FULTON FT-0080C, Инструкция по установке, эксплуатации, обслуживанию и каталог запасных частей

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FT-C Vertical Electric Thermal Fluid Heater Manual 12 2013 ISSUE 1
Page 55
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3.9.8
OPERATING TEMPERATURE CONTROL
The Coil Design unit is a fired heat exchanger and the safe control and monitoring of the thermal
fluid temperature is of vital importance. The safe maximum temperature of the fluid must be
strictly adhered to.
a) The safe maximum temperature of the fluid must be strictly adhered to.
b) When consulting fluid manufacturer’s literature for the safe maximum fluid temperature, note
that the temperatures quoted are the actual limit to which any of the fluids may be subjected.
It is important to remember that in any fired heater there exists a “film” temperature which is
higher than the temperature of the bulk of the fluid.
c) Temperature controllers measure the bulk temperature and not the film temperature. This
must be taken into consideration when setting the temperature controls.
d) These approximate guidelines for temperature settings are not to override the system design
parameters.
e) These instructions should be used with information from the system designer. Manufacturer’s
literature on the temperature controller is provided in the last section of this manual.
f) Standard primary temperature control sensing point location for On/Off and Modulating
heaters is on the heater outlet.
g) When optional inlet location of the primary controls is specified. the following instructions
may still be used with some modification. For instance when primary controls are located on
the inlet, the dead band range will be much narrower than on heaters with outlet control. In
addition, temperature changes will not be as immediately apparent.
h) An indicating temperature controller is used to regulate the thermal fluid temperature.
Typically the indicating control is a thermocouple.
j) The thermocouple is directly immersed in the thermal fluid in the heater. The setpoint of the
controller is regulated by the keypad.
k) The operating temperature should be set at least 10°C lower than the high limit temperature.
3.9.9
HIGH LIMIT TEMPERATURE CONTROL
a) All units are fitted with high temperature limit controllers which monitor the fluid temperature
in the heater. This limit controller provides over temperature protection. A high temperature
limit switch acts as an over temperature safety device. If the high temperature limit shuts
down the unit, the manual reset button on the limit switch must be pressed.
b) The high temperature limit controller is factory set to 280°C.
c) Several consecutive lockouts caused by the high temperature limit controller indicate the
need for immediate installation review, beginning with fluid level in the expansion tank, firing
rate, and circulating pump performance.
The High Temperature Reset button will need to be pressed to re-activate the system once the
thermal fluid temperature has fallen below the ‘high limit’.
This must be set to the lowest of the following:
» Maximum operating temperature of the fluid.
» Maximum operating temperature of the equipment.
» 15°F (9°C) over maximum system operating temperature.