Moffat E27-2 Service Manual

E27 CONVECTION OVEN

SERVICE

MANUAL

Revision 1/F3563

September, 2001

Manual P/N M0ME27

CONTENTS

This manual is designed to take a more in depth look at the E27 convection oven 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 those special cases where these settings are required to change, 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 ...................................................................................................................8

3.1 Description of Controls

3.2 Explanation of Control System

4. MAINTENANCE .............................................................................................................10

4.1 Cleaning

4.2 Routine Procedures

5. TROUBLE SHOOTING GUIDE .....................................................................................11

6. SERVICE PROCEDURES ..............................................................................................14

6.1 Fault Diagnosis

6.2 Access

6.3 Replacement

6.4 Adjustment / Calibration

7. ELECTRICAL SCHEMATICS ........................................................................................27

8. ELECTRICAL WIRING DIAGRAMS ..............................................................................28

9. SPARE PARTS ..............................................................................................................29

10. ACCESSORIES / OPTIONS ..........................................................................................30

IMPORTANT: MAKING ALTERATIONS MAY VOID WARRANTIES AND APPROVALS.

Revision 1/F3563

-3-

11. PARTS DIAGRAM .........................................................................................................31

11.1 Main Assembly

11.2 Control Panel Assembly

12. SERVICE CONTACTS ..................................................................................................35

APPENDIX A. DOUBLE STACKING KIT ...............................................................................37

Revision 1/F3563

-4-

MODEL: E27

1. SPECIFICATIONS

FRONT

945

(37.2)

791

(31.1)(3.0)

725

(28.5)

430

120

(4.7)

(1.75)

236

(9.3) (15.6)

395

(16.9)

SIDE

PLAN

LEGEND

- Electrical connection entry point

Dimensions shown in millimetres. Dimensions in inches shown in brackets.

Revision 1/F3563

-5-

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 695 mm / 27 3/8” Height 285 mm / 11 1/4” Depth 505 mm / 19 7/8” Oven Volume 0.10 m³ / 3.5 ft³

OVEN RACK SIZE

Width 660 mm / 26” Depth: 460 mm / 18”

ELECTRICAL SUPPLY SPECIFICATION OPTIONS

208-220V ac, 50/60Hz, 14.4A, 3.0kW @ 208V 230-240V ac, 50/60Hz, 12.5A, 3.0kW @ 240V

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

Revision 1/F3563

-6-

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 important that the oven is installed correctly and that the operation is correct before use. Installation shall comply with local electrical, health and safety requirements.

BEFORE CONNECTION TO POWER SUPPLY

Unpack and check unit for damage and report any damage to the carrier and dealer. Report any deficiencies to your dealer. Check that the available power supply is correct to that shown on the rating plate located on the righthand side panel.

208-220V ac, 50/60Hz, 14.4A, 3.0kW @ 208V 230-240V ac, 50/60Hz, 12.5A, 3.0kW @ 240V

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”

ELECTRICAL CONNECTION

E27 convection ovens are supplied with pre-fitted cords. Ensure unit is fitted with the correct cord and plug for the installation. Refer specifications section. Should changing of the cord be necessary, gain access to the electrical connection terminal block, grounding lug, and strain relief by removing the back panel (four screws).

Figure 2.1

RATING PLATE LOCATION The rating plate for the E27 convection oven

is located at the bottom left corner of the RH side panel.

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 ensure the oven is level from side to side and front to back. (If this is not carried out, uneven cooking could occur). The feet used with bench 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.

BEFORE USE Operate the oven for about 1 hour at 200°C

(400°F) to remove any fumes or odours which may be present.

Revision 1/F3563

Rating Plate

Figure 2.2

-7-

3. OPERATION

NOTE: A full user’s operation manual is supplied with the product and can be used for further

referencing of installation, operation and service.

3.1 DESCRIPTION OF CONTROLS

1. POWER

Depress to switch power on or off (switch illuminates when power is on).

2. THERMOSTAT Temperature range 50 - 250°C (120 - 480°F). Indicator illuminates when elements are cycling ON to maintain set temperature.

