Merrychef Evolution User manual

Page 1
CAUTION MICROWAVE EMISSIONS
DO NOT BECOME EXPOSED TO EMISSIONS FROM THE MICROWAVE
GENERATOR OR PARTS CONDUCTING MICROWAVE ENERGY
SERVICE MANUAL
Evolution
SERVICE MANUAL
For all Evolution models manufactured from January 2001
Part No. 32Z3382e Issue No. 3

Page 2
Table of Contents
Safety Code................................................................ 3
Product Specifications ................................................4
Dimensions. Location and Installation ........................ 5
Manual RHS controls..................................................7
Error Codes and Diagnostics......................................8
Main Features............................................................ 9
A -Power Output Testing to EN 60335-2-90:1996..... 10
B - Power Output Testing.......................................... 11
C - Power Transformer Test ..................................... 11
D - High Voltage Capacitor Test ...............................12
E - High Voltage Rectifier Test.................................. 12
Principal Components: Right side view..................... 13
Principal Components: Right side view..................... 14
Principal Components: Rear view, top view.............. 15
Oven Door Assembly................................................ 16
Door Interlock Operation........................................... 17
Error Light Operation ...............................................17
Input Wiring Details................................................... 18
Control Panel Assembly............................................ 19
Membrane Panel Circuit............................................ 20
Circuit Diagram.................................................21 & 22
Parts Matrix............................................................... 23
Reply Form............................................................... 24
Merrychef Limited,
Station Road West,
Ash Vale,
Aldershot, Hampshire GU12 5XA,UK.
Tel: [phone] Fax: [phone]
Internet address: http://www.merrychef.co.uk
E-mail: [e-mail] or [e-mail]

Page 3
This manual is designed to assist engineers who have been on a recognised product familiarisation
and training course run by Merrychef Limited. It has been prepared to offer technical guidance for the
Merrychef Evolution range of Combination Microwave Ovens.
Please remember that it is wiser not to attempt a service task if you are unsure of being able to
complete it competently, quickly, and above all safely.
To avoid injury to yourself, and to protect the appliance from possible damage, please follow this
Safety Code when servicing these ovens.
Before attempting to repair the oven, check it for microwave leakage.
Check that the oven is not emitting microwaves, even when supposedly not in operation.
Check that the oven is not operating continuously, whether the display indicates cooking
or not.
Always discharge the HT capacitors before working on the oven using a suitably insulated
10 MΩResistor
Before removing the rear cover from the oven, do all of the following:
•Switch off the mains supply and remove the plug from the wall socket.
or •If the oven is hard wired, ensure that the power is turned off at the isolator switch.
Note: The On/Off switch on the oven is not adequate protection against electric shock, as it does
not isolate all of the internal wiring from the mains.
Upon completion of a service on a Evolution oven, or before reconnecting the appliance to the mains
supply for testing, check all of the following points:
•All internal electrical connections are correct.
•All wiring insulation is correct and is not touching a sharp edge.
•All Earth connections are electrically and mechanically secure.
•All four door safety interlocks are secure and mechanically sound.
•The door operation is smooth, and the arms run freely in the slots.
•The door activates all four of the door interlock switches in the correct order.
•All fuse-holder safety covers are correctly fitted.
•The temperature sensor is correctly connected to the Power PCB.
Before finishing the service call, recheck the following points:
•All of the electronics are functioning correctly, and all of the touch pads are working
•The turntable is rotating freely
•The power output of the oven is correct
•Microwave emission is below permissible limit - 5 mW/cm² (see BS EN 60335-2-90:1998)
•Oven has correct 120 mm air gap all round and 100 mm above. Air flow should not be
restricted
SAFETY CODE

