BENSON HEATING LTD G20 I2H, User Instructions

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P
ropane (G31 I
3P
) Cabinet Heater
The minimum allowable pre-purge time requires calculating [BS EN1020:1998 clause 6.38].
To do this only the Carbon Dioxide CO
2
figure needs to be measured.
E.G. on a model 125 the calculated minimum time is = 490.7 / ((300 / CO2) + 2.01)
If the measured CO
2
is 11.2%
Then 300 / 11.2 = 26.79
26.79 + 2.01 = 28.8
Therefore minimum pre-purge time is = 490.7/28.8 =
17.0 seconds
The calculation to be conducted is given below for all models:
Model 100 Minimum pre-purge time = 611.2 / ((300 / CO2) + 2.01)
Model 125 Minimum pre-purge time = 490.7 / ((300 / CO2) + 2.01)
Model 150 Minimum pre-purge time = 399.9 / ((300 / CO2) + 2.01)
Model 200 Minimum pre-purge time = 785.2 / ((300 / CO2) + 2.01)
Model 250 Minimum pre-purge time = 621.5 / ((300 / CO2) + 2.01)
Model 300 Minimum pre-purge time = 515.4 / ((300 / CO2) + 2.01)
Model 400 Minimum pre-purge time = 539.0 / ((300 / CO2) + 2.01)
Model 500 Minimum pre-purge time = 477.3 / ((300 / CO2) + 2.01)
Model 600 Minimum pre-purge time = 458.2 / ((300 / CO2) + 2.01)
Model 700 Minimum pre-purge time = 383.9 / ((300 / CO2) + 2.01)
Model 800 Minimum pre-purge time = 585.9 / ((300 / CO2) + 2.01)
Model 1000 Minimum pre-purge time = 484.0 / ((300 / CO2) + 2.01)
Model 1200 Minimum pre-purge time = 735.4 / ((300 / CO2) + 2.01)
Model 1300 Minimum pre-purge time = 667.5 / ((300 / CO2) + 2.01)
The pre-purge time must then be measured. If the measured pre-purge time is lower
than the calculated time STOP and contact Benson Heating.