Need Advice for CO Detectors Going Off.

Hi everyone. I'm new to the boards and feel like I am still a rookie with me Harman SF250. I have had the stove for 4 years now and I have had to call the fire company 3 of those years for CO detectors going off. My problems always seem to happen in the Fall when the temperature gets around 60. The latest incident was Monday when here in PA the temperature reached 65. The stove is in my basement with an insulated concrete block chimney that extends beyond the highest point of my roof. I have a Field controls barometric damper on the stove too. Monday,I was running the stove with the ash door knob opened 1/2 turn and the load door knobs open 1/4 turn each.

What am I doing wrong? Is it too early to have the stove running with the warm weather this fall? Do I need to have the stove running hotter ( my flue pipe was between 90-100 degrees where it entered the thimble)? I do not have a manometer (never heard of it until I started reading these forums. I thoroughly cleaned the stove, swept the chimney, and brushed out all the stove pipe too. I don't see and outside rust or weak spots on the flue pipe. I'm a little scared of the stove (and the CO) because I am obviously doing something wrong. I would really appreciate any advice.

Thank you in advance.

Crack a window open in the basement. Sounds like you have low pressure there. Also open your secondary air more. This will provide more heated air to go up the chimney and should help the chimney pull. Do you have a manometer installed? I highly advise you get one. They are inexpensive and a great resource to monitor chimney draft.

Mine would go off once and only once and then I would make significant changes to ensure that, I understand all set ups are different but your situation is 3 yrs. running, don't want you sleeping through the next alarm and a manometer would be on the short list! Me and my family is worth every single dime...priceless

IH Cub wrote: Monday,I was running the stove with the ash door knob opened 1/2 turn and the load door knobs open 1/4 turn each.

You need to improve the draft for your chimney. Before we can advise we need some more information

Where are you located? A forum member might be close by and willing to stop by and look at your setup for you.
How old is your house? New houses are built tight, sometimes too tight and you don't get enough air exchange much less air for combustion.
Why did you have the ash knob open and the load door know open at the same time? Usually one or the other depending on what your burning
You said your stove is in a basement. Would you consider your house pretty tight? It may be too tight and starving for air causing a reverse draft.

this should be enough information to get things going.

Rev. Larry

During the bridge weather i.e. spring and fall, your chimney is losing effectiveness due to too small of a temperature difference between the top and bottom of the chimney.
Among the solutions are: 1) Increase the height of your chimney, 2) Increase the size of the fire in your appliance, or 3) Add a draft inducer to the chimney. For example: http://fieldcontrols.com/draftinducers.php
A draft inducer with speed control may be used until the outside temps are cold enough and then shut off for the Winter.

Thanks for the replies. To answer some of your questions:

1. My house is located outside of Scranton, PA
2. My house was build in 1998. I finished the basement over the summer and tightened everything up with foam insulation (in hindsight, not the best move for a coal stove).
3. I did not have any windows open in the house (from reading posts, I am understanding the importance of not having negative pressure in the house).
4. I burn chestnut coal and always have the stove loaded up to the firebricks.
5. I was under the impression that the ash pan door knob regulated the burn of the fire by letting air pass through the fire from underneath and the load door knobs only served to let in extra air to burn off residual gasses. Is this right?
5. I do not have a manometer. Would anyone have advice on how to install one? Do I have to drill a hole in my stove pipe? What do I insert into the stove pipe that will not melt?

It seems like maybe I need to run the stove harder (ash pan door control 1 full turn open is the minimum) and use the windows in my house to regulate house temperature?

Wouldn't opening the load door knobs let less air pass through the fire from underneath and cause the fire to smolder?

One potential solution would be to bring in outside air to near your soild fuel appliance. I recently calculated that for 100% efficient combustion of the carbon (C) component in anthracite into pure CO2 it takes fully 922 gallons of air per pound of coal burned. Therefore lots of air is required.

Others will know the requirements better than I do, but I recall needing at least 1 square inch of outside air duct delivered supply for every 1,000 BTU's that your solid fuel appliance is rated for. A 100,000 BTU rated stove (boiler, furnace) would require an outside air duct with a cross sectional area of 100 square inches. There are rules as to how to do this also. Something about air must be supplied near the celiing and also near the floor, and these supplies need to be via separate ducts. Someone with access to codes will need to assist and clarify this for me (us).

