Moffat E31 Service Manual
E31 CONVECTION OVEN
Applies to Units from S/N 40423
SERVICE
MANUAL
Revision 2F/3506
October, 2002
Manual P/N MOME31
WARNING: ALL INSTALLATION AND SERVICE REPAIR WORK MUST BE CARRIED
OUT BY QUALIFIED PERSONS ONLY.
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CONTENTS
This manual is desig ned to take a more in depth look at the E31 c onvec tio n ov en for the purpose of
making the unit more understandable to service people.
There are settings explained in this manual that should never require to be adjusted, but for
completeness and thos e special cases where thes e settings are required to ch ange, this manual
gives a full explanation as to how, and what effects will result.
SECTION PAGE NO.
1. SPECIFICATIONS .........................................................................................................5
2. INSTALLATION .............................................................................................................7
3. OPERATION ..................................................................................................................9
3.1 Description of Controls
3.2 Explanation of Control System
4. MAINTENANCE .............................................................................................................12
4.1 Cleaning
4.2 Routine Procedures
5. TROUBLE SHOOTING GUIDE ......................................................................................14
6. SERVICE PROCEDURES .............................................................................................17
6.1 Fault Diagnosis
6.2 Access
6.3 Replacement
6.4 Adjustment / Calibration
7. ELECTRICAL SCHEMATICS ........................................................................................32
8. ELECTRICAL WIRING DIAGRAMS ..............................................................................33
9. SPARE PARTS ..............................................................................................................34
10. ACCESSORIES / OPTIONS ..........................................................................................35
11. PARTS DIAGRAM .........................................................................................................36
11.1 Main Assembly
11.2 Control Panel Assembly
12. SERVICE CONTACTS ..................................................................................................41
APPENDIX A. POWER RELAY UPGRADE KIT ...................................................................43
IMPORTANT: MAKING AL TERATIONS MAY VOID WARRANTIES AND APPRO VA LS.
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MODEL: E31
1. SPECIFICATIONS
(1.55)
FRONT
(28.35)
(4.70)
(23.60)
(23.10)
(6.30)
(1.85)
SIDE
PLAN
LEGEND
- Electrical connection entry point
Dimensions shown in millimetres.
Dimensions in inches shown in brackets.
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- Water entry - 9mm /
3
/8” I.D male hose connection
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LOCATION
To ensure correct ventilation for the motor and
controls the following minimum installation
clearances are to be adhered to:
Rear 25mm / 1”
Left-hand side 25mm / 1”
Right-hand side 25mm / 1”
OVEN INTERNAL DIMENSIONS
Width 468 mm / 18.5”
Height 418 mm / 16.5”
Depth 432 mm / 17”
Oven Volume 0.08 m³ / 3.0 ft³
OVEN RACK SIZE
Width 460 mm / 18”
Depth: 370 mm / 14.5”
ELECTRICAL SUPPLY SPECIFICATION
OPTIONS
208 V AC 60 Hz, 14.6 A, 3.2kW @ 208 V
220-240 V AC 60 Hz, 13.0 A, 3.1kW @ 240 V
208-220 V AC 50 Hz, 14.6 A, 3.2kW @ 220 V
230-240 V AC 50 Hz, 13.0 A, 3.1kW @ 240 V
ELECTRICAL PLUG SPECIFICATION
REQUIREMENTS
Australia 3-pin 250V 15A, AS/NZ 3112
Canada 3-pin 250V 15A, NEMA 6-15
New Zealand 3-pin 250V 15A, AS/NZ 3112
United Kingdom 3-pin 250V 13A fused, BS
1363A
United States 3-pin 250V 15A, NEMA 6-15
Other Countries 3-pin 250V 13A minimum,
type to meet country stan-
dards
WATER SUPPLY CONNECTION
Max Pressure 550 kPa / 5.5 bar / 80 psi
Min Pressure 100 kPa / 1.0 bar / 15 psi
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2. INSTALLATION
WARNING: THIS APPLIANCE MUST BE GROUNDED.
WARNING: ALL INSTALLATION AND SERVICE REPAIR WORK MUST BE CARRIED
OUT BY QUALIFIED PERSONS ONLY.
It is most im portant that the oven is instal led
correctly and that the operation is correct
before use. Installation shall comply with local
electrical, health and safe t y requirements.
BEFORE CONNECTION TO THE POWER
SUPPLY
Unpack and check unit f or dam age and repor t
any damage to the c arrier and dealer . Repor t
any deficiencies to your dealer. Fit the feet
which are packed inside the oven. Fit door
handle to oven door. Chec k that the avai lable
power supply is correc t to that shown on the
rating plate located on the right-hand side
panel (refer figure 2.3).
