i have 235 litre electrolux kelvinator double door refrigerator in my home.
Sudarsanan: 235 liters is 8.3 cubic feet, which is about the smallest fridge you can get. So, when you say "double door refrigerator" I presume you don't mean a "side by side". I presume you mean a normal frost free fridge with separate doors for the freezer and fresh food section. Is that correct?
in this model the freezer section works normally but bottom section is not working properly. for every 10 to 15 days when i have open the top (i.e. freezer section) and removes the ice formation on the coil and in drain pipe, refrigerator works for some time. After two weeks the bottom of the fridge fails to cool. I have checked the heater, thermostat, timer and everything works normally.
OK, what I'm hearing you say is that every 10 to 15 days or so, you have to remove the ice that's accumulated from the evaporator area, and after doing that, the fresh food section will cool properly for two weeks or so, and then stop cooling.
If that's correct, then I think the problem is that you have a water logged evaporator housing. The only time water flows into your evaporator pan drain hole is during a defrost cycle. That melt water should stay liquid as it drains away because the further it gets away from the evaporator coil, the warmer the ambient temperature.
If your fridge is anything like my GE 12 cubic foot frost free fridges, there is a styrofoam part under the evaporator pan. Water that runs down the drain hole in that evaporator pan will fall onto a styrofoam part called the "evaporator housing". That evaporator housing will have a sloping ramp on it that directs water to the back of the housing where it drips into a cup that collects it and releases it into a rubber hose that carries it to the receiving pan at the bottom of the fridge.
They make expanded styrofoam by using a "blowing gas" to blow bubbles into the polystyrene as they inject it into the mold. If they use too much blowing gas, then the bubbles that form will be interconnected. And, if they use too much blowing gas when making fridge evaporator housings, then you can have a situation where the fridge evaporator housing is permeable to water. That is, water can flow from bubble to bubble inside the styrofoam evaporator housing until the whole thing is actually full of water.
So, I think what's happening in your fridge is as follows:
While the fridge is operating, the water in your waterlogged evaporator housing gets cold and freezes.
When the defrost cycle starts, the defrost heater starts melting the frost off the evaporator coil. The melt water drips onto the evaporator pan, and heads for the drain.
Once the melt water falls through the drain hole, it lands on the still frozen evaporator housing. That housing is full of very cold ice, and the melt water that falls on it immediately refreezes. As melt water drains away and refreezes on the evaporator housing, the ice gradually backs up and clogs up the evaporator pan drain hole. The result is that your evaporator pan drain hole keeps clogging up with ice, preventing your fridge from defrosting properly.
Without the defrost cycle melt water draining away, it will flow into the vicinity of your evaporator fan, and prevent the fan from operating. If the evaporator fan isn't operating, then you won't get any cold air flowing to either the freezer or fresh food sections of your fridge.
I believe the problem is that a waterlogged evaporator housing is causing your evaporator fan blades to get stuck in ice so the fan doesn't move. I also believe that you're not getting cold air flow into either the freezer or the fresh food section, but the freezer appears to be unaffected only because you open the freezer doon considerably less often than that of the fresh food section. So, the fresh food section warms up more quickly than the freezer does, and so the problem seems to be only with the fresh food section.
Do this: Next time you remove the ice from the freezer, check to see that the evaporator fan is operating when the fridge compressor is running. Then, when the fridge stops working 2 weeks later, open the freezer compartment and listen for the whirring noise of the fan, and feel at the back of the freezer compartment for a draft of cold air. If there's no fan noise, and no draft, your evaporator fan isn't working, and it's prolly cuz the fan blades are encased in ice. That is, frozen defrost cycle melt water that couldn't drain away during the defrost cycle because the drain was clogged by ice. And that problem, in turn, is caused by a water logged evaporator housing.
If my diagnosis is correct, then to fix this fridge, you need to replace the evaporator housing. That is the large styrofoam part between the top of your fresh food section and the freezer floor. Replacing it pretty well means taking out everything between the freezer and the fresh food section. Once you get the old evaporator housing out, you'll need to take the wiring harness off of it and install it on the new evaporator housing. This is the wiring harness that carries power to the fridge light bulb, the defrost heater and thermostat and the evaporator fan. It's not a quick or easy job, and by the time you've got the evaporator housing out, you've got an awful lot to remember about how to put it back in. And, of course, what makes the job harder than others is that the parts you're removing are made of styrofoam and are easily damaged.
You should maybe call an appliance repair shop to get an estimate, but I expect that the cost in material and an appliance repairman's labour would amount to more than the cost of a new 8 cubic foot fridge.