Carbolite EZS Series - Manual (Page 21)

E range
MF65-1.01 21 21
5.7 Fuse Replacement
Fuses are marked on the circuit diagram (section 7) with type codes, e.g. F1, F2. A list of the
correct fuses is given in section8 page 23.
If a fuse has failed, it is advisable for an electrician to check the internal circuits.
Replace any failed fuses with the correct type. For safety reasons do not fit larger capacity fuses.
The fuses are near the cable entry point, and access is by removal of the back panel of the base or
control box.
6 FAULT ANALYSIS
A. Furnace Does Not Heat Up
1. The HEAT light
is ON
 The heating
element has failed
 Check also that the SSR is working
correctly
2. The HEAT light
is OFF 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 heater switch may be faulty or need
adjustment
 The contactor (if fitted) may be faulty
 The SSR could be failing to switch on due
to internal failure, faulty logic wiring from
the controller, or faulty controller
There are no lights
glowing on the
controller
 Check the supply fuses and any fuses in the
furnace control compartment
 The controller may be faulty or not
receiving a supply due to a faulty switch or
a wiring fault
B. Furnace
Overheats
1. The HEAT light
goes OFF with
the instrument
switch
 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 heating chamber
 The thermocouple may be mounted the
wrong way round
 The controller may be faulty
2. The HEAT light
does not go off
with the
instrument
switch
 The SSR has failed
“ON”
 Check for in correct wiring or other
fault which could have overloaded the
SSR