Advice on Carbon Monoxide and Solid Fuel Stoves

[HMS Cricket]

I have a query regarding a problem we appear to have with the solid fuel stove producing carbon monoxide. Several times over the past few months, our dectector has gone off. After the first time, as my boat was due its BSC anyway, I consulted a safety inspector. He passed the boat, but advised we didn't have sufficient ventilation. We have since added new vents, and cleaned and extended the chimney. From walking around the basin, I would say we now have more ventilation than most boats of comparible size. However, we still seem to have a problem. Last night, the detector went off again. We were cooking with LPG gas as well as having the fire going at the time, but the strange thing was, we had two of our big windows open. On one occasion, it even went off when we had the door open. It seems to me that if this isn't adequate ventilation, nothing is! It's not a very frequent problem; it doesn't happen every time we use the fire, but it is a bit of a concern, and to be honest, I'm running out of ideas as to what the problem is, and how to solve it.

 

I'm wondering if perhaps the design of my stove is just inherently unsafe. We have a boatman's stove on board, which can be dismantled for cleaning and fire building from the top. This means, unlike a lot of boat stoves, the top has gaps in it, and when the chimney isn't drawing properly for whatever reason, smoke sometimes blows out these gaps and back into the cabin. Most stoves, I've noticed, don't have any gaps in the top, so regardless of how its drawing, smoke and fumes still have nowhere to go but up the chimney, unlike ours, where it can flow back into the cabin. Could this be what's causing our problem, and if so, is a new stove the only solution? I'm not really an expert either on CO, or stove design, but this is all I can think of. It seems to me bizarre however, that we could have a CO build up with doors and windows wide open. My partner suspects the detector is extremely over-sensitive, but this isn't a risk I'm prepared to take. I only bought the boat in March, so this is our first winter with it.

 

I'd appreciate any advice or help you could give me. I can find a lot on the net about CO risks associated with LPG, but not much about solid fuel fires. I've also email the BSC organisation, asking their advice, but have yet to recieve a response. In the mean time, I'm relying on an electric heater.

[nbtafelberg]

You could have a dodgy carbon monoxide detector?

[HMS Cricket]

You could have a dodgy carbon monoxide detector?

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Yeah, that's what the other half thinks it is, but I don't really want to just assume that's the case, considering how dangerous it could be if it were a genuine problem.

[Trelawney]

Yeah, that's what the other half thinks it is, but I don't really want to just assume that's the case, considering how dangerous it could be if it were a genuine problem.

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Buy a second CO detector and see what happens when both detectors are running. It will tell you if one is over sensitive or if both keep going off then you know its the stove.

[stuart]

You have checked the battery as well?

[dor]

does you CO monitor have a digital readout or does it just go off? The former will give you an idea of what sort of level you are getting - some are oversensitive.

Aerosols can set them off, and at quite a distance, as butane & isopropyl butane are used now and the detectors can pick up on that.

If the door seals are ok on your stove then you should be OK, but check that the chimney is sealed ok - fire cement cracks too easily - use a black HT silicne sealant at the top of the stove.

Check the back of the stoves for cracks, squirrels etc can crack if they are used too enthusiastically with coal.

 

Better to have one too sensitive than one that doesn't go off at all! you can check that they are working by holding it over the exhaust.

 

I much prefer the one with a digital readout, which also stores max level.

[HMS Cricket]

You have checked the battery as well?

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The thing's only a few months old, so I shouldn't imagine that's the problem. It seems to be working normally; the green power light flashes once a minute when all's well - IRC from the manuel (which I've stupidly misplaced), it shines continuously green when the battery is low.

[HMS Cricket]

does you CO monitor have a digital readout or does it just go off? The former will give you an idea of what sort of level you are getting - some are oversensitive.

Aerosols can set them off, and at quite a distance, as butane & isopropyl butane are used now and the detectors can pick up on that.

If the door seals are ok on your stove then you should be OK, but check that the chimney is sealed ok - fire cement cracks too easily - use a black HT silicne sealant at the top of the stove.

Check the back of the stoves for cracks, squirrels etc can crack if they are used too enthusiastically with coal.

 

Better to have one too sensitive than one that doesn't go off at all! you can check that they are working by holding it over the exhaust.

 

I much prefer the one with a digital readout, which also stores max level.