Page 4
Model Number: EV + Voltage + Frequency + Phase + Version
Power Output Microwave 100%
Convection Heat
Combination
2000 Watts (IEC 705 Rating) Single & Twin supply
1800 Watts (IEC 705 Rating) Three Phase supply
5000 Watts
2000 Watts Microwave + 5000 Watts Convection Heat
External
Dimensions Height
Width
Depth
700 mm (Plus 100 mm minimum clearance above = 800 )
755 mm (Plus 100 mm minimum clearance each side = 955 )
555 mm (Plus 100 mm clearance behind = 655 )
Internal
Dimensions Height
Width
Depth
Turntable
Capacity
315 mm
330 mm
330 mm
300 mm Diameter
34.3 litres (1.21 ft³)
Weight Net
Gross packed 82 kg 90 kg
Construction Cavity
Casework 304 Stainless Steel 304 Stainless Steel
Settings Microwave
Temperature
Timer
100%,75%,50%,25%, Convection only
Off, 150°, 200°, 250°, 275°,300°C
Up to 30 minutes (Manual)
3 cooking stages of up to 30 minutes each (Programed)
Control System Wipe-clean touch pad operating microprocessor based control system
Single touch control of temperature
Direct readout of time, power and temperature set
Digital readout of cavity temperature available
100 Pre-programmed cooking sequences
Built-in diagnostic messages
Safety
Features Four door interlock switches
Cavity Overheat Sensor
Magnetron Overheat Sensor
Blocked Air Filter Sensor
Automatic Lock-out on invalid time setting
Convection Fan and Heater disabled when door open
Additional
Features •Easy-to-use multistage programming
•Manual and Pre-programmed mode always available
•Rapid cavity pre-heat
•Low-loss insulated cavity and door
•One-touch selection of temperature
•Magnetron soft-start circuit for increased life and faster activation
PRODUCT SPECIFICATIONS
Power Requirement Voltage Current Microwave Convection Combination
Single EV2451B 240V 45A 20A 21A 41A
P1 240V 25A 20A 1A 20A
P2 240V 25A 0 20A 20A
Twin EV2452B
Model prefix Voltage Frequency Phase Control Type
24=240V 5 = 50 Hz
6 = 60 Hz 1 = Single 2 = Twin
3= Three Phase
B
EV

Page 5
DIMENSIONS AND LOCATION
A sample of this product has been tested and found to be in conformity
with the following directives:
Directive
EMC 89/336 EEC EN 55011
EN 50082-1 1991 (Emissions) 1992 (Immunity)
LVD 73/23 EEC EN 60 335-2-90
Harmonised standards applied.

Page 6
Power Supply Requirements
The Evolution should be connected to a suitable electricity supply, which can cope with the
switching-on surge that occurs with certain types of catering equipment, such as microwaves.
Because of this requirement, we strongly recommend that a separate, suitably rated supply is
installed for the oven.
The supply for the oven should be fitted with a Type "C" circuit breaker. Please refer to rating
plate for details.
If the oven is hard wired to the supply a double-pole isolator switch with a contact gap of at least
3mm should be fitted.
Positioning the Oven
In order to maintain adequate ventilation for air intake and exhaust, and to allow access for
cleaning filters, you must allow a minimum of 100 mm clearance at the sides and 100 at the rear
of the oven, and at least 100 mm above. Air intake temperature should not exceed 35°C -
excessive temperature can lead to reduced operating duty cycle or premature ageing of internal
components.
NEVER Install an oven above fryers, grills, griddles or any other major heat source.
NEVER Stack machines on top of each other - always use a double stand.
INSTALLATION INSTRUCTIONS

Page 7
MANUAL CONTROLS
below 100ºC 100C-125ºC above 125ºC
1 POWER PADS
2 CONVECTION PAD
3 TIME/PROGRAM SELECT PADS
4 TEMPERATURE SETTING PADS
5 CANCEL PAD
6 PROGRAM PAD
7 TIME AND PROGRAM DISPLAY
8 MULTI-STAGE INDICATOR
9 COLON
10 ON/OFF SWITCH
11 ERROR DISPLAY
7 TIME AND
PROGRAM
DISPLAY
1. POWER PADS
There are 4 Microwave Power Pads to select from:
25%, 50%, 75%, and 100%. A light will indicate the
one in use.
2. CONVECTION PAD
This is used when foods only require browning( no
microwave)
Note: when cooking the MICROWAVE and
CONVECTION pads start the cycle and timer. You
may alter power levels during a manual cooking cycle.
When cooking is interrupted, a light will flash as a
reminder that the time is being held (see PAUSE).
3. TIME/PROGRAM SELECT PADS
These pads are used for setting the cooking time in 1
second steps to a maximum of 30 minutes.
They are also used for programs from 21-99.
4. TEMPERATURE SETTING PADS
These pads are used to set the convection
temperature. A light will indicate the temperature set.
Selecting the ‘0’key will switch convection off. If a
temperature key is pressed and held the current oven
temperature will be displayed in the time display
window.
5. CANCEL/ CALLBACK ‘C’PAD
Cancels all timed cooking cycles, pre-programmed
operations and stop the microwave energy. It does not
alter the oven temperature . If the oven is hot food will
continue to cook and should be removed from the oven
immediately. This pad will also cancel any incorrect
operations. It will not erase programs. It can also be
used to view the details of stored programs.
(see CALL BACK)
6. PROGRAM ‘P’PAD
Activate or set program
7. TIME AND PROGRAM DISPLAY
Shows the time set in minutes and seconds and counts down
in 1 second steps during a cooking cycle.
Also displays error messages and oven temperature.
(PROBLEM SOLVING section 8)
The program display indicates the program number
selected. ‘PP’indicates programming
8. MULTI-STAGE INDICATOR
Indicates stage in multi-stage cooking
9. COLON
When programming the colon will flash to indicate the
time may now be entered.
10. ON/OFF SWITCH
11. ERROR DISPLAY See PROBLEM SOLVING Section 8.
12. QUICK ACCESS PADS
For programs 01-20
13. START
Starts a quick access program
14. STOP
Stops a quick access program

