Technical data

Propane (G31 I

) Tubular Heater

The minimum allowable pre-purge time requires calculating [BS EN1020:1998 clause 6.38].

To do this only the Carbon Dioxide CO

figure needs to be measured.

E.G. on a model 170 the calculated minimum time is = 898.4 / ((300 / CO2) + 2.01)

If the measured CO

is 8.0%

Then 300 / 8.0 = 37.5

37.5 + 2.01 = 39.51

Therefore minimum pre-purge time is = 898.4 / 39.51 = 22.7 seconds

The calculation to be conducted is given below for all models:

Model 40 Minimum pre-purge time = 1597.5 / ((300 / CO2) + 2.01)

Model 70 Minimum pre-purge time = 1203.6 / ((300 / CO2) + 2.01)

Model 100 Minimum pre-purge time = 1007.7 / ((300 / CO2) + 2.01)

Model 135 Minimum pre-purge time = 928.7 / ((300 / CO2) + 2.01)

Model 170 Minimum pre-purge time = 898.4 / ((300 / CO2) + 2.01)

Model 200 Minimum pre-purge time = 879.4 / ((300 / CO2) + 2.01)

Model 250 Minimum pre-purge time = 724.7 / ((300 / CO2) + 2.01)

Model 330 Minimum pre-purge time = 682.8 / ((300 / CO2) + 2.01)

Model 410 Minimum pre-purge time = 661.7 / ((300 / CO2) + 2.01)

Model 490 Minimum pre-purge time = 681.6 / ((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.