1200w

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1. Waffle Irons
The waffle baker has reversible Teflon-coated grids, and is controlled by a thermostat which allows a temperature range of from 210° to 470°F. It is rated at 1200W, 120V ac, which is a typical specification for waffle irons. If the unit is "dead," that is, if it will not heat at all, begin a continuity test with an ohmmeter from one of the male plugs on the line cord step-by-step through the element, thermostat, and back to the other male plug. If the thermostat and heating element both have continuity through them, check for loose or broken connections within the top and bottom shells and in the line cord itself. If the problem is one of not cooking the waffles (or burning them), the thermostat may have to be replaced. First, however, try adjusting the thermostat. Remove the bottom grid, and loosen the set screw on the stop arm. Replace the grid, and determine the temperature with a thermocouple or surface thermometer placed in the center of the grid. With a thermocouple, the unit must be closed for an accurate reading. With a surface thermometer, the unit must be open; therefore, the temperature reading will not corespond with the name-plate specification. Set the control knob at "3" and take a temperature reading after about 6 cycles or when the reading has stabilized. The cycles can be observed by the use of a wattmeter or by the on-off indication of the signal light. The temperature reading at "3" with a thermocouple should be 320-340°F. A thermometer reading should be 240-260°F. If the temperature reading is outside this range, turn the control knob accordingly to obtain a reading within this range. This may take several cycles. Remove the knob insert with a sharp tool for access to the screw securing the knob to the shaft. Then remove the knob from the shaft without moving the shaft and reset the knob at the "3" position. With the top arm in the vertical position, tighten the set screw of the stop arm using Loc-Tite as a sealant. The stop arm limits the rotation of the control knob within range of the name or temperature indicator plate. If a thermostat is replaced or a control knob accidentally removed, a starting position must be determined. To do this, loosen the set screw in the stop arm and rotate the control shaft until an on-off point is found. Install the control knob at the 210°F point and adjust the thermostat as described above. If the heating element is open, you will have to disassemble the waffle baker and replace the element. First, remove the bottom grid. Next, bend the retaining tabs and remove the element shield. Note the position of the control knob before disturbing it. Then straighten the retaining tabs of the element case and lift the element case up and out of the shell. Be careful not to move the control shaft. Note that the element case is slotted to allow the retaining tab to pass. Remove the element from the terminals and hooks. When replacing the element, stretch it so that the coils are evenly spaced for even heat classification. Replace any element hooks which may be cracked or broken. Position the insulating washers at terminals properly to prevent shorting. The upper element must be placed so the glow can be seen through the lens of the signal light. To replace the thermostat, remove the element case (see the preceding paragraph for element disassembly), then the element lead to top shell and the thermostat lead at cord terminal pin. The element case with thermostat can now be removed as an assembly. Pry and slide the outer housing up and out of the case. Remove the insulation pads and the thermostat lead at the element terminal. Replace the nuts on these terminals to prevent damage to insulating washers. Remove the stop arm. Now turn element case on its back and remove the control shaft by turning it clockwise. Catch the loose washer at the thermostat end of the control shaft. Turn the element case over and lift out the thermostat along with the inner housing. Remove the thermostat from inner housing. A silicone lubricant can be used on the threads of the control shaft for ease of operation.
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2. Table - Range
Table ranges are often used in apartments where full-scale gas or electric ranges are not practical. As you can see from the illustration, the units are extremely simple, consisting of a plug, a thermostat, and a heating element. Some models have two or more elements, and each element is controlled by its own thermostat. Typical ratings are 500- 1200W at 120V ac. The first phase of troubleshooting consists of testing the range for short circuits. Be sure it is unplugged When making these and other continuity checks, disconnect one lead of the component under test. This procedure isolates the component from the rest of the circuit and assures accurate results. Turn all controls to the off position. Now using a continuity tester, attach one lead to one prong of the cord and touch the other lead to exposed metal parts such as: the stove body, top deck, and front panel. Repeat the test on the other prong of the cord. No continuity should be read. Any reading here will indicate a direct short to the case. Attach one tester lead to each prong of the cord. A reading here will indicate a short in the wiring, or a defective power switch on the unit. The next step is to test for opens. With the leads of the continuity tester touching each prong of the attachment cord and all controls turned to off position (full counterclockwise), there should be no measurable continuity. Now rotate the controls one at a time in a clockwise direction. Continuity should be measured approximately midway between off and lo and throughout the entire span of each dial to hi. No continuity means an open circuit within the unit. Check the thermostat, wiring, and burner. Intermittent readings usually indicate a faulty thermostat. If continuity appears too soon or too late, the thermostat needs calibration. To calibrate the thermostat, employ the unit and turn all controls off Connect the leads of a continuity tester to each prong of the attachment cord. Rotate control knob clockwise midway between off and lo and remove the control knob. (It pulls straight