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05-07-2015, 03:56 PM #1
Water heater metal flue shared with hi-eff furnace plastic?
I had never seen this until today...is this acceptable? I wouldn't think so...wondering if the plastic will melt...but it was ok currently. The metal pipe is from a gas water heater, and the right one is a high efficiency furnace.
Positive pressure vents such as a hi-eff furnace should not be combined with a natural draft item such as the water heater...correct? If so, this vent is done incorrectly and the two should be separated. Comments welcomed.
Similar Threads:Last edited by Dave Rose; 05-07-2015 at 04:42 PM. Reason: Added 2nd paragraph for clarity
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05-07-2015, 04:41 PM #2
Re: Water heater metal flue shared with hi-eff furnace plastic?
The problem is likely not going to be the plastic venting for the furnace, but rather that it is a positive pressure vent and the water heater and existing vent is (should be) a Type B gas vent for gravity venting (atmospheric pressure only).
Type B gas vents are not suitable for positive pressure use.
That may be your biggest issue, others here will likely add more that I am not including because ... correct the positive venting into a Type B gas vent and the other issues may also go away.
Just saying ...
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05-07-2015, 04:44 PM #3
Re: Water heater metal flue shared with hi-eff furnace plastic?
That is type 'B' vent going into the ceiling which is approved for CAT I venting only, such as the WH. That furnace vent generates positive vent pressure, which is CAT III or IV. No, it is grossly illegal! Also, that storm collar could be hiding what is going on with the listed ceiling support/ firestop or lack thereof. The water stains are a red flag due to heavy flue gas condensation that has probably rotted out the B-vent. They must be vented separately but that B-vent probably is ruined. Would need to be reduced to 4" anyway. More pics?
Keep the fire in the fireplace.
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05-07-2015, 07:20 PM #4
Re: Water heater metal flue shared with hi-eff furnace plastic?
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05-07-2015, 08:03 PM #5
Re: Water heater metal flue shared with hi-eff furnace plastic?
thanks all, good input. I will make appropriate comments.
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05-08-2015, 05:08 AM #6
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05-08-2015, 06:03 AM #7
Re: Water heater metal flue shared with hi-eff furnace plastic?
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