Pool Boiler: Difference between revisions
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=== Stage A: Demand for Heat === | === Stage A: Demand for Heat === | ||
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 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 | # 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 | # 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 | 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]]. | # The automation system relay CR2110 is energized, which activates [[Pool Systems Automation#Digital Inputs|PLC input X10]]. | ||
=== Stage B: Flow | === Stage B: Temperature and Water Flow OK === | ||
The | The temperature and water flow are deemed OK when: | ||
# The <b>High Temp</b> | # 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 <b>Water Flow</b> switch is | # 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 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. | |||
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. | |||
=== Stage D === | === Stage D === | ||