off.) The thermostat-adjusting screw is a slotted head screw, located inside the center of the thermostat stem. Hold the stem and turn the screw. If continuity is measured too soon, turn the adjustment screw clockwise until circuit breaks. Turn counterclockwise if continuity appears later. After the adjustment is complete, rotate the control post completely counterclockwise and replace the control knob. Off should be at the top of the dial. The final test is to turn all controls to the highest heat position and allow the unit to operate for 45 minutes at full rated voltage. During this period, none of the controls can cycle. After 45 minutes, rotate control knobs counterclockwise and note where the controls start cycling. Cycling should occur when the controls are somewhere near midrange. Most service operations can be performed through openings in the top deck after the drip pan is removed. Tilt back the element and remove the screw. Snap out the drip pan using a knife blade or screwdriver. When the pan is removed, the element can be pulled out and injected along with the wiring and the thermostat. To replace the drip pan, simply tilt back the heating element, snap pan in place—and install the screw. The heating element can be removed by taking out the two terminal screws which secure the lead wires. NOTE: The terminal block is replaced separately if this part is damaged. To remove the thermostat, first remove the drip pan, control knob, and felt washer. Hold the thermostat from the inside and take out the screw for the heating element and retaining plate. Then remove the slot-head screw in front of the thermostat control post. Detach the lead wires and lift the thermostat through the burner opening. Thermostats should be matched to the heating elements and control knobs in accordance with the temperature of the element—some units have both high- and low-temperature burners. Note: Do not overlook the steel spacers which must be installed with a replacement thermostat. The attachment cord may require attention after long use. To replace it, first remove the drip pan, then the two porcelain wire-nut connectors and tape from the inside of the unit. Snap the strain-relief bushing out from the rear of the body and pull the cord out through the body. CAUTION: Only porcelain wire-nuts and high-heat tape should be used when making connections inside of these units. Temperatures are high. The top deck is serviced by removing the drip pans and the screws along the top rear edge of the back of the unit. Next remove the two indicator screws located above the control knobs. The deck is free and can be lifted clear.
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3. Electric Rotisserie
In this category fall many of the broiler / baker / toaster ovens now on the market. Electrically these units consist of a thermostat and one or two heating elements. Some of them contain a motor to rotate a spit as well. The rotisserie may encompasses a timer in addition to a thermostat and two heating elements. You should note that all current must pass through the timer—hence the timer must be on in order for any portion of the rotisserie to function. A bake button controls the lower element and a grill button controls the upper element. A rotis button operates the drive motor and upper element, and the temperature knob controls the thermostat. Consider a unit rated at 115V, 1500W. it draws 1200W on the lower element and 1350W on the upper element. Begin by making an operational test. Remove the griddle and tray so that the elements can be observed. Place an oven thermometer on the rack in the center of the oven. Then close the front and lid doors. Turn the timer on and engage the bake button. Set the temperature control knob to 300°F. The indicator light should go on to indicate power to the element. When the light goes off, the cycle is completed. After several cycles, the temperature reading should be between 275° and 320°F. There can be an overshoot of 100° on the first cycle. If an adjustment is required, turn the control knob to the correct temperature range, loosen the set screw in the knob, and position the knob at 300°F. As a double-check, make an additional temperature test at 450°F. To disassemble, pull or pry off the timer knob. Then loosen the set screw and remove temperature control knob. The nameplate is secured by a screw located under the timer knob. Take out the screw securing the thermostat to the side panel. It is located on the right side of the temperature control shaft. Remove the 5 screws holding the left side panel to the chassis. Pry the panel off from the back so as to slide off the temperature control shaft in the front. The Hoover rotisserie employs a manual timer with an electrical switch. The switch can be tested with an ohmmeter, or it can be eliminated from the circuit by bypassing it with a jumper wire. The drive motor in the rotisserie shown (and in many others) is replaced as a unit. This motor should not require any additional lubricant. If a lubricant is added it must have a high temperature range due to the heat from the oven. Use one of the silicone greases in this area. To replace the thermostat, disconnect the lead wires and remove the thermostat from its mounting bracket. Save the old control shaft since it is not a part of the replacement thermostat. Install the thermostat with metal-to-metal contact on the mounting bracket. Mica washers are used behind the bracket. Place the control shaft into the thermostat. Calibration is now lost. Install the left side panel. With the timer on and the Bake button in, connect an ohmmeter or wattmeter to the cord. Turn the control shaft until the on-off positions are established. Then install the temperature control knob at the lowest setting and proceed with temperature test to calibrate the stat. The elements can be removed by disconnecting the wiring and sliding the elements off of their supports. Test with a wattmeter per specifications given above. Inspect the insulators for cracking, chipping, or other signs of deterioration, Hoover is a bit unusual since the company offers replacement chassis assemblies complete with sides, bottom, back panel, and all riveted parts. Most small-appliance makers do not supply major structural parts.