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No, it just goes off; it's not a very hi-tech model. See, it's interesting what you say about cracks in the stove; as I said, the stove does have cracks in it, on the top, and around the base of the chimney, which are just part of the design of the stove (the top is made up of plates which are juts rested on, and lift off in order to build the fire. Obviously, these aren't sealed as they have to come off). This is where smoke leaks out into the cabin space from when the chimney's not drawing properly because of weather conditions or whatever. By adjusting the ventilation flaps, you can stop it from visibly smoking - but of course, CO is invisible, and I can't help suspecting it's just leaking right out the stove through these cracks.

 

Might invest in a model with a read-out as back up. See, I'd be tempted to just buy a new stove and have done with it, but we're shortly selling the boat to get a bigger one (with room enough for two ), and stoves are pretty expensive. None the less, as you can appreciate, I don't want to sell anyone a boat that's potentially lethal!

[John Orentas]

I would be inclined to double check it against another unit. It may well also be critical as to the location were it is mounted.

 

I know it is not the same thing but I have never been able to get a smoke alarm to act sensibly, no matter were I put it, it insists on letting me know that I am cooking breakfast.

 

In my experience all stoves 'blow back occasionally', A few leaks shouldn't matter as they should suck rather than blow. I assume you have a double skinned chimney. I have recently made a 'swinging' top for mine, works a treat.

 

John Squeers

[timboharticus]

"swinging top chimney" ???

 

Is this like a wind generator with a pivot and fin?

[Richard Bustens]

Hi i have a sawdust burning stove in my workshop and if that is not set right it soon lets you know , with a allmighty bang.

It seems to work on the fact that the chimney is hot and the heat pulls the cold air into the fire box, when i first light it it smokes like mad but when going for a bit there is no smoke at all.

But it is a dam sight safer than the old salamanders we usto use 30 years ago.

Edited November 29, 2004 by Richard Bustens

[John Orentas]

Something like that Tim. I am now working on one that fits on my head, keeps the rain out of your face, forgot to put a window in it though I keep bumping into things.

 

John Squeers

[dor]

I am sure I said this recently elsewhere, but if your stove can leak smoke, it can leak CO. A stove should not leak into the cabin; not when you light it, not when it is ticking over, not when it is flat out. That is the point of a stove. You light it and shut the door, air draws in at the bottom and goes up the chimney. I find it remarkable that a stove can be sold with designed-in leaks between panels.

CO is an insidious cumulative poison, don't take risks.

 

But do check your monitor, and don't bother with a cheap one, get a decent one that is reliable.

[Paul Evans]

I agree with Dor (that's the second time tonight). Replace the stove with one that is not designed to leak very dangerous gases into the boat and get a decent CO monitor/alarm. What price do you place on life?

[Tommo]

I had a problem a few months ago, when in the middle of the night the CO detector, which is on a shelf in the bedroom detector went off. B***** hell I thought and jumped out of bed to investigate, we had no fire going and could not find the reason it went off, after letting some fresh air in I reset the alarm and went back to sleep only for the same thing to happen again about an hour later.

Thinking the unit must have developed a fault I moved it into the galley until the next morning. When we left the boat after the weekend I put the unit back in its usual place on the shelf in the bedroom, when I called in during the week I found that it had triggered again, with nobody on board. This made me search out the instructions for the unit and it said that some air fresheners could set it off. Wife had stood a smelly air freshener thingy right next to the alarm unit..moved it away and problem solved.

 

Tommo

[Martin]

We have a leaky stove too - it was built in 1901 though, so I forgive it the odd leak as it looks good and we use it for cooking on.

Don't misunderstand me though - we are careful, know its habits and have a CO detector.

Ours also has the removable plates on the top for cleaning - it is impossible to get the soot from around the oven without.

I have tried cementing fire rope around all the plate edges - which works for a while but the rope comes loose after a while.

I have tried HT silicon - recommended by Lime Kiln Chandlers (the red stuff) and this was good for a while but then too succumbed to the heat.

Part of the problem with the silicon is that you don't actually want to glue the plates together so I coated one surface with vaseline so that the silicon moulded to the right shape but didn't stick.

(Part of the silicon's failure might have been due to the vaseline attacking it of course!).

 

One thing that does work with ours is the flap that we had made which covers the front of the firebox itself which is designed to be open.

The idea behind this was to close the fire down at night and keep it smouldering lightly.

