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== Operation ==
== Operation ==
Details to follow.


== Adjustments ==
== Adjustments ==
Details to follow.


== Maintenance ==
== Maintenance ==
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First, always ensure that the breaker and GFCI are not tripped, and that the power switch on the side of the unit is turned on.
First, always ensure that the breaker and GFCI are not tripped, and that the power switch on the side of the unit is turned on.
If the boiler does not fire in response to a call for heat, the issue is likely related to an interlock or the ignition system.  Verify that the low water sensor is reset; it can be tripped by air infiltration during filter back-washing.  Ensure that the pump is operating.  Verify that the covers are securely fastened; a loose cover leaks air and may not close the air pressure switches.  Finally, check for the presence of spark and/or pilot light.  This is visible via a small window on the lower-left of the unit.
If the boiler does not fire in response to a call for heat, the issue is likely related to an interlock or the ignition system.  Verify that the low water sensor is reset; it can be tripped by air infiltration when the pump is stopped.  Ensure that the pump is operating.  Verify that the covers are securely fastened; a loose cover leaks air and may not close the air pressure switches.  Finally, check for the presence of spark and/or pilot light.  This is visible via a small window on the lower-left of the unit.
 
The automation system may provide some additional insight regarding a boiler fault state via the [[Pool_Systems_Automation#Display_and_Keypad|PLC Display]].  In the topics below, additional faults and possible remedies are explored.
The flame sensor unit is a consumable item and may need to be replaced at a regular interval (every two years?).  If the pilot valve (PV) is open, but the main valve (MV) never opens, it is likely that adequate flame is not being detected.  This can be verified by measuring the microamp current output of the flame sensor and should be done by a qualified technician.
=== Low Air Pressure ===
 
The <b>Low Air Pressure</b> switch closes when the positive air pressure differential formed in the combustion chamber meets a minimum threshold.  Assuming the blower is operating, insufficient air pressure may be the result of:
 
* Excessive air leakage.  Tighten enclosure bolts and an adequate seal is present.  Sometimes, pushing on the boiler's combustion chamber enclosure panel may be enough to force marginal pressure over the threshold.
* Improper airflow adjustments.  Consult a qualified technician; blower airflow may need to be adjusted.
* A failed air pressure switch, or an electrical issue.  Repair may be necessary.
 
This fault may be identified by the [[Pool Systems Automation#Boiler Status|boiler status]] indicated the LCD on the automation system PLC.
 
=== Natural Gas Odor ===
 
A natural gas odor may be observed when the flame sense module (FSM) has opened the pilot valve, but no spark is present.  The pilot gas is flowing but has not ignited.  In this case, it is likely that the ignition transformer has failed.
 
Turn off the boiler and contact a qualified technician.


=== Low Temperature Fault ===
=== Low Temperature Fault ===


A boiler controller [[Pool_Boiler_Temperature_Controller#Low_Temperature_Fault|Low Temperature Fault]] is often caused by one of the following:
A boiler controller [[Pool Boiler Temperature Controller#Low Temperature Fault|Low Temperature Fault]] is often caused by one of the following:


* The recirculation valve is not in the optimal position and should be [[#Recirculation Valve|adjusted]].  Reasons the valve may need adjustment include:
* The recirculation valve is not in the optimal position and should be [[#Recirculation Valve|adjusted]].  Reasons the valve may need adjustment include:
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=== High Temperature Fault ===
=== High Temperature Fault ===
== Known Issues ==
The following issues are known as of September 2021.
=== Low-Water Cut-Off ===
The implementation of the low-water cut-off (LWCO) could potentially be improved.  In the present design (as found in 2020, where the control transformer is cut off):
* The pump could theoretically continue to operate following a low-water trip per time delay relay TD4.
* The loss of control power prevents detection of a low-water condition by the PLC; the PLC does not even "see" a demand for heat when the cut-off is tripped.
Options to consider:
* The T7CS5D-24 relay in the LWCO is rated for a 12 A load at 120 VAC.  Move T1 (C1 pin #4) from terminal 1 to the output of the LWCO.  This would serve to immediately disconnect the pump upon low-water trip.
* Reconnect the control transformer to terminal 3 (per RBI drawings).  Disconnect the LWCO relay contacts and remove the factory jumper from H to C (to confirm).  Insert the LWCO contact between terminals 17 and 18 in the boiler (remove jumper "F" per RBI drawings).
=== Power Switch ===
The power switch does not disconnect the control transformer.  This is fixed by reconnecting the control transformer to terminal 3 (as suggested above).


== 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: Main Gas Valve On ===


Description pending.
The main gas valve (also referred to as the "main valve" or MV) turns on (becomes active) when the flame sense module (FSM) confirms the presence of the pilot flame.
 
Once this has occurred:
 
# Relay R8 is energized to disable the spark generator transformer.
# The MAIN GAS indicator on the boiler is illuminated.
# The automation system relay CR2113 is energized, which activates [[Pool Systems Automation#Digital Inputs|PLC input X13]].
# The relay in the [[Pool Temperature Controller|pool temperature controller]] is energized, which provides confirmation that a request for heat has been satisfied.
# The boiler temperature controller [[Pool Boiler Temperature Controller#Main Valve Active|main valve active]] input (relay) is energized.


==== Stage E ====
=== Stage E: Stage 2 Active ===


Description pending.
Description pending.


=== Control Interlocks ===
== Summary of Control Interlocks ==


The list below includes interlocks with electrical interfaces only and is intended to align with the CSD-1.  This table is for reference only; the CSD-1 should always be considered the master.
The list below includes interlocks with electrical interfaces only and is intended to align with the CSD-1.  This table is for reference only; the CSD-1 should always be considered the master.
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* Relay coil taps were added to add monitoring of operating conditions by an external PLC.  These connections are documented in the pool systems automation [[:File:FFSC-001_Pg_40_-_Boiler_Auxiliary.png|Boiler Auxiliary]] drawing.
* Relay coil taps were added to add monitoring of operating conditions by an external PLC.  These connections are documented in the pool systems automation [[:File:FFSC-001_Pg_40_-_Boiler_Auxiliary.png|Boiler Auxiliary]] drawing.
* Re-routing of some electrical in new liquid-tight conduit.
* Re-routing of some electrical in new liquid-tight conduit.
== Known Issues ==
The following issues are known as of September 2021.
=== Low-Water Cut-Off ===
The implementation of the low-water cut-off (LWCO) could potentially be improved.  In the present design (as found in 2020, where the control transformer is cut off):
* The pump could theoretically continue to operate following a low-water trip per time delay relay TD4.
* The loss of control power prevents detection of a low-water condition by the PLC; the PLC does not even "see" a demand for heat when the cut-off is tripped.
Options to consider:
* The T7CS5D-24 relay in the LWCO is rated for a 12 A load at 120 VAC.  Move T1 (C1 pin #4) from terminal 1 to the output of the LWCO.  This would serve to immediately disconnect the pump upon low-water trip.
* Reconnect the control transformer to terminal 3 (per RBI drawings).  Disconnect the LWCO relay contacts and remove the factory jumper from H to C (to confirm).  Insert the LWCO contact between terminals 17 and 18 in the boiler (remove jumper "F" per RBI drawings).
=== Power Switch ===
The power switch does not disconnect the control transformer.  This is fixed by reconnecting the control transformer to terminal 3 (as suggested above).
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