PHUU\ FKHI






























 


Page 8
Error Codes and Diagnostics
The Evolution will identify some of the most common problems by flashing an error message code in
the time display window. (See also Error Light Operation page 17).
These are the error messages and suggestions for repairing them.
1
2
Door not fully shut.
Possible electrical fault
Close door fully.
Door switch inoperative.
1
2
3
No time has been set.
Invalid time has been set.
Invalid program has been
set.
Set a time.
Set a valid time.
Use call-back to check program.
1
2
3
Oven not heating up.
Possible Heater fault.
Possible Sensor fault.
Check heater fuse.
Confirm operation of heater circuit.
(RS units) Check slave heater re-
lay and second supply.
1 Oven Cavity overheating. Confirm heater relay is operating.
(RS units) Check slave heater re-
lay .
1 Oven is not at correct tem-
perature to start program.
Remove food.
Allow oven to reach correct tem-
perature.
Operator Error !!
1 Left Hand
Magnetron overheating. Check air filters. Check location, air inlet tempera-
ture and air filters.
Note : this will lead to condition
shown below. See Page 18
1 Right Hand
Magnetron overheating Check air filters. Check location, air inlet tempera-
ture and air filters.
Note : this will lead to condition
shown below. See Page 18
1
2
Magnetron has over-
heated but has now recov-
ered.
Internal diagnostic fault
Check that magnetron cooling fan
and turntable are working cor-
rectly.
Check installation, air inlet tem-
perature and air filters.
See Page 18
1 Oven control area is over-
heating.
Check air filters.
Check axial fan.
Check installation for hot air in-
take.

Page 9
MAIN FEATURES
1. TRAY HANDLE REST
There is one on each side of the oven for convenient
storage of the tray handle. The handle may be used
to remove hot trays and the rotating cooking carousel
from the oven.
2. AIR OUTLETS
These vents on the rear panel enable air which has
been used to cool internal components to escape. It
will not allow microwave energy to escape into the
environment. They must be kept free from
obstruction.
3. OVEN CAVITY
The cavity is constructed mainly from stainless steel
and vitreous enamelled panel on the door. It must be
kept clean Section 7 CLEANING).
4. COOKING CAROUSEL TRAY AND DISC
The cooking carousel disc is placed on the spindle in
the centre of the oven floor. The cooking carousel
tray fits on top of the disc. These rotate when the
oven is switched on and stop when the door is
opened.
5. AIR INLET FILTERS (LEFT & RIGHT)
Situated at the left and right hand side of the base at
the front. These are part of the ventilation system and
must be kept free of obstruction and cleaned on a
daily basis.
6. DOOR HANDLE
This is a rigid bar which is pulled downwards and
towards you to open
7. GREASE FILTERS (LEFT & RIGHT)
8. MANUAL CONTROLS (See page 11)
9. QUICK ACCESS KEYS
10. ON/OFF SWITCH
When switched ON, the control will light. The fan and
ventilation system will also operate and the rotating
cooking carousel will rotate.
11. RATING PLATE
Found on the rear panel, this states the serial number,
model type, electrical specifications and
manufacturer’s address and telephone number.
12. DOOR
This is a precision-made energy barrier with three
microwave safety interlocks. It must be kept clean
(see CLEANING section ). The door should NOT be
used to support heavy dishes.
13. DOOR SEALS
These ensure a tight seal around the door. They
should be kept clean and checked regularly for signs
of damage. At the first sign of wear they should be
replaced by a Merrychef approved engineer.





