208 V AC 60 Hz, 14.6 A, 3.2kW @ 208 V
220-240 V AC 60 Hz, 13.0 A, 3.1kW @ 240 V
208-220 V AC 50 Hz, 14.6 A, 3.2kW @ 220 V
230-240 V AC 50 Hz, 13.0 A, 3.1kW @ 240 V
LOCATION
To ensure correct ventilation for the motor and
controls the following minimum installation
clearances are to be adhered to:
Rear 25mm / 1”
Left-hand side 25mm / 1”
Right-hand side 25mm / 1”
IMPORTANT: THE OVEN VENT
LOCATED ON THE CABINET TOP
MUST NEVER BE OBSTRUCTED.
Position the oven in its allocated working
position. Use a spirit level to ensur e the o ven
is level from side to s ide and f ront to b ack. ( If
this is not carried out, uneven cooking could
occur). The feet/legs used with bench or f loor
mounting or provided with stands are
adjustable and will require adjusting in
levelling the unit. It should be positioned so
the operating panel and oven shelves are
easily reachable for loading and unloading.
DOUBLE STACKING UNITS
When it is desired to m ount one unit on top of
another the 31mm (1¼") high spacer feet
must be used. These short feet should be
screwed on, and the unit lifted on top of the
bottom unit, where it locates safely under its
own weight, for normal applications.
BEFORE USE
Operate the oven for about 1 hour at 200°C
(400°F) to remove an y fumes or odours which
may be present.
ELECTRICAL CONNECTION
E31 convection ovens are supplied with
pre-fitted cords. Ensure unit is fitt ed with the
correct cord and plug for the installation (refer
specifications section).
Figure 2.1
Should changing of the cord be necessary,
gain access to the electrical connection
terminal block and strain relief by removing
the back panel (four screws).
WATER CONNECTION
A cold water supply should be fitted to the
water inlet (9mm /
is located on the re ar of the left hand side of
the unit.
Connect water supply - Max inlet pressure
80psi / 550kPa.
Turn on water supply to check for leaks.
IMPORTANT: MAXIMUM INLET WATER
PRESSURE IS 550 kPa / 80 psi.
3
/8” hose connection) which
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DOOR HANDLE INSTALLATION
1. Open oven door.
2. Remove two screws (item 2).
3. Remove the two screws (item 3) from the
handle (item 1).
4. Install the handle bracket through the slot
on the door side.
5. Screw in the t wo screws (item 2) fully, then
fully screw in the previous two scr ews (item
3). Ensure that they are tight.
1
3
2
Figure 2.2
RATING PLATE LOCATION
The rating plate for the E3 1 convection oven is
located at the b ottom left cor ner of the RH side
panel.
Ratin g Plate
Figure 2.3
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3. OPERATION
NOTE: A full user’s operation m anual is supplied with the product and can be used for further
referencing of installation, operation and service.
3.1 DESCRIPTION OF CONTROLS
1
2
3
4
5
1. POWER
Depress to switch power on or off (switch
illuminates when power is on).
2. THERMOSTAT
Temperature range 50 - 280°C (120 - 550°F).
Indicator illuminates when elements are
cycling ON to maintain set temperature.
GRILL POSITION - The GRILL indicator will
illuminate indicating that the GRILL function
has been set. The HEATING indicator will
also illuminate whenever the elements are on.
3. BAKE TIMER
1 Hour bake timer.
(Indicator illuminates when “time up” (0)
reached, and buzzer sounds).
4. ROAST N HOLD
Depress switch to activate ’ROAST N HOLD’
function (Switch illuminates when ON).
5. ROAST TIMER
3 Hour roast timer.
(Indicator illuminates when “time up” (0)
reached, and product held at 75°C (167°F).
6. STEAM SWITCH
Push switch to activate water injection (W ater
injects into oven while the button is
depressed).
7. LIGHT SWITCH
Push switch to activate oven light.
(Light illuminates while button depressed).
6
7
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3.2 EXPLANATION OF CONTROL
SYSTEM
The E31 Turbofan convection oven features
multi-function operator controls for which a
correct understanding of their operation is
required before carrying out any service or
fault repair work . The contr ol devic e func tions
are explained as follows:
A power switch on the control panel isolates
all to the controls of the oven. With the power
switch Off all functions of the oven are
inoperable.
With the power switch O n (illuminated) power
is directly supplied to the 60 minute bake
timer, steam (water injection) switch, door
microswitch, light s witch, and the temperature
control circuit. Accordingly the oven
circulation fan will operate when the door is
closed, and with do or open the oven light will
come on and the circulation fan will shut
down, as these are controlled via the door
microswitch. The control panel light switch
will turn the oven light on when the door is
closed only when the light switch is held in.
