The chip heater consisted of a cylindrical unit with a fire box and flue through which a water pipe was run. Water was drawn from a cold water tank, circulated through the fire box and when heated was drawn off to the area where it was used typically in a bath or shower.
The fire box was relatively small and fed by newspaper, with pine cones, small twigs and chips from the wood heap. There often was an ash box under the fire box which also allowed air under the fire as well as various dampers in the flue. The use of chips from the wood pile gave the heater its name – chip heater.
Water was run in at a trickle otherwise it did not get very hot. The rate of combustion was controlled by the flues and the ash box. With lots of fuel and the flues open the water could be quickly boiled which was not a desirable result. With practice the correct combination of fuel, flue settings and water flow could result in a decent hot shower or bath in about 20 min.
The original idea surely must be derived from vertical steam boilers. Professor Miles Lewis notes that “the 'instantaneous water heaters', which were being sold by Douglas & Sons of Melbourne by 1888 were probably of this sort. In 1892 the Melbourne iron founder Angus McLean was advertising as the sole proprietor and manufacturer (presumably for Victoria) of Fischer's Patent Bath Heater, which could be heated with wood in three minutes at the cost of one farthing.”
Catalogues from the National Radiator Company (Hull, United Kingdom) from 1913 and 1919 which were marketed in Australia do not show chip heaters suggesting that the chip heater was local innovation.
The Australian producer “Metters” have a variety of chip heaters in their 1936 catalogue including oil and kerosene powered chip heaters as well as four varieties of chip heater. Metters claimed a flow of 2 gallons of “very hot water” per minute.
Metters Ltd 1936 Metters' bath heater and hot water service : sectional catalogue, Metters Ltd.
Oliver, Julie. The Australian home beautiful: from Hills hoist to high rise, McMahon's Point, N.S.W. Home Beautiful, 1999.
Postings on the NSW Heritage Office Heritage Advisors Discussion Group by Peter Benkendorff, David Beauchamp, Susan Duyker, Elizabeth Roberts and Peter Woods, April 2007.
Posting on Engineering Heritage discussion group by Professor Miles Lewis 26/04/2007