Carbolite VMF/ASTM Series - Manual (Page 8)

SNF
8
MF31 – 3.06
6.0 F AULT A NALYSIS
A. Furnace Does Not Heat Up
1. The temperature
controller is OFF
 No power from the
supply
 Check the fuses in the supply
line
 There are no lights
glowing on the
controller
 The controller may be faulty or
not receiving a supply due to a
faulty switch or a wiring fault
2. The temperature
controller is ON
 The controller shows a
very high temperature
or a code such as S.br
 The thermocouple has broken
or has a wiring fault
 The controller shows a
low temperature
 The SSR could be failing to
switch on due to internal
failure, faulty logic wiring
form the controller, or faulty
controller
B. Furnace Overheats
1. Furnace only heats up
when the instrument
switch is ON
 The controller shows a
very high temperature
 The controller is faulty
 The controller shows a
low temperature
 The thermocouple may have
been shorted out or may have
been moved out of the furnace
 The thermocouple may be
mounted the wrong way round
 The controller may be faulty
2. Furnace heats up when
the instrument switch
is OFF
 The SSR has failed
“ON”
 Check for an accidental wiring
fault which could have
overloaded the SSR