Book - School of Science and Technology

132 Electrical storage heatingCasingCore blocksInsulationElementsOutlet grilleReturn air under(a)Fan boxMixing damper(core output &return air)(b)Figure 5.5 (a) Storage fan heater components and (b) modern pedestal type (Dimplex)evening `top-up'. This may take the form of either an additional element or of some meanswhereby the normal controls to one or more of the core elements may be overridden. Thepurpose in each case is to provide instant heat output which is quite independent of theoff-peak charged supply.Floor warmingAn important part of the `equipment' required for floor warming is the storage medium ±the floor structure itself. The remainder comprises the resistance elements which are laidin situ within that structure. Output is about 50% convective.The total length of cable elements must be such as to produce the required loading andone or more parallel circuits may be needed. Cables are laid in a grid-iron pattern at