furnace and water heater exhaust pbm

Old 10-18-02, 05:18 AM
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Angry furnace and water heater exhaust pbm


I bought a house about 5 months ago and this has been our first chance to use the furnace. We noticed that each time the furnace had to run, the pilot would end up going out on the Hot Water Tank.

My theory is that the exhaust from the furnace is going down the exhaust pipe for the hot water tank and either blowing out, or more likely snuffing out the pilot from oxygen deprivation.

I see a seperate exhaust pipe for the furnace and hot water heater, and they both go into the chimey, but not idea where.

Even after the pilot on the water tank had been out for several hours, after the furnace kicked on, the exhaust pipe for the hot water tank was getting hot - hence my theory.

Is there a backflow or some other way to fix this problem??
Old 10-18-02, 01:26 PM
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Carbon Monoxide poisoning

If the flue is getting warm when the water heater is not on, then the exhaust fumes from the furnace are re-entering this area. This requires immediate attention.

The most likely cause for this is blockage inside your chimney, such as a bird or squirrel. Sometimes the flue is inserted too far into the chimney. As the gases exit the flue it hits the wall or lining of the chimney and the force of the gases coming out causes the gases to blow back towards the water heater's flue. And a siphon affect is initiated. Another cause is the room for these appliances is too air tight.

In either case, this requires immediate attention and you should have a professional service person look at and resolve this.

This is a perfect example why we should have carbon monoxide detectors in our homes.

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