Alpine Installation, Operating, and Service Instructions

103448-02 - 6/13 95
X. Operation E. Boiler Sequence Of Operation (continued)
Status Screen Display Description
Supply
140 F
140 F
Rate
0%
Status:
Setpoint
Boiler 1
>
<
Priority:
Standby
i
Standby
Priority:
Standby
Status:
Standby
(burner Off, circulator(s) Off)
Boiler is not ring and there is no call for heat, priority equals standby. The boiler
is ready to respond to a call for heat.
Supply
140 F
140 F
Rate
0%
Status:
Setpoint
Boiler 1
>
<
Priority:
Central Heat
i
Standby
Priority:
Central Heat
Status:
Standby
(burner Off, circulator(s) On)
Boiler is not ring. There is a Central Heat call for heat and the Supply temperature
is greater than setpoint minus the “Diff Below”.
Supply
132 F
140 F
Rate
98%
Status:
Setpoint
Boiler 1
>
<
Priority:
Central Heat
i
Prepurge 10
Priority:
Central Heat
Status:
Prepurge
When supply temperature drops burner demand continues with following Status
shown:
Safe Startup: Flame circuit is tested.
Drive purge: The blower is driven to the fan purge speed.
Prepurge: After the blower reaches the fan purge speed setting the 10
second combustion chamber purge is conducted.
Supply
132 F
140 F
Rate
89%
Status:
Setpoint
Boiler 1
>
<
Priority:
Central Heat
i
Direct Ignition
Priority:
Central Heat
Status:
Direct
ignition
After purge time is complete the following Status is shown:
Drive light-off: The blower is driven to light-off rate.
Pre-Ignition Test: After the blower reaches light-off rate a safety relay test is
conducted.
Pre-ignition: Spark is energized and it is conrmed that no ame is present
Direct Ignition: Spark and Main fuel valve are energized.
Supply
132 F
140 F
Rate
100%
Status:
Setpoint
Boiler 1
>
<
Priority:
Central Heat
i
Running
Priority:
Central Heat
Status:
Running
(burner On, circulator(s) On)
After ame is proven normal boiler operation begins. Modulation rate depending
on temperature and setpoint selections and modulating control action.
Supply
132 F
180 F
Rate
100%
Status:
Setpoint
Boiler 1
>
<
Priority:
Domestic Hot Water
i
Running
Priority:
Domestic
Hot Water
Status:
Running
If the Central Heat call for heat is active and a Domestic Hot Water (DHW) call for
heat received the DHW demand becomes the “priority” and the modulation rate,
setpoint, “Diff Above” and “Diff Below” are based on DHW settings.
Priority:
Standby
Status:
Post-purge
(burner Off, circulator(s) Off)
If there is no call for heat the main fuel valve is closed and the blower is driven
to the fan post-purge speed. After the blower reaches the fan post-purge speed
setting the 30 second combustion chamber purge is conducted.
Priority:
Standby
Status:
Standby
Delay
This state is entered when a delay is needed before allowing the burner control to
be available. For example, when Anti-Short Cycle time is selected Standby delay
is entered after the Central Heat call for heat ends. Select “Help” button from the
“Home Screen” to determine the cause of the Standby Delay.
Priority:
Standby
Status:
Lockout
A lockout Status is entered to prevent the boiler from running due to a detected
problem. Select “Help” button from the “Home Screen” to determine the cause of
the Lockout. The last 10 Lockouts are recorded in the Lockout History.
E. Boiler Sequence of Operation
1. Normal Operation
Table 31: Boiler Sequence of Operation