World Leaders in Ultra-Pure Heating
Revision 10
www.heateflex.com
01/17/13
405 E. Santa Clara St.
Arcadia, CA 91006-7218
Tel: (626) 599-8566 Fax: (626) 599-9567
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5.1.2 Temperature Switches
There is one temperature switch on the unit mounted in the exhaust line to the vessel‟s pressure
relief valve for sensing pressure relief venting conditions. It is adjusted to approximately 20°F
higher than its normal operating temperature when the unit is in service. It is adjusted by
turning its adjustment screw towards colder temperatures until it trips while the unit is in
operation then adjusting it to the 20°F higher setting. The factory default setting is 155°F.
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5.1.3 Pressure Transducer
There is one pressure transducer on the unit mounted in the PVDF piping on the left side of the
unit. It is adjusted to trip if the D.I. line pressure falls below the specified Low Process
Pressure alarm set point. The pressure transducer is integrated with a visual pressure gauge
that can be used to monitor the D.I. water supply line pressure and to check against the value
displayed on the touch screen monitor.
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5.1.4 Flow Sensor
The D.I. water flow rate is measured by a shedding-vortex flow meter mounted in the inlet
PVDF piping to the unit. It is used as an input to the temperature control section of the PLC
and the indicated flow rate can be observed on the System Status and Recalibration screens. If
the flow meter is recalibrated, it is necessary to also perform a Look-Up Table recalibration as
described in Section 3.2.3 of this manual.
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5.2 Process Exchanger Mechanicals
The process PFA heat exchanger is designed for many years of service. If the PFA heat
exchanger specifications and guidelines (specifically operating pressure and temperatures) are
followed there should not be any problems with the exchanger itself. Nevertheless there are
three possible conditions, which could eventually present themselves. First, a failure of the
tubing itself; second, a leak in the stainless steel pass-through fittings or in the PVDF flare
fittings where the individual tubes join the pipe manifolds on the top of the unit., and third, a
failure of the mixing valves. The next sections will detail the procedures for servicing these
problems.
