Finding the part that fits
The heater's model name and the size of the connection decide the part. Ducting, outlets and adaptors are sized by diameter in millimetres, from around 300 to over 700, and the inlet on a heater is often a different size from its outlet. Flues are sized by their own, smaller diameter, and cables by the amp rating of the plug and socket they join.
Parts that change what a heater does
A different burner lets some large heaters run on diesel, propane or natural gas, a dual voltage kit lets them run from 110 volt site power, and two-way or four-way outlets split the warm air between several duct runs. A thermostat holds a set temperature and saves fuel. For outdoor heaters, recess kits set a heater flush into a ceiling, and wireless controllers switch or dim it from a distance.
Fitting, gas work and wear parts
Wheel kits, covers, ducting and outlets can usually be fitted by the owner, but a gas burner must be fitted and commissioned by a Gas Safe registered engineer, and any wiring work is for a qualified electrician. Fuel filters clog and heater lamps and elements wear out, so it is worth keeping a spare. A rain cover or cowl keeps water out of a heater or flue that stands outdoors.
