Venting Gas and Oil into same flue
Hello All- I recently bought an older home and the natural gas hot water heater and the oil furnace are both vented into the same flue (actually it’s more like the gas is vented into the boilers flue and they share the same pipe for about a foot before they vent into the chimney). The oil guy who services the boiler recently told me that I should have them vented seperately and that it’s a dangerous condition. However, he said it in a very off-handed manner and really didn’t seem too concerned. Ordinarily I would just play it safe and have them vented seperately but due to the layout, it’s going to be a very difficult job (maybe that’s why the oil guy wasn’t pushing, he knows he’ll be the one stuck doing it!). The condtion appears to have been in place for at least he life of the hot water heater which is almost ten years old, but I don’t know if I’ve been lucky, or it’s not a big deal. As I’m sure my post makes obvious, I know nothing about this matter and any info anyone has would be greatly appreciated.Thanks,
Brian
Replies
If the water heater is that old, and running a separate flue is a big problem, how about replacing it with a direct vent water heater? (The kind with the PVC chimney)
"If your parents didn't have children, chances are you won't either."
Thanks for the imput boss, the only problem is money (or more specifically, lack of) I'd really like to avoid replacing the unit if I can. Unfortunately, if it really is a dangerous condition, I should just bit the bullet. In that case, you're probably right and replacement might be cheaper than rerouting the vent. Thanks again
I had the same setup in my last house. No one ever questioned
the safety of it and I can't imagine what he's concerned about.
Why don't you try contacting the manufacturers of the furnace and/or
water heater. You could also contact the local building inspector
and see if he has a problem with the situation.
I think your setup is not at all unusual, unless there's
more to the story than I know/understand.
That shouldn't be a problem. What can be a problem is venting a fuel fired appliance into the same chimney as a fireplace.
Had a gas fired WH retrofitted into my first house located in Nassau County, Long Island. Exhaust fed into the flue of the chimney just inches above the exhaust vent from the oil fired furnace. The plumbing inspector gave it a passing grade. And the plumber was no slouch either. Sort of a friend of the family to begin with, but he was a quality craftsman. So I don't think I got a bad installation.
Wouldn't worry about anything unless the draft in the chimney is weak (maybe too small) to begin with and expecting it to expel both exhausts, if thery were running at the same time, is too much. Then you might risk having exhaust fumes vented into living spaces.
A simple carbon monoxide monitor would warn you about that though.
A simple carbon monoxide monitor would warn you about that though.
Depends what you mean by "simple." Mean the $20 - if you're lucky it'll wake you up enough to call the hearse.
Get the $40 - $50 one with the digital readout: much more sensitive. If you're pregnant, have an infant or older person or chemically sensitive or immune system challanged or have heardt disease or are unusually nervous, get the $75 low level monitor at http://www.aeromedix.com
If your alarm goes off, call a good heating company - call the gas co or fire dept only as a last resort - they ofetnm don't know much about CO or CO testing.
(BTW, a CO alarm tripping can result from a smoldering fire, so if anyone you call tells you to open the windows, politely thank for for their stupid suggestion and try someone else. Amazingly, many fire dept give that advice!)
Thanks for the advice Bob. Those are all good points - I didn't realize there was that much variety in the devices. I have the standard $20 circular blob hanging on my basement ceiling courtesy of my local hardware store. Tomorrow, if I wake up, I'll go out to my local electrical supply house (??) and look for a better quality device.
John
FWIW, today I found a water heater that was producing well over 1,800 ppm in the flue gases (100 ppm is allowable max) and was spilling a fair amout from the combustion chamber (which had no flame guard and a home made cover snipped out of thin sheet metal which was caked with soot (a sure sign of CO production).
The owner told me his wife had been experiencing morning headaches so they had replaced the furnace with no effect, and that the $20 CO detector they had in the hall outside the bedrooms never made a peep!
<i>Everyone knows high levels of CO can kill, many don't know that regular exposure to lower levels can cause serious, long term health problems. <b> Just because you aren't dead doean't mean you don't have a CO problem!</b></i>