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QUANTUM NXT DI HEATER OPERATION / MAINTENANCE MANUAL
2.4.a Low Pressure Switch Interlock
The pressure switch will disengage power if system inlet water pressure
drops below 15 psig (103 kPa). The heater will come back online if the
pressure recovers within a 10 second time period. After the 10 second
delay, an alarm will sound indicating low pressure. Once pressure is
restored, press the reset button and press ‘on’ to begin heating again.
The delay prevents nuisance trips due to transient conditions in the DI
water supply while still protecting the heater. However, erratic process
temperature control may result if heater power is disengaged during the
pressure transient.
2.4.b Liquid Level Sensor Interlock
The Liquid Level Sensors will disengage power to the system if the
heater modules are not full of water or if boiling in the heating module
occurs. The heater will reengage if fluid is present within a 10 second
time period. After the 10 second delay, an alarm will sound indicating
low liquid level. Once the water level is restored, press the reset
button and press ‘on’ to begin heating again. The delay prevents
nuisance trips due to transient conditions in the DI water supply while
still protecting the heater during startup. It is critical that these sensors
operate properly. Do not tamper with the sensors. Damage to the
system can result if the sensors are altered or overridden.
2.4.c Element Over-Temperature Protection
The temperature limit controller monitors a thermocouple attached to
each heater element as well as thermocouples attached to the back
panel and the heatsink(s). In the event that the element, back panel or
heat sink(s) temperature exceeds the normal operating temperature, the
system will immediately disengage power and alarm. If this occurs,
check element continuity before continuing normal operation. After
correcting any faults, press the reset button then the ‘on’ button to
begin heating again. See Section 7.1.
2.4.d Leak Sensor
When triggered, the Leak Sensor will immediately disable the heater
power and isolate the inlet water supply. Fix any leaks and dry the leak
sensor and leak tray prior to turning power on to the system. After
correcting any leaks, press the reset button then the ‘on’ button to
begin heating again.
2.4.e Over-pressure Relief
The over-pressure relief valve (“Relief Drain”) is self-resetting and
connected in-line with the cold DI inlet port to provide a mechanical
safeguard against possible over-pressure damage. Do not operate the
heater above 414 kPa (60 psig).
If the over-pressure relief device opens, pressure will relieve out the over
pressure drain and the low-pressure sensor may alarm.
