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Interlocks prevent the boiler from operating when the water level is too low, sufficient water flow is not present or the air pressure differential (as generated by the blower motors) is insufficient.  Redundant over-temperature lock-outs (including those added by FFSC maintenance) prevent operation in the event that the temperature rises beyond a threshold.
Interlocks prevent the boiler from operating when the water level is too low, sufficient water flow is not present or the air pressure differential (as generated by the blower motors) is insufficient.  Redundant over-temperature lock-outs (including those added by FFSC maintenance) prevent operation in the event that the temperature rises beyond a threshold.
== Maintenance ==
Regular inspections are mandated by the state and the insurance company.  These inspections occur every three years.  Prior to the official inspection, a '''Steam/Hot Water ASME CSD-1''' form must be completed by a qualified technician.  This form contains details about the boiler (identified by the state license and serial numbers), identifying key controls, their set-points and operation test results.  Any issues found during the technician's inspection must be remedied before the document becomes acceptable as proof of compliance per Rule 27 of the State of Michigan Boiler Code.
Two copies of the CSD-1 should be kept by FFSC.  One placed in a room near the boiler, another in a central filing location.
== Adjustments ==
=== Recirculation Valve ===
Adjustments to the recirculation valve require extreme care, especially when the main pump is operating.  The butterfly valve has a tendency to pull itself closed rapidly if the operator is not careful.  Such a rapid change in flow and pressure may cause significant damage to the system.
When adjusting the recirculation valve, use the following precautions:
* Ideally, turn off the main pump before adjusting.
* If the main pump cannot be stopped, use two hands and extreme care in moving the valve position.  Ensure the valve is locked into a notch before releasing the lever.
* Adjust the position by no more than 1-2 notches in the open or closed direction.  Observe changing in the operating parameters (i.e. boiler manifold temperature) before making additional adjustments.
== Troubleshooting ==
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.
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 Temperature Fault ===
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:
** A significant change in pool temperature.  Early season operation (where the pool is significantly lower than 80 °F) will require the valve to be closed further.
** A significant change in operating flow rate.
* The recirculation pump may not be operating.  Verify that the pump is operating properly.
=== High Temperature Fault ===
== 2021 Electrical Overhaul ==
[[File:RBI Boiler Controls May 2020.jpg|thumbnail|The pre-overhaul boiler control wiring in May 2020.]]
In 2021, a significant effort was made to overhaul the wiring in the boiler.  Observed issues included:
* A literal tangle of wires, many removed from the wire tracks and/or excessively long, arranged without an apparent effort towards neatness.  It's really not clear how much of the wiring was installed at the factory this way, or how much of it was worsened by numerous service efforts throughout the years.
* Burned insulation on a few wires, presumably from a known overheating event that occurred shortly after installation.
* A wiring mistake (not consistent with the schematic).
* Use of aluminum MC conduit (outside of the unit) in a corrosive environment.
* A great deal of dirt accumulation throughout.
Debugging and servicing the unit were very difficult. 
[[File:RBI Boiler Controls May 2021.jpg|thumbnail|The overhauled boiler control wiring in May 2021.]]
The overhaul also resulted in a few additional changes:
* The Johnson Controls C450CCN-3 was moved to an external location for enhanced monitoring by a human operator.
* 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.
== 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 ==
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Description pending.
Description pending.


== Control Interlocks ==
=== 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.
Line 129: Line 209:
|12 µA
|12 µA
|}
|}
== Maintenance ==
Regular inspections are mandated by the state and the insurance company.  These inspections occur every three years.  Prior to the official inspection, a '''Steam/Hot Water ASME CSD-1''' form must be completed by a qualified technician.  This form contains details about the boiler (identified by the state license and serial numbers), identifying key controls, their set-points and operation test results.  Any issues found during the technician's inspection must be remedied before the document becomes acceptable as proof of compliance per Rule 27 of the State of Michigan Boiler Code.
Two copies of the CSD-1 should be kept by FFSC.  One placed in a room near the boiler, another in a central filing location.
== Adjustments ==
=== Recirculation Valve ===
Adjustments to the recirculation valve require extreme care, especially when the main pump is operating.  The butterfly valve has a tendency to pull itself closed rapidly if the operator is not careful.  Such a rapid change in flow and pressure may cause significant damage to the system.
When adjusting the recirculation valve, use the following precautions:
* Ideally, turn off the main pump before adjusting.
* If the main pump cannot be stopped, use two hands and extreme care in moving the valve position.  Ensure the valve is locked into a notch before releasing the lever.
* Adjust the position by no more than 1-2 notches in the open or closed direction.  Observe changing in the operating parameters (i.e. boiler manifold temperature) before making additional adjustments.
== Troubleshooting ==
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.
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 Temperature Fault ===
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:
** A significant change in pool temperature.  Early season operation (where the pool is significantly lower than 80 °F) will require the valve to be closed further.
** A significant change in operating flow rate.
* The recirculation pump may not be operating.  Verify that the pump is operating properly.
=== High Temperature Fault ===
== 2021 Electrical Overhaul ==
[[File:RBI Boiler Controls May 2020.jpg|thumbnail|The pre-overhaul boiler control wiring in May 2020.]]
In 2021, a significant effort was made to overhaul the wiring in the boiler.  Observed issues included:
* A literal tangle of wires, many removed from the wire tracks and/or excessively long, arranged without an apparent effort towards neatness.  It's really not clear how much of the wiring was installed at the factory this way, or how much of it was worsened by numerous service efforts throughout the years.
* Burned insulation on a few wires, presumably from a known overheating event that occurred shortly after installation.
* A wiring mistake (not consistent with the schematic).
* Use of aluminum MC conduit (outside of the unit) in a corrosive environment.
* A great deal of dirt accumulation throughout.
Debugging and servicing the unit were very difficult. 
[[File:RBI Boiler Controls May 2021.jpg|thumbnail|The overhauled boiler control wiring in May 2021.]]
The overhaul also resulted in a few additional changes:
* The Johnson Controls C450CCN-3 was moved to an external location for enhanced monitoring by a human operator.
* 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.
== 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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