Pool Boiler: Difference between revisions

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== Theory of Operation ==
== Theory of Operation ==
=== Operation Sequence ===


The operation sequence below is based upon the procedure described in the LCD Series manual, with adaptations per the installation wiring.
The operation sequence below is based upon the procedure described in the LCD Series manual, with adaptations per the installation wiring.


=== Stage 0: Water Level OK ===
==== Stage 0: Water Level OK ====


The low-water cut-out disconnects power from the 75 VA control transformer in the boiler.  This prevents boiler operation when a low water situation is encountered.
The low-water cut-out disconnects power from the 75 VA control transformer in the boiler.  This prevents boiler operation when a low water situation is encountered.


=== Stage A: Demand for Heat ===
==== Stage A: Demand for Heat ====


A demand for heat occurs when all of the following conditions are met:
A demand for heat occurs when all of the following conditions are met:
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# The automation system relay CR2110 is energized, which activates [[Pool Systems Automation#Digital Inputs|PLC input X10]].
# The automation system relay CR2110 is energized, which activates [[Pool Systems Automation#Digital Inputs|PLC input X10]].


=== Stage B: Temperature and Water Flow OK ===
==== Stage B: Temperature and Water Flow OK ====


The temperature and water flow are deemed OK when:
The temperature and water flow are deemed OK when:
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# The automation system relay CR2111 is energized, which activates [[Pool Systems Automation#Digital Inputs|PLC input X11]].
# The automation system relay CR2111 is energized, which activates [[Pool Systems Automation#Digital Inputs|PLC input X11]].


=== Stage C: Low Air Pressure OK ===
==== Stage C: Low Air Pressure OK ====


The low air pressure switch closes in response to sufficient positive pressure in the combustion chamber.
The low air pressure switch closes in response to sufficient positive pressure in the combustion chamber.
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NOTE: Flame fail/lockout is not considered here.  The present flame sense module (FSM), or "intermittent pilot ignition" module, does not include alarm contacts (UTEC 1003-638A).  The specified module, a UTEC 1003-61A is unavailable on the market at this time.  The alarm contacts are required to engage R1, the flame fail/lockout relay.  This is problematic, as it would allow the ignition transformer to spark indefinitely, eventually resulting in component failure.  As a work-around, the automation system provides a monitored lockout function via the <b>Boiler Disable</b> relay.
NOTE: Flame fail/lockout is not considered here.  The present flame sense module (FSM), or "intermittent pilot ignition" module, does not include alarm contacts (UTEC 1003-638A).  The specified module, a UTEC 1003-61A is unavailable on the market at this time.  The alarm contacts are required to engage R1, the flame fail/lockout relay.  This is problematic, as it would allow the ignition transformer to spark indefinitely, eventually resulting in component failure.  As a work-around, the automation system provides a monitored lockout function via the <b>Boiler Disable</b> relay.


=== Stage D ===
==== Stage D ====


Description pending.
Description pending.


=== Stage E ===
==== Stage E ====


Description pending.
Description pending.

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