The 60 minute timer is a mechanical timer and
can therefore be operated with the oven’s
power switch On or Off. However, only with
the oven’s power switch On will the switch
contacts of the 60 minute timer turn on the
time-up buzzer and illuminate the time-up
indicator on the control panel. The buzzer
and time-up indicator provide indication that
the time setting has r un down to zero and at
this point will rem ain On continuous ly until th e
60 minute timer has been manually set back
to the Off (vertical) position. The 60 minute
timer does not control any other part of the
oven’s operating system as this timer is
independent of the temperature control and
heating system.
The steam (water injection) switch on the
control panel can be operated whenever the
power switch is On . The switc h is m omentary
like the light s witch and when depress ed, will
operate the electric s olenoid valve at the rear
of the oven and inject water into the water
trough at the bottom of the left hand sid e rack
in the oven. Rele asing the steam button will
close the solenoid val ve. This f eature is used
to instantaneousl y add moisture into the o ven
cavity, or to introduce a reservoir of water in
the water trough to maintain humidity in the
oven chamber and minimise product’s
moisture loss during cooking.
The temperature contr ol of this oven is with a
capillary type thermostat which can be set to a
required cooking temperature, or set to the
Grill/Broil position to provide top browning or
grilling/broiling in the oven.
The thermostat s witch has a separate switch
body assembled on to the front from the s haft
assembly and when th e thermostat is s et to a
cooking temperature, one set of contacts is
closed to switch power from the oven
thermostat to the bottom heating element in
the oven. The second switch contact of this
switch assembl y remains open in this setting
and isolates power f rom the top elem ent inner
coil. The top element outer coil is directly
switched on from the oven thermostat.
Accordingly only the top outer element and
the bottom element ar e used when a cooking
temperature is selected. The control panel
indicator light above the thermostat knob
cycles On and Off with the thermostat to
indicate when the elements are on and the
oven is heating.
When the thermostat c ontrol is set to the Grill
position the firs t switch con tact opens and the
second switch contact closes. This
arrangement allows power to be provided to
the top element inner coil when the thermostat
is On, and isolates power from going to the
bottom heating element. The top element
outer coil which is directly fed from the oven
thermostat switch is therefore On in
conjunction with the top element inner coil
when the thermostat is set to the Grill position.
As both the top i nner and outer elem ent coils
are thermostatically controlled, the elements
will cycle On/Off with the door closed as the
thermostat setting in the Grill position is 300°C
(600°F). If the Grill position is selected with
the door open, the elements will remain On
continuously and the circulation fan will be
turned Off. The control panel Grill indicator
will illuminate when the thermostat is set to
the Grill position and will cycle On and Off
with the main heating indicator light.
The E31 Turbofan convec tion oven features a
Roast-and-Hold system which can be used to
automatically set the oven to a fixed holding
temperature at the end of a timed cooking
period. When the Roast-and-Hold switch is
turned On the switch will illuminate and turn
on a mini-contactor found on the inside of the
control panel. W hen the contac tor is s witch ed
On a normally closed switch pole on the
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contactor is open and the normal power
supply to the oven thermostat is isolated. A
second normally open switch pole is closed
and this provides power to the 3 hour roast
timer.
If the roast timer is in the Hold (vertical)
position the timer switch contacts will be in
their normally closed position and supply
power directly to the Hold ther mostat located
behind the control panel. The Hold
thermostat is fac tory set to 75°C (167°F) and
will directly supply power to the bottom
heating element as required to maintain its
preset temperature.
If the main therm ostat is t urned On , p ower wil l
also be supplied t o the top outer elem ent coil
through the first switch contact of the
thermostat front switch assembly. In this case
the thermostat heat ing light will also c ycle O n/
Off as the Hold thermostat maintains
temperature.
In the Roast-and Hold m ode the 3 hour timer
can be set to a selecte d roas ting tim e. Dur ing
this time period the normally open switch
contacts of the timer are closed. The timer
has two change over switches and in this
position one is used to supply power to its
timing motor and the other is used to switch
power directly to the main oven thermostat.
During the 3 hour timer run-down period the
oven temperature will be controlled by the
main oven therm ostat to the set temperature
and operate as previously described.
When the 3 hour timer has run down and
reached the Hold position the two switch
contacts change over to th eir normally closed
position which isolates power from the timer
motor and the oven thermostat. It also
switches power back to the oven hold
thermostat. At this point the temperature
control is now maintained by the hold
thermostat as previously described. To
cancel the hold circuit the Roast-and-Hold
switch is turned Off. This turns off the
contactor which removes power from the 3
hour timer and closes the contactor pole on
the contactor that feeds the main oven
thermostat.
The factory preset hold thermostat can be
adjusted as required to change the holding
temperature if necessary. Refer Service
section for this procedure.