3. BAKE TIMER

1 Hour bake timer. (Indicator illuminates when “time up” (0) reached, and buzzer sounds).

4. LIGHT SWITCH Push switch to activate light. (Oven light illuminates while button depressed).

Revision 1/F3563

-8-

3.2 EXPLANATION OF CONTROL

SYSTEM

The E27 Turbofan convection ovens feature multi-function operator controls for which a correct understanding of their operation is required before carrying out any service or fault repair work. The control device functions are explained as follows:

A power switch on the control panel isolates power to all the controls of the oven. With the power switch Off all functions of the oven are inoperable.

NOTE: The supply voltage is fed to the input side of the heating element power relay whenever the electrical supply is on.

With the power switch On (illuminated) power is directly supplied to the 60 minute bake timer, door microswitch, and the light switch. The light switch will turn the oven light on when the door is closed, but only whilst the light switch is held in.

The door microswitch on the E27 oven controls the light, the circulation fan, and the fan element. Hence, opening the door on the E27 oven causes the circulation fan and fan element to switch off, as well as causing the oven light to come on.

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 run down to zero and at this point will remain On continuously until the 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 temperature control of these ovens is with a capillary type thermostat which can be set to a required cooking temperature.

The E27 has an element coiled around the circulation fan in the rear of the oven. Power to the element is provided via a heating power relay located at the rear of the oven. When the thermostat calls for heat, it energises this relay, which switches power to the fan

element. The control panel indicator light above the thermostat knob cycles on and off with the thermostat to indicate when the element is on and the oven is heating. In the ‘Off’ position, the element relies on the thermostatic control to prevent it switching on. Accordingly, if the oven temperature drops below approximately 20°C the thermostat and element may cycle on at this setting.

The circulation fan on the E27 oven reverses direction every 90 seconds for a 50Hz supply (every 75 seconds for 60Hz). Prior to a change of direction the fan motor is switched off for 10 seconds (8½ seconds for 60Hz) to allow the motor/fan to slow down. Cycling of the fan motor is controlled by a continuous cam timer with electric motor. The timer has two cams and switches which supply power alternately to one of two motor supply wires, causing the motor to alternate direction. During the fan motor slow down periods, both cam switches are open and power is not supplied to either of the motor supply wires. When the oven door is opened or the power is switched off the cams will stop. When the oven door is closed or the power switched back on the cam timer will resume its cycle from the point where it stopped.

The fan motor is a split phase continuous capacitor motor with the capacitor externally connected across the motor supply leads. The motor also incorporates an internal thermal trip switch for overheat protection which is auto resetting.

The following Troubleshooting Guide (section

5) should be used to identify any incorrect oven operation. On correct identification of the operating fault the Troubleshooting 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.

Revision 1/F3563

-9-

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 TO CLEAN INTERIOR OR EXTERIOR OF THIS UNIT.

EXTERIOR Clean with a good quality stainless steel

cleaning compound. Harsh abrasive cleaners may damage the surface.

INTERIOR Ensure that the oven chamber is cool. Do not

use wire brushes, steel wool or other abrasive materials. Clean the oven regularly with a good quality oven cleaner. Take care not to damage the fan or the tube at the right side of the oven which controls the thermostat.

OVEN RACKS

To remove, slide out to the stop position, raise the front edge up, and lift out.

SIDE RACKS Undo the thumbscrew (anti-clockwise rotation)

securing rack to oven wall, swing rack towards centre of oven to disengage location pin at front of side, and pull rack forward to remove. To replace, engage rack in rear holes, swing towards side of oven to engage in front hole, and replace thumbscrew.

FAN BAFFLE

To remove, loosen thumbscrews (anticlockwise rotation) at top of baffle. Lift baffle to disengage from locating studs and thumbscrews then pull forward to remove. Replace in reverse order.

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. To replace the top seal, ensure that the lip is facing the oven opening. The left, right and bottom seals have the lip facing out. Fit the top and bottom seals first, then the side seals.

OVEN DOOR GLASS

Clean with conventional glass cleaners

4.2 ROUTINE PROCEDURES

DOOR SEALS

Check for deterioration 12 months

ELEMENTS Check that element resistances 12 months

are correct to their ratings (refer

6.3.9)

Revision 1/F3563

-10-

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.

