Carbolite VMF/ASTM Series - Manual (Page 4)

SNF
4
MF31 – 3.06
3.0 O PERATION
The instructions for operating the temperature controller are given in a separate manual.
3.1 Operating Cycle
The furnace is fitted with an Instrument switch. The switch cuts off power to the control circuit.
Switch on the electrical supply.
Operate the instrument switch to activate the temperature controller. The controller becomes
illuminated and goes through a short test cycle.
Adjust the temperature controller – see separate manual supplied.
Overtemperature option only. If the overtemperature controller has not yet been set as required, set
it and activate it according to the instructions in the separate manual supplied.
The furnace starts to heat up according to the controller set point or program. The Heat light glows
steadily at first and then flashes as the furnace approaches the desired temperature or a program
setpoint.
Overtemperature option only. If the overtemperature trip operates then an indicator in the
overtemperature controller flashes, and the heating elements are isolated. Find and correct the
cause before resetting the overtemperature controller according the instructions supplied.
To turn the furnace off, set the Instrument switch to it’s off position; the controller display will go
blank. If the furnace is to be left off unattended, isolate it the electrical supply.
3.2 Notes on the Test
The furnace is intended for use with tests in accordance with BS1016: Part107.1:1991 and
ISO501:1981.
Before commencing the test, the furnace chamber lid should be opened and the temperature
allowed to stabilise for no longer than 2 minutes. The test should be conducted with the furnace lid
open. When the test is completed, close the lid to conserve energy and prolong element life.
3.3 Operator Safety
Ceramic materials used in furnace insulation can become conducting at high temperatures; there is
therefore a potential danger to the operator, as this furnace is designed to be used with the chamber
lid open.
To guard against this danger, the furnace is fitted with a 30mA earth leakage (residual current)
circuit breaker mounted in the back of the case. This trips out in the event of accidental contact
with the heating element or current leakage through the insulation.
The device may be reset after tripping out. From time to time, test it using the integral test button.