extends downwardly to block any further pivoting motion with the lower edge of panel 82 having cleared the lower edge of opening 90 assembly 78 is then pushed back slightly so that bracket 92 is slightly distanced from the lower edge of opening 90 resting the lower surface of heater box 84 on the lower edge of opening 90 allows the upper edge of panel 82 to clear the upper edge of opening 90 as shown in fig1 from the position of fig1 the top edge of panel 82 may be pivoted out of opening 90 so that all of panel 82 is located outside of housing 36 this allows the upward lifting of assembly 78 so that its remaining portions namely heater box 84 and blower 86 may be removed from housing 36 as shown in fig1 another aspect of the invention involves blower support block 94 as shown in fig1 block 94 provides support to the weight of blower 86 at its end which extends away from supply panel 82 without block 94 the attachment of heater box 84 and blower 86 would tend to be stressed which may ultimately result in damage to blower assembly 78 also block 94 is attached to a base pan of housing 36 and stabilizes the physical position.