BENSON HEATING LTD G20 I2H, User Instructions

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Natural Gas (G20 I
2H
) Cabinet Heater
The minimum allowable pre-purge time requires calculating [BS EN1020:1998 clause 6.38].
To do this only Carbon Dioxide CO
2
figure needs to be measured.
E.G. on a model 300 the calculated minimum time is = 203.6 / ((100 / CO2) + 1)
If the measured CO
2
is 9.7%
Then 100 / 9.7 = 10.3
10.3 + 1 = 11.3
Therefore minimum pre-purge time is = 203.6 / 11.3 =
18.0 seconds
The calculation to be conducted is given below for all models:
Model 100 Minimum pre-purge time = 241.4 / ((100 / CO2) + 1)
Model 125 Minimum pre-purge time = 193.8 / ((100 / CO2) + 1)
Model 150 Minimum pre-purge time = 157.9 / ((100 / CO2) + 1)
Model 200 Minimum pre-purge time = 310.1 / ((100 / CO2) + 1)
Model 250 Minimum pre-purge time = 245.5 / ((100 / CO2) + 1)
Model 300 Minimum pre-purge time = 203.6 / ((100 / CO2) + 1)
Model 400 Minimum pre-purge time = 212.9 / ((100 / CO2) + 1)
Model 500 Minimum pre-purge time = 188.5 / ((100 / CO2) + 1)
Model 600 Minimum pre-purge time = 181.0 / ((100 / CO2) + 1)
Model 700 Minimum pre-purge time = 151.6 / ((100 / CO2) + 1)
Model 800 Minimum pre-purge time = 231.4 / ((100 / CO2) + 1)
Model 1000 Minimum pre-purge time = 191.2 / ((100 / CO2) + 1)
Model 1200 Minimum pre-purge time = 293.2 / ((100 / CO2) + 1)
Model 1300 Minimum pre-purge time = 263.7 / ((100 / CO2) + 1)
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
.