1
6
1
12
5
2
4
3
10
13
11
8
9
7

Page 10
Procedure A - Power Output Test in accordance with
BS EN 60335-2-25:1996 Annex AA
This test is given in the BSI test standard for microwave ovens. It is reproduced below - not so that
you can follow it, but to show you why it is impractical in normal conditions. A simplified procedure,
which gives a good approximation to the BSI power output, is given in Procedure B which follows.
Note: This test can only be carried out on a COLD oven. If the oven has been operating, even for
only a few seconds, the power given will be lower than the oven rating. This test must also
be carried out at a stable voltage - the voltage in most kitchens varies considerably even
within the period of the test. If the oven has been operating, go to Procedure B.
You will need:
A thermometer capable of reading to ±0.1°C.
A cylindrical borosilicate glass container, 190 mm diameter, with a wall
thickness of 3 mm or less.
A calculator.
A set of scales capable of reading 1 kg to an accuracy of ± 1 g.
A glass or plastic stirrer.
A jug capable of holding over 1 litre of water.
WARNING:The Borosilicate Glass container has thin walls and is therefore fragile - take care
not to break it during use.
Method:
A cylindrical container of borosilicate glass is used for the test. It has a maximum thickness of 3 mm,
an external diameter of approximately 190 mm and a height of approximately 90 mm. The mass of
the container is determined.
At the start of the test, the oven and the empty container are at ambient temperature. Potable water
having an initial temperature of 10°C ± 1°C is used for the test. The temperature of the water is
measured immediately before it is poured into the container.
A quantity of 1000 g ± 5 g of water is added to the container and its actual mass obtained. The
container is then immediately placed in the middle of the oven shelf which is in its lowest normal
position. The appliance is supplied at rated voltage and operated at the maximum power setting. The
time for the water temperature to attain 20°C ± 2°C is measured. The oven is then switched off and
the final water temperature is measured within 60s.
Notes:
1. The water is stirred before its temperature is measured.
2. Stirring and measuring devices are to have a low heat capacity.
The microwave power output is calculated from the formula:
4.187 MW(T2-T1) + 0.55 MC(T2-T0)
P =
t
Where P is the microwave power output, in watts;
MW is the mass of the water, in grams;
MC is the mass of the container, in grams;
T0is the ambient temperature, in °C;
T1is the initial temperature of the water, in °C;
T2is the final temperature of the water, in °C;
t is the heating time in seconds, excluding the magnetron filament heat-up time.

Page 11
Procedure B - Simplified Power Test
You will need:
A thermometer capable of reading to ±0.1°C.
A Polypropylene tray approximately 200 mm x 200 mm.
A measuring jug.
A calculator.
Water which is at a temperature of 10°C ± 2°C.
1. Measure 1 litre of cold water into the tray using the measuring jug.
2. Measure the water temperature, and record it as T[s].
3. Place the tray on the turntable in the oven and close the door.
4. Turn the oven on.
5. Set the timer to 1:02.
6. Press the “100%”pad.
7. When the oven bleeps, open the door and remove the tray.
8. Stir the water thoroughly, and measure its temperature. Record this as T[e].
Calculation:
1. T[r] = T[s] - T[e].
2. Power = 70 x T[r]. Power is in Watts.
The power given by the above test should be within ±10% of the rated power.
Procedure C - Power Transformer Test
You will need:
A Digital Multi-meter (D.M.M.)
A Megger or similar resistance meter using 500V d.c.
1. Isolate the oven from the mains supply.
2. Ensure that the High Voltage Capacitor is discharged before commencing work.
3. Remove all connections from the Power Transformer.
4. Using a D.M.M., check the resistance of the windings.
Results should be as follows:
WARNING: High voltages and large currents are present at the secondary winding and
filament winding of the Power Transformer. It is very dangerous to work near this
part when the oven is on. NEVER make any voltage measurements at the High
Voltage circuits, including the magnetron filament.
WARNING: Even when the oven is not cooking, the Power Transformer has High Voltages
present because of the Soft Start circuit. Isolate the oven before testing.
Mains winding (between tags) Approximately 1.1 Ω
High Voltage winding (between tag & chassis) Approximately 60 Ω
Filament winding (between terminals) Less than 1 Ω
Primary winding and chassis Pass if over 10 MΩ
Filament winding and chassis Pass if over 10 MΩ
5. Using a Megger, test the insulation resistance between:
One end of the High Voltage winding is connected to the chassis, so this is not tested.

