Pool Boiler: Difference between revisions
→Stage E: High Air Pressure and High Operator
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== Operation == | == Operation == | ||
Details to follow. | |||
== Adjustments == | |||
Details to follow. | |||
== 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. | |||
=== 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 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. | |||
=== 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 === | |||
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 === | |||
== Theory of Operation == | |||
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. | ||
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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 === | |||
A demand for heat occurs when all of the following conditions are met: | |||
# The boiler temperature controller [[Pool Boiler Temperature Controller#Low Operator|low operator]] relay contact is closed, indicating that no faults are active. | |||
# The measured temperature (via the [[Pool Temperature Controller|pool temperature controller]]) has dropped to the heat threshold, which closes the relay contact. | |||
# The normally-closed <b>Boiler Disable</b> relay contact (part of the pool automation system) is closed (relay not activated), permitting boiler operation (no fault observed). | |||
NOTE: These three interlocks align with the LOW OPERATOR temperature switch from #11 to #13, REMOTE OPERATOR OPTION function from #13 to #14 and ENABLE RELAY OPTION from #14 to #15 in RBI drawing 42-2112. Connections at terminals #13 and #14 are no longer made within the boiler housing. | |||
If all three interlocks are satisfied: | |||
# The automation system relay CR2110 is energized, which activates [[Pool Systems Automation#Digital Inputs|PLC input X10]]. | |||
=== Stage B: Temperature and Water Flow OK === | |||
The temperature and water flow are deemed OK when: | |||
# The | # The <b>High Temp</b> latching switch is not closed (in the Honeywell L4006E, with a reset pushbutton located on the front side of the boiler). This is a normally-closed switch; the switch is closed when the high-temperature latch is not set. | ||
# The | # The <b>Water Flow</b> switch is closed, indicating that sufficient flow in the loop is present. | ||
NOTE: These two interlocks align with the HIGH TEMP temperature switch from #15 to #17 and WATER FLOW switch from #18 to #21. JUMPER F is in place; the low-water cut-off interlock is located earlier in the chain. | |||
If the <b>High Temp</b> interlock is satisfied: | |||
# The | # The boiler time-delay relay TD4 (blower delay post-purge) is engaged, which immediately energizes contactor C1, turning on the boiler loop circulation pump. Activation of the pump should result in closure of the <b>Water Flow</b> switch. | ||
If both the <b>High Temp</b> and <b>Water Flow</b> interlocks are satisfied: | |||
# The boiler time-delay relay TD3 (pump delay post-purge) is engaged, which immediately energizes contactor C2, turning on the blower motors (low speed). | # The boiler time-delay relay TD3 (pump delay post-purge) is engaged, which immediately energizes contactor C2, turning on the blower motors (low speed). | ||
# 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 === | === Stage C: Low Air Pressure OK === | ||
The low air pressure switch closes in response to sufficient positive pressure in the combustion chamber. | |||
Once the <b>Low Air Pressure</b> interlock is satisfied: | |||
# The boiler time-delay relay TD1 (blower delay pre-purge) is engaged. | |||
NOTE: This interlock aligns with the LOW AIR PRESS switch from #22 to TD1 pin #1. | |||
Once the TD1 delay has elapsed: | |||
# The flame sense module (FSM) is powered, which opens the pilot gas valve. Relay R7 is engaged, which powers the spark generator transformer. | |||
# The automation system relay CR2112 is energized, which activates [[Pool Systems Automation#Digital Inputs|PLC input X12]]. | |||
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: Main Gas Valve On === | |||
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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|12 µA | |12 µA | ||
|} | |} | ||
== 2021 Electrical Overhaul == | == 2021 Electrical Overhaul == | ||
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== Known Issues == | == Known Issues == | ||
The following issues are known as of September 2021. | |||
=== Low-Water Cut-Off === | === Low-Water Cut-Off === | ||