NOW THAT SUMMER is over and a slight chill is in the air, estimates for new heating systems are once again on the front burner. During the course of each visit, I now find myself striving to educate homeowners on carbon monoxide detectors and why every home should have them for occupant safety. For information regarding CO's properties and why it's so deadly, see my previous column. ( August 2002, pg. 26, or www.contractormag.com/articles/ column.cfm?columnid=137).
Case in point: I'm the last bidder in on a two-zone boiler. It's an oil-fired unit and when it was last cleaned, the inexperienced lad doing the work destroyed the firebox liner by sucking most of it into his vacuum cleaner. Upon refiring the unit, the heat transferred through the jacket while he was going over the work with the owner
and scorched three sides of the boiler! An acrid smell filled the room as the paint was blackened. The owner asked him if that's how it's supposed to work. Then, while they're standing there staring at the ever-spreading scorch line, it
cracked due to thermal stress (this was a hot water, not a steam, system).
So while I'm explaining why I want to repipe his boiler with an air eliminator, new bladder-style tank and relocating the pumps to eliminate the nagging air problems — I notice the gas-fired water heater looks dirty around its draft diverter and that its
thermal expansion tank is undersized. I gave a quick glance at the burner access door to check for signs of scorching — none there.
New questions! When was the boiler cleaned?
A month ago. Was the chimney checked? He said he cleaned it.
I'd turned up the Unitrol aquastat on the water heater as I was asking these questions.
It's an old row house with a threestory, brick-lined chimney. You know the type. No liner, but it's also in the center of the building and not exposed, meaning one could reasonably expect to install a new standard efficiency boiler without needing a chimney liner, although we always recommend one anyway to CYA (cover your assets).
Flue gases immediately spilled out at the diverter, which is not atypical for a cold brick chimney on a dreary day when outdoor air is effectively stopping any natural draft. But this was not a dreary outdoor day and the sun was shining bright, a beautiful fall day. If cold chimney draft was the issue, the input from the water heater would have overcome that problem by now and I told him I thought the chimney was clogged.
Can't be, he said, it was just cleaned. Here, put your hand close to the diverter, I said. Be careful, the flue gasses are very hot.
Turning off the water heater's burner, I touched the flue piping immediately beyond the 90-degree ell perched atop the draft diverter. It was stone cold, another indication of no draft and a blocked chimney.
So his wife asks: "Is this why our CO detector went off? He took it down and removed the battery thinking it was defective. We didn't feel sick, so we were planning to replace it."
Good grief! When a CO detector goes off, you need to find the source of the problem, not disable the detector. Next time, call us. We have sophisticated CO detection equipment and can locate the source, and your local fire and emergency service personnel can respond too. Don't ever ignore such a warning again.
With the ell and diverter removed, we used a flashlight to look into the 3-in. flue piping. Solid dirt/soot/mortar was plainly visible. Before proceeding, I had them take my flashlight to see this for themselves. As I removed the boiler's 6-in. flue connection for accessing the chimney base, they both were discussing their disgust for the company that had "cleaned" the boiler.
I removed several boxes of debris from the chimney, enough to clear the water heater's flue, but not all that would be necessary to complete the job. I explained that if we performed the boiler work, that the chimney would be cleaned down to the base where an old cleanout door had been cemented shut — another 3 ft. lower!
I left that day knowing I'd done the right thing by finding the blocked chimney and taking the time to clean it to a point where safety was restored.
Take a few minutes to discuss CO issues with all your mechanics as we enter into this year's heating season. Encourage them to look beyond the scope of the day's work to help seek out problems with blocked chimneys. Ask the owners questions and if you don't already own CO detection equipment or combustion analyzers that measure CO, buy one today.
Dave Yates owns F.W. Behler, a contracting company in York, Pa. He can be reached by phone at 717/843-4920 or by e-mail at [email protected].
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