Venting

johny

Could somebody please explain the different types of vents,what is type B vent,type L vent,triple wall vent.And what is all fuel vent or chimney.Which ones are used with gas,which ones with oil.Any response greatly appreciated.Thanks

Unknown

Venting

Type "B" Vent is a double wall vent for use with low temperature situations such as gas. It consists of double wall construction reduced clearance to combustible materials (1"). The inner wall is usually aluminum to resist corrosion and the outer wall is galvanized. As compared to what used to be called type "C" which is single wall which is usually 26 gauge galvanized it has a clearance to combustible of 6" unless used on a conversion burner type system then it is 9". Type "B" can not be used on conversion burners.

Type "L" is similar to Type "B" but features an inner pipe of stainless steel. The type "L" vent is intended for venting higher temperature flue gases generated by certain types of oil fired equipment.

The type "L" vent could be used in place of Type "B" gas vent provided the appropriate installation requirements are met. You can not however vent oil fired equipment into a type "B" vent.

There is also a Type "BW" vent which is oval shaped it was designed and tested for use in through the stud space venting of gas wall furnaces. It is always oval shaped.

All fuel vents or factory built metal chimneys and also chimney liners each have their own particular requirements. You would need to read manufacturers specs on each one to know what they can be used for.

For all gas equipment today you have to check to see which category it falls into. For example all Category I vents are typicaly natural draft systems vented into single wall or Type "B". In some cases they can be used with "FAn Assisted equipment". The other category's II, III and IV are special venting and manufactureres instructions outline how each piece of equipment is to be vented.

One last thing is that Type"B" vents can not be used on Power Vented applications where the vent would be at positive pressure as it will leak into the space. Anything on the suction side of the vent is okay but on the pressure side it must be sealed. A good way to test is to bring the system on with out the fuel supply turned on and with a mixture of soap and water soap the joints of the flue, they should not bubble.

Hope this helps, by the way I have some manuals and guides on venting which are availabe for ordering from our catalog.