
Primary Loop Piped
DHW Pump
Table 10-9: Comfort Settings
Parameter and Description
Minimum Outdoor Temperature
Maximum Outdoor Temperature
Low Water Temperature
Minimum Boiler Water Temperature
Table 10-10: Response Speed
Parameter and Description
Central Heat Response Speed
Central Heat Low Fire Hold Time
Domestic Response Speed
Domestic Low Fire Hold Time
Sequencer Response Speed
Table 10-11: Sequence of Operation
Status
Standby
Safe Startup
Drive Purge
Prepurge
Drive Lightoff
Preignition Test
Preignition
Direct Ignition
Running
Postpurge
82
Factory Setting
Any Demand
Any Demand
Central Heat, Optional Priority, Fresh Air Damper
IWH
Factory/Setting (°F)
Factory Setting
120 seconds
10 seconds
Boiler is not firing. Appropriate circulators are on if Priority is not Standby. With a
central heat demand, sequence proceeds from Standby when supply temperature
drops below Setpoint minus Difference Below.
Flame circuit is tested.
Blower is driven to purge speed.
Combustion chamber is purged for 10 s after reaching purge speed.
Blower is driven to lightoff speed.
Control conducts safety relay test.
Spark is energized and it is confirmed that no flame is present.
Spark and gas valve are energized.
After flame is proven, sequence continues with run stabilization and, when selected,
low fire hold time and slow start ramp. Once field adjustable low fire hold time
and ramp rate is completed, normal boiler operation begins with modulation rate
dependent on temperature and setpoint selections.
When the call for heat ends, gas valve is closed. Combustion chamber is purged for
10 s after blower reaches postpurge speed.
APEX Installation, Operating, & Service Instructions
Range/Choices
Never, Any Demand
Central Heat, OFF DHW Demand
Header Sensor Demand/
Combustion air Damper
Never
Any Demand
Central Heat, No Priority
Never
Primary Loop Piped IWH
Boiler Piped IWH, Fresh Air Damper
0
70
110
130
Range / Choices
3 1 to 5
0 to 1800 seconds
3 1 to 5
0 to 1800 seconds
3 0 to 5
Description
Range/Choices (°F)
-50 to 32
35 to 100
70 to 180
50 to 185
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