Propane/gas water heater & carbon monoxide

Old 02-08-15, 09:19 PM
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Propane/gas water heater & carbon monoxide

We purchased our first home a year ago. We have recently heard clanking sounds. I know some are from the hot heater and the really hard water we have here having left lime. Having JUST learned this, I think it's too late to bleed it. Is this true?? Is there some maintenance we can do??

My biggest worry is that wednesday I came home and the carbon monoxide monitor on the lower level was going off. I changed the battery and it ceased. Two nights later (Friday night) I came home and both carbon monoxide monitors on the upper and lower floors were going off. I opened the doors and called 911. The fire dept came and said our monitors were 11 years old and they didn't find any reading of carbon monoxide anywhere in the house (including in the basement with the water heater). We got new monitors yesterday. So far, so good.

My question is: can the lime in the heater somehow cause problems with the mechanism that vents out the home? We've been here since 11/28/13 and have never touched the hot water heater. I'm just concerned.

Also the clunking is really REALLY loud at times. It has shaken the floor above once or twice. Again..., worry? Or just annoying??

Thanks for any feedback!!
Old 02-08-15, 09:49 PM
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Welcome to the forums.

I'm not the plumbing pro but just making a few observations.

The minerals built up in the tank have no bearing on the flue system and exhaust venting.
I'm concerned that both CO detectors were activated. That might suggest a flue/chimney blockage of some type.

Can't help you on the clanging noise. The pro's will be by later.
Old 02-09-15, 12:27 AM
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Residential CO detectors have a useful life of about five years at best. Since yours are more than twice that age you do need to replace them.

Water heaters used with hard water have a lesser lifespan than heaters used with softened or naturally soft water. Periodic flushing of the tank will usually prolong the life but if it hasn't been done on a regular basis from the beginning flushing an old heater may cause it to leak in a very short time. Since the "average" lifespan of a gas-fired water heater is about eight to ten years you are already on borrowed time.

If you have incomplete combustion a propane fired water heater can most certainly put out copious amounts of carbon monoxide, especially if the exhaust vent piping is compromised. This can also happen in a house of very tight construction that does not have additional air intakes for the water heater and furnace or sometimes by the use of exhaust fans in other parts of the house such as bathroom fans and kitchen range hoods.
Old 02-09-15, 02:01 PM
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Welcome to the forums.
Since the fire department did not get any readings, and since the CO detectors have been quiet since they were replaced, I think that you can rest easy as far as monoxide buildup.

Without hearing the sounds, it could be what is called water hammering - especially if it occurs when you turn off a faucet. No harm and there are ways to cure it although you may need a plumber depending on your skill level.

If the average age of a water heater is ten years, that simply means some died a very early death while others ran fine for 20+ years. Personally, mine is about 19 years old and the one I had before it went 26 years and was still fine when I sold that house.

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