WAN SON CO LTD
Page 82

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7 Elstree Way, Boreham Wood, Hertfordshire.
THERMOBLOC multi-pass warm air heaters in the Wanson range of horizontal and vertically-mounted units are available as oilor gas-fired models that provide free-blowing or ducted air distribution. The air is recirculated or any proportion of fresh air up to 100 per cent can be used. It can be supplied as a warm-air curtain. The company offers a designand-installation service and an after-sales service. And direct gas-fired make-up air equipment is also produced together with thermal fluid heating equipment.
Outputs of the warm air heaters range from 150,000 Btu /hr to 3,500,000 Btu /hr. The small-and-medium range has outputs of 150,000 Btu /hr to 1,300,000 Btu /hr while the outputs of the "large" range vary from 1,700,000 Btu /hr to 3,500,000 Btu /hr.
Models in the former range are produced in eight versions, the forced-draught gas burners of which can burn manufactured or natural gas, burners suitable for LPG being also altailable. They have normal air outputs from 1900 cu ft/min to 16,600 cu ft/min, the temperature rise for all models being 46deg C (82deg F).
Maximum gas oil consumption is from 1.1 gal /hr to 9.4 gal /hr, the maximum consumption of manufactured gas being from 365 cu ft/hr to 3160 cu ft/hr and of natural gas, 183 cu ft /hr to 1580 cu ft/hr. (Town's gas has a calorific value of 500 Btu /cu ft while the calorific value of natural gas is 1000 Btu/cu ft.) The consumption in terms of therms/hr is between 20.4 and 42.
Controls are fully automatic and fail-safe. A time switch and thermostatic control are recommended for the majority of installations. Multiple installations are controlled from a single time switch if a Wanson oil-transfer set is employed.
Models in the range of larger heaters have many features in common with those of the units in the small-and-medium range. Normal air outputs are between 20,600 cu ft/min and 42,500 cu ft/min, the temperature rise for all the models being 45deg C (81deg F). Maximum oil consumption is from 11.8 gal /hr to 26 gat /hr depending on the fuel used, while maximum gas consumption is from 4250 cu ft/hr to 8750 cu ft/hr (town's gas). or from 2125 cu ft/hr to 4375 Cu ft/hr (natural gas), the consumption in therms being from 20.4 units /hr and 42 units/hr.