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4. Electric Heaters
The simplest and most popular electric heater is a heating coil connected to a line cord. A more'complicated type is shown in the exploded view in Fig. 5-5. This is a room heater with a two-speed fan and automatic temperature control. It uses two finned heating elements and a switch for a selection of one element or two. A control lever regulates the temperature. When set to the extreme left, the unit is off. A slight movement to the right turns on a light to indicate the unit will go on when the thermostat calls for heat. The unit automatically maintains the desired temperature in the area it is capable of heating. Many models similar to the one shown have a tip-over switch to automatically shut off the heat if the unit is tilted more than 30 degrees from the upright position. The fan operates at 2100 and 2700 rpm. The unit is rated at 1650- 1200W, 120V, 60 Hz, and delivers 5600 BTU / hr. Thermostat Calibration Although many space heaters have nonadjustable thermostats, the thermostat used in this particular unit is adjustable. The thermostat uses a bimetal leaf with two adjusting screws. Access by removing the two expansion-clip plugs located underneath the shell. The thermostat also has a back contact to activate the light. This contact is nonadjustable. The adjusting screws have a slotted head to accept a screwdriver. When making an adjustment, turn the adjusting screw only a quarter turn at a time and then remove the screwdriver as the slight pressure of the tool will give a false reading. Use a continuity tester, VOM or wattmeter when making any adjustment to the thermostat. To adjust for room temperature, slide the temperature-control knob slowly to the right until the circuit is complete. The temperature point on the faceplate should be within 10° below room temperature. If the variation is more than 10° below room temperature, set the control knob within this range on the faceplate and turn the thermostat adjustment screw clockwise to open the circuit. Should the control knob go past room temperature on the faceplate, turn the thermostat adjustment screw counterclockwise to move the adjustment down to room temperature. After each adjustment, return the control knob to the off position and repeat the circuit test. Make the differential adjustment after the room-temperature adjustment. (See Fig. 5-6.) This adjustment varies the time lag of the bimetal leaf. The wider the gap, the longer it will take for the bimetal leaf to close the circuit. Move the control knob to the right and left so the thermostat contacts just open and close. Note the temperature difference on the faceplate between the on and off positions. This is the differential. Turn the differential adjustment a quarter turn at a time to limit the differential to approximately 5°. Turning the screw clockwise decreases the differential; counterclockwise increases it. Do not adjust the differential too small. This could cause a continuous closed contact or erratic on-off cycling. The back contact for the light can be tested with a VOM at the thermostat terminal leads. Servicing The Units To disassemble, remove the two screws securing the nameplate to the shell. Pull the temperature control knob from control lever. Some lubricant may be required so the knob slides freely. Remove the control lever; it is secured by a nut. Note the flat on the shaft for positioning the control lever. Next, take out the two screws located directly above and below the control shaft. The screws on each side should not be removed. Remove the screws securing both switches to the shell and the outer screws securing the rear cover to the shell. The rear cover with all component parts can now be lifted away from the shell for replacement of parts and testing. To replace the thermostat, remove the two screws from each side of control shaft which secure the thermostat to the light bracket. Disconnect the wires from thermostat. The switches require special consideration. With the element switch on low, the 1150W element circuit is complete and the switch is open. Turning the switch to high adds the 450W element. The fan switch employs a resistor to reduce the fan motor rpm. On high the switch is closed. Both switches can be tested with a VOM. A complete circuit indicates a closed switch. If the switches are not isolated from the circuit, a resistance reading may appear on an open switch. During assembly the switches are positioned in the shell with the terminals towards the bottom. The motor can be electrically tested between the motor-lead connection on the fan switch and the splice lead at the element switch. Replace the motor as an assembly (less fan). Remember to oil the bearing felts when servicing the unit. The 1150W element (upper element) is used whenever the heat is on. The 450W element (lower element) is added when the element switch is on high. The elements are marked on the end for identification. Remove as follows: a. Disconnect the wires from elements. b.  Remove the element retainer and slide the elements out. c. Check for broken or cracked ceramic insulators. d.  Use Silastic 732 RTV or other plastic sealer on the element ends and ceramic insulators to prevent rotation and a vibration rattle. The tip-over switch is a safety switch used to open the heating circuit when the unit is tilted over 30 degrees from the vertical. The pendulum on the switch must be free to move and the contacts must close when the pendulum is in the upright position. Troubleshooting No heat means an open in the element, thermostat, or tip-over switch. Make individual continuity checks. If only the low-heat function operates, check the low-heat element and switch. No light would lead one to suspect the lamp (filament and socket) and the back contact on the thermostat. A dead fan involves the motor or fan switch. The former may have an electrical fault or it may be the victim of seized bearings. If the room temperature is too low, look to the thermostat adjustments. The stat may be adjusted too low or the differential may be too wide. A dead fan can also be the culprit. Of course, a low-heat complaint assumes that the room is not too large for the heater. Too high a room temperature means that the thermostat is too high or that the differential is too small. Noise can originate in loose motor mounts, contact between the fan and shell, or a loose element.
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