Shared Venting gas boiler and water heater

[les jansson]

i did a house the other day and this came up, i drew a blank for a moment . i call out the obvious defect of back drafting on the hot water heater. now here is my question.

on a same fuel flue vent: for example.
a system with a separate hot water heater and boiler is sharing the same vent system, the hot water heater is the last on the flue then the boiler the chimney connection ... so it goes hot water heater - boiler then the chimney connection. is this aloud ,,, i had always thought that largest btu unit has to be the furthest away on the connection hook up . any thoughts on this....

[Billy Stephens]

. any thoughts on this....
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Any Pictures of this? ;)
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[les jansson]

sorry no pics ,,, just wondering about the simple standard theory of the connection ....

[Billy Stephens]

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sorry no pics ,,, just wondering about the simple standard theory of the connection ....
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theory of the connection
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Smallest BTU is Closes to the termination of the vent.
*Does not thwart smaller appliance venting and helps pull the weaker exhaust vapors along and out of the flue pipe.
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[les jansson]

when you say termination do you mean would be the furthest away from connection to chimney?

[Bob Harper]

The reason the code calls for the smaller BTU appliance to enter above the larger has nothing to do with competition within the breaching. It simply allows the smaller appliance to have more vent rise than the larger. Smaller appliances are more prone to backdrafting when the larger appiance is at standby and esp. during summer when the natural draft is weakest.

[Billy Stephens]

when you say termination do you mean would be the furthest away from connection to chimney?
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What Bob Said He's " The Man. "
* or darn close to him.;)
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[les jansson]

thanks for the info