Page 12
Procedure D - High Voltage Capacitor Test
You will need:
A Digital Multi-meter (D.M.M.)
A Megger or similar resistance meter using 500V d.c.
1. Isolate the oven from the mains supply.
2. Ensure that the High Voltage Capacitor is discharged before commencing work.
3. Remove all connections from the High Voltage Capacitor.
4. Using a D.M.M., check for continuity between the terminals & compare results with table.
5. Using a Megger, test the insulation resistance between the terminals and the case.
WARNING: High voltages and large currents are present at the High Voltage Capacitor. It is very
dangerous to work near this part when the oven is on. NEVER make any voltage
measurements at the High Voltage circuits, including the magnetron filament .
WARNING: Even when the oven is not cooking, the High Voltage Capacitor has High Voltages
present because of the Soft Start circuit. Isolate the oven before testing.
Between Terminals Pass if approximately 10 MΩ
Between Terminals and Case Pass if open circuit
Between Terminals and Case Pass if over 100 MΩ
Procedure E - High Voltage Rectifier Test
You will need:
A Megger or similar resistance meter using 500V d.c.
1. Isolate the oven from the mains supply.
2. Ensure that the High Voltage Capacitor is discharged before commencing work.
3. Remove all connections from the High Voltage Rectifier.
4. Using the Megger, test for continuity in both directions. Compare results with following
table.
WARNING: High voltages and large currents are present at the High Voltage Rectifier. It is very
dangerous to work near this part when the oven is on. NEVER make any voltage
measurements at the High Voltage circuits, including the magnetron filament .
WARNING: Even when the oven is not cooking, the High Voltage Rectifier has High Voltages
present because of the Soft Start circuit. Isolate the oven before testing.
Open Circuit both ways FAIL
Conducts one way only PASS
Short Circuit both ways FAIL
Conducts one way, leaks the other FAIL

Page 13
1 Magnetron cooling fan 310110
2 Magnetron 30Z0851
2A Self Tap Screw 31Z3133
3 Hot air fan 30Z1131
4 Transformer 30Z0931
5 Axial fan 30Z0941
6 Capacitor 30Z0385
7 Diode PCB assembly 11M0325
8 Door switch assembly 11H0008
8A Microswitch 30Z0240
9A Fuse 3 Amp 30Z0940
9B Fuse Holder 30Z0231
10A Fuse 1 Amp 30Z0957
10B Fuse Holder 30Z0231
11A Fuse 10 Amp 30Z0217
11B Fuse Holder 30Z0231
12 Nomex 32Z0121
13A Fuse 3 Amp 30Z0940
13B In-line Fuse Holder 31Z1191
14 Fan start Capacitor —–
15 Filter 30Z0997
16 Temperature sensor 30Z1130
PRINCIPAL COMPONENTS
Right side
3
8A
2
Shown with component
module cover removed
5 12 7 6
4
14
9A
10A 11A
9B
10B
13B
13A
1
15
16
11B
2A
8

Page 14
17A
Left side
17B
18A
18B
19A
19B
17A Fuse 1 Amp 30Z0957
17B Fuse Holder 30Z0231
18A Fuse 1 Amp 30Z0957
18B Fuse Holder 30Z0231
19A Fuse 10 Amp 30Z0217
19B Fuse Holder 30Z0957

Page 15
Top view
Rear view
20A 20B 22A 22B 24A 24B 25
23
21
26
20A Fuse 13 Amp 30Z0168
20B Fuse Holder 30Z0231
21 Turntable motor RMC5055EX
22A Fuse 13 Amp 30Z0168
22B Fuse Holder 30Z0231
23 Interlock Contactor 340504
24A Fuse 25 Amp 31Z0473
24B Fuse Holder 31Z0474
25 Heater Contactor 340504
26 Overheat Safety Stat 30Z1024
2A
3