The following Troubleshooting Guide should
be used to identify any incorrect oven
operation. On correct identification of the
operating fault the T roubleshooting Guide will
make reference to the corrective action
required, or refer to the Fault Diagnosis
section and/or Service section to assist in
correction of the fault.
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4. MAINTENANCE
WARNING: ALL INSTALLATION AND SERVICE REPAIR WORK MUST BE CARRIED
OUT BY QUALIFIED PERSONS ONLY.
4.1 CLEANING
WARNING: ALWAYS TURN THE
POWER SUPPLY OFF BEFORE
CLEANING.
IMPORTANT: THIS UNIT IS NOT
WATER PROOF.
DO NOT USE A WATER JET SPRAY T O
CLEAN INTERIOR OR EXTERIOR OF
THIS UNIT.
EXTERIOR
Clean with a good quality stainless steel
cleaning compound. Harsh abr asive clean ers
may damage the surface.
INTERIOR
Ensure that the oven cham ber is cool. Do not
use wire brushes, steel wo ol or other abras ive
materials. Clean the oven regularly with a
good quality oven cleaner. Take care not to
damage the fan or the tube at the r ight side of
the oven which controls the thermostat.
OVEN RACKS
To remove, slide out to the s top position, raise
the front edge up, and lift out.
SIDE RACKS
To remove, tak e hold of the centre rung and
swing towards the oven top. T o replace, hold
horizontally, engage in holes and swing down.
FAN BAFFLE
To remove, unscr ew the ov en lamp gl ass and
lift the baffle out. To replace, locate the
bottom edge of the baffle over the bottom
element terminal plate and secure in place
with the oven lamp glass.
IMPORTANT: DO NOT OVER
TIGHTEN LAMP GLASS.
OVEN SEALS
To remove, hold at their centre point and
pull forward until they unclip. Remove side
seals first, then top and bottom. The seals
may be washed in the sink, but take care not
to cut or damage them. T o replace, ensure
that the lip is facing the oven opening. Fit
the top and bottom seals first, then the s ide
seals.
OVEN DOOR GLASS
Clean with conventional gla s s cleaners
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4.2 ROUTINE PROCEDURES
PROCEDURE INTERVAL
DOOR SEALS Check for deterioration. 12 months
DOOR PIVOT BUSHES Check for wear. 12 months
DOOR CATCH Ensure that catch is adjusted such that the door closes
properly.
ELEMENTS Check that element res istances are c orrect to their r ating
(refer 6.3.13)
WATER NOZZLE Check for liming / scale build-up in water nozzle. 12 months
12 months
12 months
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5. TROUBLE SHOOTING
WARNING: ALL INSTALLATION AND SERVICE REPAIR WORK MUST BE CARRIED
OUT BY QUALIFIED PERSONS ONLY.
FAULT POSSIBLE CAUSE REMEDY
THE OVEN DOES NOT
OPERATE / START
FAN DOESN’T OPERATE Door not closed.
The mains isolating switch on
the wall, circuit breaker or fuses
are “off” at the power board.
The power switch on the oven is
off.
Incorrect electrical supply.
(Refer fault diagnosis 6.1.1)
Power switch on unit faulty.
(Refer fault diagnosis 6.1.1)
(Fan only operates with door
closed).
Door microswitch out of
adjustment.
(Refer fault diagnosis 6.1.2)
Door microswitch faulty
(Refer fault diagnosis 6.1.2)
Fan motor faulty.
(Refer fault diagnosis 6.1.2)
Wiring.
Turn on.
Depress switch. Switch will
illuminate.
Ensure electrical supply correct.
Replace.
(Refer service section 6.3.4)
Close door.
Adjust.
(Refer service section 6.4.2)
Replace.
(Refer service section 6.3.2)
Replace.
(Refer service section 6.3.15)
Check and tighten any loose
wiring.
OVEN LIGHT NOT
ILLUMINATING - DOOR OPEN
OVEN LIGHT NOT
ILLUMINATING - DOOR
CLOSED
NO WATER INJECTION /
STEAM
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Blown bulb.
No power to light.
(Refer fault diagnosis 6.1.3)
Blown bulb.
Light switch faulty.
(Refer fault diagnosis 6.1.4)
Water not turned on.
Oven water nozzle block ed.
Fault with water valve.
(Refer fault diagnosis 6.1.5)
Steam switch faulty.
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Replace.
(Refer service section 6.3.1)
Replace.
(Refer service section 6.3.1)
Replace.
(Refer service section 6.3.4)
Turn water on at water supply.
Remove, clean or replace.
(Refer service section 6.3.13)
Service or replace as required.
(Refer service section 6.3.11,
6.3.12)
Replace.
(Refer service section 6.3.4)
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