In effect it makes it draw far better from below and has the opposite effect to that which it was designed for.

It DOES stop the smoking though.

 

Finally, where is your CO detector physically located?

The instructions with mine warns against placing it near the CO producing appliance.

Doing this is like sticking your smoke detector right above the toaster!

It recommends putting it in the area in which you live.

Thus we have ours in our hallway which is between the galley and the bathroom with the bedroom beyond.

Here it still gives peace of mind while in bed but is far enough from the stove that it isn't set off by the smoke that leaks out when it is warming up.

[HMS Cricket]

Thank you all for your help and responses. The more I think about it, the more I'm inclined just to buy a new stove for peace of mind; in fact, even more so if I'm going to sell the boat, as I'm unlikely to be able to sell it if I explain the CO problem to potential buyers, and of course I'm not going to sell it without warning knowing there's a problem...

 

The detector is located on the other end of the boat from the stove and cooking appliances, although that's only about fifteen feet away (the boat's not very big). The only reason I suspect the detector itself may be faulty is the fact it goes off even with doors and windows open. You'd think, even if we did have a CO problem, the fresh air coming through would prevent it building up until such time as we close the windows. We don't have any air fresheners on board, and I've never noticed activation of the alarm coincide with us using deodrants! I do have those colour-changing pad detectors as well, and they never seem to change colour, but I know certain factors such as heat and humidity can make them unreliable. Anyway, I just got a response to my email to the BSC, advising me to get the stove looked at by a professional before using it again (I haven't been using it since the last scare). Considering the potential call-out fee, again, I might just invest in a new one. I'm sure the old one would make a very fetching flower pot!

[HMS Cricket]

I would be inclined to double check it against another unit.  It may well also be critical as to the location were it is mounted.

 

I know it is not the same thing but I have never been able to get a smoke alarm to act sensibly, no matter were I put it, it insists on letting me know that I am cooking breakfast.

 

In my experience all stoves 'blow back occasionally',  A few leaks shouldn't matter as they should suck rather than blow.  I assume you have a double skinned chimney.  I have recently made a 'swinging' top for mine, works a treat. 

 

John Squeers

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Yeah, I do take your point; when I discussed this problem with my mother, she pointed out their smoke alarm goes off whenever they cook pork chops! None the less, at least when a smoke alarm goes off, you can easily locate the problem and judge for yourself how trivial (or not) it is, but CO being invisible and odourless, it's a bit risky to make a judgment call when you don't really know.

[John Orentas]

Or keep it going and buy a canary.

 

John Squeers

[Paul Evans]

Now John, you're not going to suggest spit-roasted canary, canary beak soup or other culinary delights, are you? Oh, you are!

[Bones]

is there anything you can put into a stove to check for leaks... like a red smoke dye thing?

[magnetman]

is there anything you can put into a stove to check for leaks... like a red smoke dye thing?

 

Perhaps lots of paper in the stove, baffle closed and air vent closed, smouldering it should produce masses of smoke and seep out of any cracks.

 

I got a digital readout CO monitor from B&Q for £35 and I can get a reading onto it if I stoke up the stove really well and shut the chimney baffle too far. It also rises and sometimes sets the alarm when I run a petrol generator on the back deck cos the fumes blow in through the doors.

I am very sensitive to CO getting bad headaches so a detector is important.

[Bones]

Perhaps lots of paper in the stove, baffle closed and air vent closed, smouldering it should produce masses of smoke and seep out of any cracks.

 

I got a digital readout CO monitor from B&Q for £35 and I can get a reading onto it if I stoke up the stove really well and shut the chimney baffle too far. It also rises and sometimes sets the alarm when I run a petrol generator on the back deck cos the fumes blow in through the doors.

I am very sensitive to CO getting bad headaches so a detector is important.

 

 

We probably have the same detector! I have one but can't work out where the leaks are! I will have a go at smoking paper thing. Thanks.

[magnetman]

We probably have the same detector! I have one but can't work out where the leaks are! I will have a go at smoking paper thing. Thanks.

 

GOod plan.

[WJM]

Where should a CO detector be located - high or low?

 

Boats and CO are a dangerous mix - I always have two different detectors on board to cover for failure or quirks of one particular design - this seems a bit obvious to me given their cost relative to a life. (same strategy with smoke alrms too)