Gas water heater vent too short?

4456 Views 6 Replies 4 Participants Last post by yuri, May 4, 2016

Ginny28

Discussion Starter · May 3, 2016

I had a vent that stood about 3' above my roof that used to service both my furnace and gas hot water heater. I had the furnace changed several years back with it's own venting. I just had my roof redone and asked if he could cut down the vent pipe and change out the ugly, old cap. I didn't question much as I thought he would know what the height requirements were. I was surprised when he cut the vent within 1" of the roof line and put a 4" standard flue on it. I envisioned a shorter vent with a newer cap. The new vent is below the highest point of the roof ridge. The roof ridge is about 1 1/2 feet away.

I know it vents as I've lit a match, blown it out, and the smoke goes up the vent.

I'm also concerned about snow as I live in Michigan and the vent would certainly be covered in the winter, although I assume the snow around it would melt?

Are there specific guidelines on how high a lone gas water heater vent should be?

I like the looks of the new vent, but I want to be safe and be within building requirements. Thanks.

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yuri

· #2 · May 3, 2016 (Edited)

That sounds wrong and could give you CO poisoning as there is not enough heat to melt the snow.

You need a licensed gas fitter or chimney Pro to look up the rules in the gas code book. Here is a link with some basic rules but it does depend on the slope of the roof and your climate and type of chimney. Generally in my area it needs to be 3 feet above the top of the peaked roof unless the nearest part of the sloped roof is 6 feet away. It still needs to be at least 3 feet above the roof where it leaves. It is never good to be below a sloped roof as you can get swirling winds and downdrafts in the chimney and CO poisoning. Get a Pro to do it properly.

http://www.checkthishouse.com/72/chimney-flue-furnace-water-heater-venting.html

http://www.checkthishouse.com/2418/gas-appliance-chimney-placement-and-termination.html

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yuri

· #7 · May 4, 2016 (Edited)

Good Pics.

Notice the fine print: Height may need to be increased to provide sufficient draft.

It is always better to be a bit longer. The longer the chimney the more draft it creates. Especially if you have roofs with 2 slopes/valleys or big trees nearby. You can get swirling winds and problems. I would have it redone to it's original height.

You should also have 2 new CO detectors. 1 in the basement on the stairs going up as smoke/CO rises and 1 near your bedroom.

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