Dripping sound in HWH exhaust pipe HELP
we have a hot water heater in the garage – virtually new 75Gal. that is directly beneath an upstairs bedroom. The exhaust from the HWH vents at a 45 from the top of the heater to the hole in the ceiling, then (presumably) goes straight up through to the roof. well, when the HWH is running, we can hear a constant dripping in the bedroom coming from the wall. There are no leaks, or other issues, and the sound itself can drive someone who is trying to sleep nuts. its always been like this since we bought the house… aside from tearing open the walls, and trying to find where the condensation is building up, does anyone have any suggestions on what we can do to remedy? <!—-> <!—->
thanks for the help,<!—->
-mike. <!—->
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Replies
So simply a drip? As opposed to a drip and a sizzle? Sizzle means that condensation in the flue pipe is falling back to the HWH, often to the hot flame spreader above the flame. I've heard that on filling a HWH with 38F water and also if a HUGE flow filled the HWH with 40-50F water.
Simply a drip? The duct pipes may have been run backwards. Some people think the male end goes up to minimize friction drag for the gas stream. Not. The male end goes down, so any condensation drips stay in the flue pipe. This is critical for wood-stove pipe - you don't want creosote drips on your living room carpet. So stove installers learn that earlier than other flue-pipe installers.
If case the gods are with you - check for bird-nest, clogged spark arrestor, and too-short a flue run. Otherwise, yes, you are going to be digging into the walls.
You may also have too many bends in that flue run for the available draft. 45s and especially 90s add large pressure drops to a flue run. If it is not a straight run, repost with the particulars.
Are you sure it's a drip, or is it the flue pipe expanding and contracting with heat? It's not at all unusual for flues and similar ducts to go "tick, tick, tick" as they heat up or cool off. What you're hearing is the duct sliding against a mount or some such.
If it really is dripping it would likely be condensation from the flue gasses, but this would be unlikely (especially in warm weather) except in a high-efficiency setup (> 85% efficiency), and there a plastic flue should be used (since the condensed water vapor is highly corrosive).
thats true... its so rythmical that i guess i just didn't even consider that... guess there is no way around that one
Drips will usually have a slightly irregular pattern -- drip-drip, drip-drip, drip-drip, eg, vs equally spaced clicks.