Just had a CO call

Steve Ebels_3

Scenario was as follows. It was 9:45PM and still in the mid 80's when I got a call from these folks that their CO alarm was going off. When I got there it was apparent almost instantly what was going on. They have a whole house fan and the matron of the house was doing laundry. Add those two together for just a second and tell me what was happening to the flue gas from the water heater.

Can we all say SPILL!

The flame on the water heater was a brilliant yellow with nice smokey colored tips and all the flue gas was being vented into the house. This of course was due to the fact the the whole house fan turned the chimney into just one more avenue of incoming air.

When I showed them what was happening they could understand that they had to open ALL the windows in the house in order for the chimney to stay in an updraft mode. They also decided that they would run the fan only when they were not using hot water.

What else could I advise them to do? I'm not 100% comfortable with this.

Mark Hunt_2

I hate those damn things!

"Whole House Fan"?????? Not a very big "fan" of the people in the house though are they?? But they are just stupid pieces of mechanical equipment doing EXACTLY what they were designed to do. Maybe if you taped arrows in the chimney pointing "UP" the problem would go away?? Just kidding. (You know that anyway)

Chimney's are usually the biggest hole in a home and they are bi-directional. It's all physics as you know Steve. High pressure goes to low pressure ALWAYS. I'd get rid of the WHF OR make a BIGGER opening in the house to equalize pressure when the fan is running OR 86 the atmospheric appliances and power vent all of them.

The water heater will fire even when they have not used hot water and they will not even know it is happening. I'd opt for choice #3 AFTER I prove that the inducer motor will overcome the depressurization, in the mean time I would disable the WHF. Major source of depressurization. Rather have them sweaty, stinky and breathin', than clean and "room temperature".

Wanna' hear the scary part??? It happens in every home that has a WHF!!!. These folks happened to have a CO alarm that was working to some extent. Most do not.

Let me know how you make out. You know where to find me.

Mark H

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

joel_19

Hey!

funny you should bring this up . I've got a house where they now have a problem with flue gas backing out the boiler draft hood and it never used to happen . It's a very clean running euro boiler and the highest recording of CO in the basement has been 79PPM . Low but it's there and it does fog up the cellar window on occasion. Doesn't happen all the time just occasionally. They installed an attic vent fan (not whole house). I've got a theory that when it runs it pulls the basement negative through some internal chases/wall cavities. Trying to get a blower door test now so i can be proven wrong or right!

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Constantin

Well, there is a simple solution...

.... move the appliances out of the house or replace them w/sealed combustion models. That was one of the premises of the outdoor gas water heater I helped develop (besides being less expensive to install outdoors than indoors). DV-based boilers do the same thing.

... scenarios like this are precisely why I have a damper that opens a 9" intake from the exterior into the AC return whenever the kitchen hood is fired off. While the 900CFM-rated hood will likely overpower even a 9" intake, it's better than nothing.

Rich P_3

Gas boiler

Its to bad they don't realize you may have saved
the lives of them or their Grandchildren??
Last year (October?) I replaced a old gas boiler and installed a shiny new Crown boiler. The customer called a day and a half later and the heat was off.
Flue gas spill switch had tripped. I thought this was unusual, large open basement, old windows and the like.
It turns out during the previous summer the roof was replaced and the attic ventilator fan was stuck on(bad thermostat) This was the culprit. Its so hard to believe this could cause such a scenario, but it did.
Thanks keep up this interesting stuff.
Remember your doing the right thing!
Rich P.

Steve Ebels_3

IMHO

To make a WHF foolproof you would have to have an electrically interlocked inlet shutter (of adequate size) that opened whenever the fan was turned on. Most people however, don't want a 9 square ft shutter in the side of their house for some odd reason.

Direct vent, sealed combustion, and I mean truly sealed, appliances are definitely the answer.

Mark Hunt_2

You don't need a blower door test Joel


Simple as testing draft when exhaust fans are running. ANY fluctuation is cause for concern. If there is an air handling piece of equipment in the home, turn it on as well. You'd be amazed at what happens with an improperly balanced or leaky duct system.

Any air that leaves a structure MUST be replaced. A chimney is bi-directional. Why do you think "draft diverters" were invented in the first place?!?!? So that in the event of a "down-draft" or "blockage" of the chimney, the appliance would continue to operate!!!! It's in the book!

Joel, if you need further assistance, e-mail me for my personal contact info.

Mark H



To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Mark Hunt_2

You are 100% correct


What was the chimney designed to do? I mean originally? Was it designed to cause draft? In a Teepee? The teepee WAS the chimney. Hole at the top, "make-up" air at the bottom. The chimney was originally designed to give the smoke a way out. That's all. A smoke escape. Draft had nothing to do with it. You think Sitting Bull worried about CO poisoning?

Well now we have "smokeless" fuels. So what is the chimney for other than acting as an exhaust and intake simultaneously???

Time to move on. Good-bye chimney, hello sealed combustion.

Shut the WHF off Steve. If these folks ever sell the house, I promise the next folks will NOT know about that "little" back-draft problem.

Mark H

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Dave Yates (PAH)

Been there too!