Manometer is a Necessity. Obviously you didn't have or lost proper draft. Setting controls on the stove can only be done with a manometer in conjunction with a barometric damper. Sounds like your chimney is up to snuff, however losing draft in warmer weather is not unheard of. Crack a window near the stove and burn a hotter fire than you would normally like during warmer weather to establish better draft. That's what windowstats (open windows around the house) are for! Lol!

I used to have the same problem in warm weather burns. Cracking a window in the basement and opening up the secondary air more has never failed me.

It makes sense that more secondary air will rob air from the primary but it will not. You would need to exceed the volume that the chimney can take for that to happen, by for example, opening the load door.

We all agree a manometer is needed. Most of us use the Dwyer Mark II model 25. Don't get the model 27. It's simple to install with a 12 inch section of brake line into the pipe.

Get a CO2 detector with the PPM display so you can see what it's at.

They have thresholds for X amount of time. If it reaches and stays at X PPM for X days it will go off, if it reaches and stays at X PPM for X hours it will go off, if reaches X PPM where it's lethal it will just go off.

It's important to understand the risks of why it's going off and keep in mind at high enough levels you're just going to fall over and die so that leaves you in bind doesn't it? . I understand they want to keep them simple so people are as safe as possible but if they are going off a lot at non lethal levels the "crying wolf" issue creeps in. I don't know if they make them but what they really need is 2 different beeps, one to let you know there is a problem and another for Run!

You are not alone in the low draft season temp swing issue. I personally like the draft inducers, and variable speed is desirable. No more issue, because CO2 does not give second chances.
Family, pets and friends...not necessarily in that order, depending upon how each group scores with you, but that is a different story............

Most of the more expensive detectors have a alarm memory with the levels recorded. Very helpful is assessing the cause and duration. The ones we use say DANGER, CO2 presence, EVACUATE IMMEDIATELY. It is VERY loud and gets your attention....everyone's attention.

I use the Night Hawk model by Kiddie. It has the digital display. Before I learned the trick with extrar secondary air bye cracking a window, it would show me low level counts whenever I smelled coal exhaust. It shows readings over 30 ppm but doesn't alarm till the level gets higher or the level endures a specific period of time.

They are available at HomeDepot around $40.

I too have the Kiddie brand with the digital display and I thought they were faulty, never ever had a reading. Then my wife decided to almost set the kitchen a fire with some bacon and the hallway monitor picked up a 5 ppm reading, sucked we ruined some bacon but good feelin knowin the monitors work.

Welcome to the forum!!

I would leave the secondary air where it is and open up the ash door knob a little to encourage the coal to burn a little hotter. I understand what Lightning is saying, but in this case I think it is better to get more air through the coal bed so the stove temp is a little higher. I would also put foil over the barometric damper until colder weather is more consistent. The minimal extra coal burned keeping the stove a little hotter is not worth worrying about over the CO issues.

Another vote for the Kidde digital CO monitor...in fact get two! One by the stove and one in a hall outlet outside the bedrooms. Plan on getting a third in about two years and then rotate them out of service about every 5 years. Use a sharpie and write the date on them so you know when you bought them, time flies by and before you realize it those things are 10 years old and not reading correctly!

Also another vote for the manometer. It is very useful when setting the weight on the baro, I hate trying to read those little scratched scales on the baro. also if you leave the manometer connected you will get used to the "proper" reading for normal burning and will probably be able to tell by seeing a lower reading if you are getting fly ash built up in the pipe or stove.

I don't know the interior of the SF250, but does it have a baffle plate at the top of the firebox? Other Harman models have this and the fly ash will lay on that plate and impede the exhaust. If there, it needs to be vac'ed off at least as often as the horizontal flue pipe sections need to be cleaned.

First of all, thAnk you for all the wisdom about burning coal. I have a monoxide detector on every floor of our house (3). I just bought a kiddie with a digital readout to put in the basement too (I already have one next to the stove, but it doesn't display CO levels.).

My basement is about 1000 sq ft and the stove is at the "buried" end of the basement. My 2 windows are on the other side of the basement (about 20 feet away). Would opening one of these an inch or so help with negative pressure or does the outside air need to come in closer to the stove?

I understand everyone says a manometer will take the guesswork out of the chimney draft, I'm just not confident about drilling a small hole in my flue pipe (I probably need to get over this).

I really appreciate the advice.