is connected to drain pipe 46 which is routed to waste throughout its traverse through the cold space the meltage is heated by thermal communication with hot gas tube 48 40 and 14 fig3 is a cross section at a a of fig2 showing the trough portion 42 connected at point 50 to hot gas tube 40 with an open space 43 which allows any possible overspill from trough 42 to freely occur in the situation that drain pipe 46 has been plugged with dirt or ice the meltage flowing through outlet fitting 20 through trough 42 to drain pipe 46 will gradually fill and therefore back up into said drain pipe when enough meltage has frozen and accumulated then subsequent meltage from defrosting coil 2 will overspill the open portion 43 of trough 42 and will drip upon the floor and freeze no build up of ice to the point where the closing of outlet 21 of fitting 20 can occur because the entire portion of trough 42 is warmed above freezing by thermal contact with hot gas tube 40 therefore in the situation that drain line 44 has been plugged personnel operating in the freezer in the routine performance of their duties of withdrawing and stacking merchandise will be altered to the drain problem and will in turn alert the maintenance group so that corrective measures can be instituted fig4 shows a drain pan 8 like that of fig2 with hot gas inlet 14 connected to hot gas tubes 48 and 40 and drain line 46 and supplementary drain tube 44 connected to outlet fitting 20 outlet fitting 20 is fashioned with holes 56 located in the upper portion.