Gray hairs to prove it(G).

http://www.contractormag.com/articles/column.cfm?columnid=37

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Steamhead

Shows what oversizing will do

Dave, great story. The fan Steve was talking about was probably oversized too. Do any of you remember the proper methods for sizing whole-house fans in the old days? I know there was something but can't remember what it was.

BTW, the old days are still alive and well here. With big trees, a gravity-vented attic, an oscillator in every room (mostly 16-inch) and one of these old Sears beauties to draw the heat out at night, who needs A/C? It's only 20-inch and blows thru a standard window screen so it doesn't cause backdrafts. Of course, we open the windows before turning it on.....

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Dale

Attic fan

We have had this happen. Attic fan and the end louvers are blocked or the proper vents blocked or not enough free area and the space around the stack vent, chimney ect not sealed. Worse one for us was a attic fan that started on moisture sense and had no switch, cold damp weather and CO after a long night.

Mark Hunt_2

Ever consider one of these?


Mr.Slim

Quiet!!

Mark H

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Mad Dog_2

Joel! 79 ppm is NOT a low number

I consider anything 5 ppm or lower perhaps incidental, but form what source. We have a zero-tolerance policy on co in a living space. That house needs a good going over. Mad Dog

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Mark Hunt_2

ZOINKS!!!!!!


I have to wonder how many systems are out there where this is happening to some degree.

I guarantee that if that house had burned completely, the blame would have been placed on the "faulty water heater".

Good thing you knew enough to look around and get nosey.

I'm going to keep that story for future use.

Thanks Dave!

Mark H

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Mad Dog_2

Thank God newer boilers have spill switches

I worked on a new Burmham last week though the some moron have jumped out!!!!!Mad Dog

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

John R. Hall

Ebels is pulling your legs

Never gets above 60 degrees in Falmouth. :-)

Dave Yates (PAH)

more common than we ever thought possible

We've run into this on odd occasions when the fault was laid to rest elsewhere by the building owners.

Factory: Boiler in a mechanical room would go into a no-heat condition. We'd respond only to find nothing wrong. On my third trip, I was just about at my wit's end (might have actually lost them long before that!) & wondering what in the world was happening to cause the nuisance trip outs. Outside of the mechanical room, there were two new CNC machines. Each one had a roof-mounted exhauster to strip away waste heat & you guessed it - whenever the exhausters ran, the chinmney reverse-drafted, which pulled the pilot off of the thermocouple. I was observing the flame when it happened & the door to the factory from the mech room was closed. Had I known then what I know now about CO, I'd have moved my car-cass out of that rather confined space & aired it out. Resolution? Disable the rooftop exhausters and install sidewall fans to move air into adjacent factory areas that wanted to be heated anyway. Fans in roof go back into operation in summer only.

Machine shop: Modine heaters back-drafting, which toasted the controls! Newly installed roof-mounted exhaust fans were the culprit. Resolution - new modines with powered exhausters built in to establish anmd maintain positive draft.

Commercial restaurant: Burkay 1-million Btu gas-fired water heater whose coil froze and split. Kitchen hood went unbalanced because the cooks complained about frozen tootsies. They'd disabled the make-up air, which then set up one heack of a downdraft in the adjoining mechanical room. Fresh air was drawn in via the water heater's exhaust. Resolution: Restore make-up air and install motorized damper on water heater's flue.

Residential: Darn near every residential whole-house-fan installation causes back-drafting in standard masonry chimneys. Just ran into one today after our burglar alarm had an overnight malfunction. The alarm company owner, in casual conversation, asked why he was having problems with his water heater pilot going out whenever he ran his WHF. Resolution: cut wires to WHF!

Once you know it's out there happening with great frequency, it's easy to become more aware and find examples.

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Steamhead

Yes I've seen those

But the house generally stays cool enough without them.

There was a thread some time ago on indoor air quality, and how many times outdoor air was actually healthier than indoor air. No-cost solution? Open the windows, especially during warm weather. Yet many windows are never opened no matter what time of year it is.

And think about this: many homes and businesses are always kept somewhere between 68 and 78 degrees all year. Most vehicles are too. Will we eventually lose our ability to survive anything else?

The fan is going as I write this. I'm sitting in a cool stream of fresh air coming in the window. The house temp will be in the low 70s tomorrow morning, and might reach 80 by sundown tomorrow. So we don't need to pump Freon, and this keeps us from becoming a "preferred" BG&E customer.

Besides, The Lovely Naoko hates A/C.

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Dave Yates (PAH)

Hey!

Keep that to yourselves, I'm a Mitsubishi Diamond Dealer & need the business(G).

Inverter Technology - you'd love it - works just like the Munchkin with true variable speed for the refrigerant flow and all motors within the system. Multiple indoor units off of one single outdoor unit and all communicate with the system for outdoor/indoor reset. Tis the future of A/C & heat pumps IMHO. Seers vary too & range into the upper 20's dependent upon load conditions.

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Steve Ebels_3

We get

12 days every summer that hit 90*. We've already had 4 and have all of June, July and August to go. I'm planning on a frost around the end of June or first of July. August will be decent and winter will set in during September. That gives the black flies and mosquitoes about 3 weeks yet and they'll be froze out.

