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5
Trouble-shooting
Revision 3
© Moffat Ltd, September 2009
E32SUBC OVEN and PROOFER
5.3.3 No heat / No temperature
control
Temperature probe faulty
To verify reading refer to 3.4.6
The temperature probe can be tested by measur-
ing it’s resistance.Probe must be disconnected for
testing.
Element control relay faulty
To test refer to 3.4.6
The element contactor is controlled by relay #2
Check red flag on relay top to see if relay is ener-
gised. If no flag present check voltage (24Vdc) to
control relay coil. If voltage present replace relay.
If relay is operating check continuity through re-
lay contacts. Replace if no continuity through
contacts
Electronic control faulty
If no voltage is present at relay coil and controller
is calling for heating on display replace controller.
Heating contactor faulty
With a program selected, check that the heating
contactor coil has voltage across the coil,
terminals A1 and A2. If not check element con-
tactor control relay (#2) and wiring.
If voltage is correct, check that contactor pulls in
and closes the contacts when power to
contactor coil is on. Correct operation will make
an audible noise when closing contacts and on
the front face of the contactor the
contact mechanism will visibly pull in. If not,
contactor is faulty—replace.
If contactor operates correctly, check for
continuity through the poles of the contactor
when closed. If no continuity through
connected poles then contacts are blown and
contactor requires replacing.
Figure 5.3.3b
Terminal 5
Terminal A2
Terminal 6
Terminal A1
Terminal 1
Terminal 2
Temperature Resistance (kΩ)
0°C (32°F) 288
37°C (99°F) 56
100°C (212°F) 6.1
For checking elements where temperature
overrun is occurring, check that contactor
releases (opens) when temperature control
switches OFF. If not, contacts of the contactor
have welded shut and elements will be ON and
heating will be continuous. Contactor is faulty—
replace.
Element faulty (blown)
With the controller on and calling for heat check
voltage across element terminals at RH side of
oven. If the voltage is correct then check the
current draw of element. If there is no current
draw then element is faulty—replace.
If there is no voltage then check voltage is
being supplied to each element coil from the
heating contactor. If no voltage to elements,
check contactor operation and wiring.
Correct element current draw:
Inner Coil 9.0A ± 2.5%
Outer Coil 11.9A ± 2.5%
Correct element resistance:
Inner Coil 26.8 ohms ± 5.0%
Outer Coil 20.2 ohms ± 5.0%
Figure 5.3.3a
Relay #2
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