I have model #FFU13MHW2 upright freezer & can not figure out how I am supposed to defrost as it has no drain hole on the bottom panel

SOURCE: kenmore upright freezer

Usually you shouldn't have any ice on the bottom unless something spilled etc. and froze. How all this basically works is... the cooling coils are where the brrrrr cold comes from but that causes frost/ice on the coils. About every 12 hours a little clock timer that runs continuously turns off the compressor and evap. fan then turns on a heating element that's under the coils. This heat runs till the defrost t-stat (clipped on the upper coil area) determines it's been warm enough that all the ice should have melted and turns off the defrost heater. Then everything returns to normal cooling until the next cycle starts again. As for the melted ice, that water drips into sort of a channel that funnels the water to the drain hole (should be just under the coil area). From there it goes down a tube to a holding pan near the compressor area in the bottom of the unit where heat from the compressor,etc. causes it to evaporate into the air long before the next defrost cycle puts more water into it. Sooo... check that your drain hole is open by pouring hot water down it and see if it flows fast out to the holding pan. Clean as needed.

SOURCE: My freezer's defrost systems runs constantly

i dont think so i would look at the compressor kicking out on thermal overload or a faulty thermostat thermostats have two settings cut in cut out your cut in could be bad and not turning the compressor on till the temp reaches melting temps now if your hearing a click buzz then you need to look at the compressor and make sure the compressor fan is running but its not a defrost promblem

SOURCE: ICE BUILDUP ON BOTTOM OF FREEZER, DRAIN HOLE FROZEN

There is normally a small filiament of metal which is attached to the defrost element and conducts heat down the drainpipe preventing ice build up. You can pour some boiling water onto this area and even wriggle a piece of plastic tubing down the drain pipe to dislodge any blockage. For future prevention, you can attach a piece of copper wire around the defrost element (in the absence of the original filiament) and extend it down the drainpiple