Page 16
27 Black Handle RBR12852
28 Door Frame 40H0158
29 Door Cover Outer Skin 40H0080
30 Insulation Panel 40H0081
31 Door Reinforcement RMC70722
32 Striker Pin 31Z1214
33 Door Frame (B) MC3055
34 Insulation Wrap 32Z0001
35 Window Screen 40H0082
36 Door Base Silver MC3031KX04
37 Door Cover MC3064
38 Plate - Door Switch MC3056
39 Packing (B) MC3065
40 Internal Centre Panel 40H0146
27
28 29 30
31
32
33 34 35 36
37 38
39
40
OVEN DOOR ASSEMBLY

Page 17
The door on the Evolution oven is monitored by four microswitches. Three of these are used in the
conventional “Primary, Secondary and Monitor”switch arrangement shown below, while the fourth
is a low-voltage switch linked directly to the control circuitry.
Error Light Operation
The “Air Filter Blocked”light and “Service”light are triggered by the internal circuitry. If the magne-
tron overheats, the error code “E:7”or “E:8”is displayed on the front panel, and both the “Air Filter
Blocked”and the “Service”indicators will light. Once the magnetron has cooled sufficiently to allow
the oven to restart, the “Service”light will remain illuminated until the oven is turned off.
This fault may have been triggered by one of the following causes:
- Air inlet on rear of machine being obstructed.
- High air inlet temperature.
- Slow running cooling fan, jammed turntable or broken gearbox
(cooling fan also drives turntable).
- Faulty magnetron overheat ‘stat or associated wiring.
Note that the customer may not have noticed that the oven displayed “E:7” or “E:8” and so
the reported fault may be misleading.
The switches operate as follows:
1 Primary Interlock [ Top Left-Hand ] and Low voltage [ Top Right-Hand ] Switches
Operate simultaneously. Either will cut off the microwave emissions from the oven when the
door is opened: the Primary switch by breaking the mains supply circuit to the transformers,
and the Low-Voltage switch by breaking the relay circuit on the Power / Relay PCB.
2 Monitor [ Bottom Outer ] and Secondary Interlock [ Bottom Inner ] Switches.
Operate simultaneously. The Monitor switch will produce a short circuit across the mains
supply if the Primary interlock switch is faulty, thus blowing the microwave fuse and
rendering the oven inoperative. The Secondary interlock switch will cut off the microwave
emission if all three of the other switches have failed.
Note: If operation of the Monitor switch has caused the Microwave Fuse to blow, the Primary and
Monitor microswitches must be changed, as they may have been damaged by the high
short-circuit currents involved.
Power In
L
N
3 Amp
350ºC Stat Primary
Contactor
coil
Secondary
2
1 Crowbar
2
1
25 amp
Door Interlock Arrangement
Door Interlock Operation

Page 18
INPUT WIRING DETAILS
47 Mains Terminal Block 31Z0477
48 Cable Gland 31Z1070
48A Gland Nut 31Z1082
49 Mains Cable 4 Core 31Z0480
50 Mains Cable 3 Core 31Z0472
2-Phase, Neutral and Earth
49
Green / Yellow
Blue
Brown
Black
48
47 48A
Single Phase
50
Green / Yellow
Blue
Brown
48
47 48A
Note: early models are fitted with a
3-way terminal block

Page 19
41 Membrane Assembly 11H0048
42 On/Off Switch 30Z0503
43 Logic Assembly 11H0045
44 Support Shield 40H0075
45 Relay (PCB) Board 11H0046
46 15 Way Ribbon Connector 11Z0298
Control Panel Assembly
43A Logic Assembly 11H0042
45A Relay (PCB) Board 11H0043
Models with Serial No.s prefix ‘PEV____’only
43
44
45
46
43A
45A
42
41

Page 20
Membrane Panel Circuit
You will need:
A Digital Multi-meter (D.M.M.)
1. Isolate the oven from the mains supply.
2. Remove the Logic Assembly from the
Control Panel Housing.
3. Unplug the membrane “tail”from the Logic
PCB Assy.
4. Using a D.M.M., check for continuity
between the correct terminals when the
pads are pressed.
5. When the panel has been tested, re-
assemble and re-test the control housing.