Changing vent size...

[ironroad 9c1]

Anyone think there would be anything wrong with going up one size in part of the vent pipe ? My heater has a 5 inch vent pipe and its almost impossible to find 5 inch type b piping anywhere local, only thing I found was single wall , and then I couldn't find a cap and flashing, so I got a 5-6 inch expander and got some 6 inch type b pipe, flashing and storm collar and cap.

 

[hidollartoys]

Check with the manufacturer and see if that is ok.

 

[kbs2244]

It will depend on how much your unit depends on the stack for draft.
You will be loseing draft volocity, and adding turbalance at the joint, if you go bigger.
Where have you been looking?
% inch shouldn't be that hard to find.
I have even seen it in some of the big box stores.
For sure at a HAVC supply house.

 

[ironroad 9c1]

I found 5 inch single wall, but no roof flashing or cover.or type b pipe period.

 

[mmg440]

If you have a near vertical run with very little or no bends I would think 1 inch larger then to outlet would be fine. To be 100% sure you could check with manufacture of your heater. Might even find online. The B pipe will have more draft then a masonry flue would. I would run it.

 

[ironroad 9c1]

Well I only have to go straight up about 3-4 feet. and I don't see how this type B has any more flow that anything else, its closed at the top.only thing i see where it might help is the extra 1 inch around the inner pipe for insulation.