FAN ONLY OPERATES IN ONE DIRECTION

OVEN LIGHT NOT ILLUMINATING - DOOR OPEN

OVEN LIGHT NOT ILLUMINATING - DOOR 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 obstructed. Door microswitch is 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)

Motor timer faulty.

(Refer fault diagnosis 6.1.2)

Motor capacitor faulty.

(Refer fault diagnosis 6.1.2)

Wiring.

Motor timer faulty.

(Refer fault diagnosis 6.1.2)

Blown bulb.

No power to light.

(Refer fault diagnosis 6.1.3)

Blown bulb.

Light switch faulty.

(Refer fault diagnosis 6.1.4)

Turn on.

Depress switch. Switch will illuminate.

Ensure electrical supply correct.

Replace.

(Refer service section 6.3.4)

Close door. Clear obstruction. Adjust.

(Refer service section 6.4.2)

Replace.

(Refer service section 6.3.2)

Replace.

(Refer service section 6.3.11)

Replace.

(Refer service section 6.3.12)

Replace.

(Refer service section 6.3.13)

Check and tighten any loose wiring.

Replace.

(Refer service section 6.3.13)

Replace.

(Refer service section 6.3.1)

Correct fault.

Replace.

(Refer service section 6.3.1)

Replace.

(Refer service section 6.3.4)

Revision 1/F3563

-11-

FAULT POSSIBLE CAUSE REMEDY

60 MINUTE TIMER WILL NOT TIME DOWN

60 MINUTE TIMER INACCURATE BELOW 20 MINUTES

60 MINUTE TIMER NO TIME UP BUZZER

60 MINUTE TIMER NO TIME UP INDICATOR

NO HEAT - FAN ELEMENT NOT WORKING

NO TEMPERATURE CONTROL

Timer faulty.

Timer not set correctly.

Zero (time up) position not set correctly.

Buzzer faulty.

(Refer fault diagnosis 6.1.5)

Timer not switching on buzzer.

(Refer fault diagnosis 6.1.5)

Indicator faulty.

(Refer fault diagnosis 6.1.6)

No power to thermostat. (Refer fault diagnosis 6.1.7)

Thermostat faulty.

(Refer fault diagnosis 6.1.7)

Fan element not working.

(Refer fault diagnosis 6.1.7)

Heating power relay faulty. (Refer fault diagnosis 6.1.7)

Thermostat faulty.

(Refer fault diagnosis 6.1.8)

Heating relay faulty. (Refer fault diagnosis 6.1.8)

Replace.

(Refer service section 6.3.6)

For timer settings below 20 minutes, always rotate past 20 minutes, then back to desired time.

(Refer service section 6.4.3)

Replace.

(Refer service section 6.3.5)

Replace timer.

(Refer service section 6.3.6)

Replace.

(Refer service section 6.3.3)

Identify fault and correct.

Replace.

(Refer service section 6.3.7)

Replace.

(Refer service section 6.3.9)

Replace.

(Refer service section 6.3.8)

Replace.

(Refer service section 6.3.7)

Replace. (Refer service section 6.3.8)

SLOW RECOVERY Overloading of oven.

Electrical supply incorrect.

Fan not working. Thermostat calibration.

(Refer fault diagnosis 6.1.9)

NO THERMOSTAT HEATING INDICATOR LIGHT

Revision 1/F3563

Indicator faulty.

(Refer fault diagnosis 6.1.10)

-12-

Reduce oven loading. Check supply voltage is as per

rating plate voltage. Check fan operation. Correct calibration.

(Refer service section 6.4.1)

Replace.

(Refer service section 6.3.3)

FAULT POSSIBLE CAUSE REMEDY

DOOR DOES NOT CLOSE Tray in way of door.

Door seal obstruction.

Door hinges worn.

Door hinge counter brackets worn.

DOOR SEAL LEAKS Door seal damaged.

Door seal incorrectly fitted.

Correctly position tray in rack. Correctly install door seal.

(Refer service section 6.3.16)

Replace.

(Refer service section 6.3.18)

Replace. (Refer service section 6.3.19)

Replace. (Refer service section 6.3.16)

Correctly install door seal.

(Refer service section 6.3.16)

Revision 1/F3563

-13-

+ 25 hidden pages