Doesn't really matter what the weather guys say. It'll happen how it happens.

A person hardly has time to get the boat out and you have to start thinking about waxing up the CC skies.

You're funny John.

Steve Ebels_3

Solution to this one...........

Called the guy back today and explained in detail what is going on. We're installing central A/C Friday.

Mark Hunt

Mitsubishi


I just attended the service training in Atlanta to complete my Diamond Dealer requirements.

The Inverter series is amazing.

Wall hung boilers with wall hung A/C.........it doesn't get any better!

Mark H

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Glenn Harrison_2

Watch out for attic ventilators too

I have had numerous situations where power attic ventilators have caused a negative in the house and the water heater spills all summer long till caught. theres never enough soffit vents for these things.

Was doing an A/C tune-up a few weeks ago and noticed when I changed the furnace filter I could hear a fan running in the furnace room. Turned out the combustion air intake going to the attic had about a very high air flow OUT of the furnace room and into the attic. Attic fan was running and the 30 year old attic wasn't even close to being vented properly. Solution, add sidewall combustion air, cap off attic intake, and add lots of soffit vents. Attic ventialtor diasabled until repaired.

Steamhead

With enough soffit and gable or ridge vents

you don't need a power attic vent. That was one of the first things I added to my house- they complemented the existing gable vents. Without them, my attic would exceed 145 degrees! Think about it- that's a 65-degree delta-T if you keep the A/C at 80. For comparison, in the winter that would be 65 inside and 0 outside. Insulation slows this down but doesn't stop it, since everything up there gets heat-soaked. You really notice this when the heat is still shining down from the ceiling at 3 AM. I don't know how my grandmother put up with it.

With proper vents, the attic never gets more than 10 degrees above the outside temperature. And that's just on gravity circulation- if the wind is blowing the delta-T is smaller. If we ever do put A/C in here (over T.L.N.'s dead body), this will allow us to use a much smaller system.

The technique worked so well that I did the same thing at my parents' and sister's houses. The former, a 1-1/2-story Cape Cod, has no attic- just the space between the ceiling and the roof deck, part of which is taken up by insulation. The second floor (which is where my room was) would flash hot as soon as the sun hit the roof- and window-shakers didn't help. Now it's habitable, even with the present A/C off. And the paint no longer peels off the soffits and trim.

Installing the vents at my parents' house turned out to be a demonstration of the power of gravity circulation. For these, I used 4-inch round grilles and cut the holes with a hole-saw. As I finished cutting the first one, I started to move out of the way of what I thought would be a lot of debris falling out of the hole. But the upward air current was so strong that it pulled everything into the hole! That's the power of Mother Nature, and it doesn't add to the electric bill or depressurize the house.

So why aren't most attics properly vented? Vents cost money, and we all know how builders strive to shave every penny from the cost of building a house, no matter how bad the effect on the buyer will be. And of course, utilities don't encourage this type of venting since it would mean they won't be able to sell the owner as much electricity in the summer.......

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Dave Yates (PAH)

great course

And a fun test lab setting too. The City-Multi is a wonderful multi-tasking beast!

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

BillW@honeywell

Good point, Steamhead.

I can totally agree with you. Had a new roof done about 3 years ago,with ridge vent and added more soffit vents. It DOES make a big difference, even in the unconditioned garage. If you're planning a new roof, take this added step, and you will be glad you did!

Steamhead

And I'll bet

it didn't add that much to the job cost, eh?

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

dean_10

vents

Again steamhead is right. I added gable and roof vents to both of my attic spaces. The result was exactly as he said.

dean_10

CO

From personal experience. Several years ago when the original 70+ year old boiler was still in operation in our home we had a minor sewage backup into the basement due to a root clog. While cleaning this up I opened one of the basement windows and placed a small box fan in it to help ventilate the basement. This was late fall and the boiler was running. About ten minutes later I noticed I had a headache and the nail beds of my fingernails were cherry red. These are both symptoms of exposure to HIGH levels of CO. I shut the boiler off, opened all the windows, and got medical attention immediately (which is what anyone exposed to CO should do). Later I recreated the situation with the boiler off you could feel the air spilling from the boiler draft hood after the heating people came and checked the gas conversion unit on the boiler. They also told me what was happening. The point is it obviously doesn't take much to create these dangerous situations and most people don't know it. I didn't at the time. And the end result is exposure to CO.

jerry scharf_3

What are the specs on the city-multi

Dave,

I grovelled the web site and couldn't find the full power SEER rating (or comparable) anywhere. I know the deal with running at reduced speeds, and curves representing that would also be nice. Can you either post the info or a link to the detailed specs.

thanks,
jerry

joel_19

update

The 79 PPM recorded the owner admited was from car exhaust from the drive under garrage. We did the blower test . Yes I know we could just test for draft but I wanted to see more. turns out that any combination of two bath fans or the range hood pulled it negative . It was nice to visulize this to the home owner with the testing we did. esp when even with blower door set low we could show them the same thing happening with the fire place upstairs.


To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"