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A carbon monoxide question.


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In Wickes recently,saw that they had on offer a smoke alarm and a carbon monoxide detector,both decent makes (Fireangel and Honeywell)

Decided to treat the boat to them as the ones fitted have been on for several years,and as there is a diesel heater fitted,I thought it a good idea.Testing the carbon monoxide detector by the test button and also holding it to the car exhaust (petrol) it sounded off.

However holding it to a diesel exhaust,not a peep.

There appears to be not enough carbon monoxide in diesel exhausts to set the alarm off.

In the event of my diesel heater exhaust leaking,apart from the smell (if I am awake) what other warning is available?

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1 minute ago, Mad Harold said:

In Wickes recently,saw that they had on offer a smoke alarm and a carbon monoxide detector,both decent makes (Fireangel and Honeywell)

Decided to treat the boat to them as the ones fitted have been on for several years,and as there is a diesel heater fitted,I thought it a good idea.Testing the carbon monoxide detector by the test button and also holding it to the car exhaust (petrol) it sounded off.

However holding it to a diesel exhaust,not a peep.

There appears to be not enough carbon monoxide in diesel exhausts to set the alarm off.

In the event of my diesel heater exhaust leaking,apart from the smell (if I am awake) what other warning is available?

 

There is much less CO produced by an efficient running Diesel than there is by a Petrol engine.

 

However, if your diesel heater is not burning correctly, that is another matter entirely and a diesel can emit large quantities of CO.

 

It is similar to the flames an LPG hob produces (and why the BSS exaaminer has to check the flame colours as part of the BSS - allegedly !!)

 

 

Extract from the BSS for 'private' boats :

Screenshot (307).png

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9 minutes ago, Mad Harold said:

In Wickes recently,saw that they had on offer a smoke alarm and a carbon monoxide detector,both decent makes (Fireangel and Honeywell)

Decided to treat the boat to them as the ones fitted have been on for several years,and as there is a diesel heater fitted,I thought it a good idea.Testing the carbon monoxide detector by the test button and also holding it to the car exhaust (petrol) it sounded off.

However holding it to a diesel exhaust,not a peep.

There appears to be not enough carbon monoxide in diesel exhausts to set the alarm off.

In the event of my diesel heater exhaust leaking,apart from the smell (if I am awake) what other warning is available?

 

Almost all diesels take a full cylinder of air for each cycle so there is always more oxygen in the cylinder than is needed to burn the fuel completely.  Any incomplete combustion  will be a result of faulty injectors producing streams or great blobs of fuel that don't have time to fully combust before the exhaust valve opens. Its incomplete combustion for some reason that produces first CO and then in worse cases just carbon particles. If its properly set up the same applies to your heater.

 

The majority of petrol engines throttle the air inlet so the petrol-air mixture is one that will ignite from a spark and burn but not explode so there is far less air and thus oxygen in the cylinder making it far easier to produce CO.

 

There are some old diesels that use a throttle butterfly and those will tend to produce more CO and a few direct gasoline injection petrol engines have been produced that may, if very well maintained, produce less CO.

 

 

 

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Thanks Alan and Tony,that is probably why there was a push for diesel cars,less greenhouse gases.

My worry is sleeping with the heater on.Being naturally cautious I warm the cabin for an hour or two before turning in and switch the heater off to sleep.But on my last trip,I got up for a pee at 3am and it was perishing!

Just googled 12v heaters,and there are some 150W ones quite cheap.

Would a 150W heater flatten the battery overnight?

,

 

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6 minutes ago, Mad Harold said:

Thanks Alan and Tony,that is probably why there was a push for diesel cars,less greenhouse gases.

My worry is sleeping with the heater on.Being naturally cautious I warm the cabin for an hour or two before turning in and switch the heater off to sleep.But on my last trip,I got up for a pee at 3am and it was perishing!

Just googled 12v heaters,and there are some 150W ones quite cheap.

Would a 150W heater flatten the battery overnight?

,

 

 

150w would take about 15 amps from your batteries (if tou are talking about a 230v heater, or 12 amps for a 12v heater)

Leave it on for 10 hours and you would take 2x 110AH batteries below the recommended state of charge. One battery would be destroyed.

 

I think you will find that a GRP boat 'leaks a lot of heat' and 150w is not much more than a couple of light bulbs, it will not heat your boat.

I find a minimum of 700w will just about maintain the room temperature (70Ah = 700Ah over 10 hours)

Electric heating is totally impractical unless on a shoreline hook-up.

 

Use your diesel heater (assuming it is a properly installed marine type and not a 'truck heater' off ebay) and mount your CO alarm at pillow height next to your bed - it then senses the air you are breathing and if it goes off, you'll wake up.

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6 minutes ago, Alan de Enfield said:

 

150w would take about 15 amps from your batteries (if tou are talking about a 230v heater, or 12 amps for a 12v heater)

Leave it on for 10 hours and you would take 2x 110AH batteries below the recommended state of charge. One battery would be destroyed.

 

I think you will find that a GRP boat 'leaks a lot of heat' and 150w is not much more than a couple of light bulbs, it will not heat your boat.

I find a minimum of 700w will just about maintain the room temperature (70Ah = 700Ah over 10 hours)

Electric heating is totally impractical unless on a shoreline hook-up.

 

Use your diesel heater (assuming it is a properly installed marine type and not a 'truck heater' off ebay) and mount your CO alarm at pillow height next to your bed - it then senses the air you are breathing and if it goes off, you'll wake up.

Is there any way of identifying which type our (or any one else's for that matter) Webasto is ?   Will it be labeled or stamped ?  Will the model no. or serial no. give the necessary clue etc    Thanks

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CO detectors will trigger in minutes with high concentrations but won't go off for hours with a very low and less dangerous level. If you left it near the exhaust long enough it should go off

 

https://www.kidde.com/home-safety/en/us/support/help-center/browse-articles/articles/what_are_the_carbon_monoxide_levels_that_will_sound_the_alarm_.html

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15 minutes ago, D Ash said:

Is there any way of identifying which type our (or any one else's for that matter) Webasto is ?   Will it be labeled or stamped ?  Will the model no. or serial no. give the necessary clue etc    Thanks

 

 

It would normally have some sort of label or plaque with type / model / serial number - see picture.

 

Your model number will give the type.

The serial number could probably be cross referenced by a Webasto dealer.

 

What are you trying to achieve ?

Screenshot (311).png

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4 minutes ago, Alan de Enfield said:

 

 

It would normally have some sort of label or plaque with type / model / serial number - see picture.

 

Your model number will give the type.

The serial number could probably be cross referenced by a Webasto dealer.

 

What are you trying to achieve ?

Screenshot (311).png

We had a "second-hand" one fitted 18 mths ago but have no idea from where it was sourced.  And having just yesterday read on another thread that CO from truck heaters can vent through the open engine hole whereas this cannot be the case with a boat it set me wondering.  Not at the boat now but will check what type ours is when next onboard

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9 minutes ago, D Ash said:

We had a "second-hand" one fitted 18 mths ago but have no idea from where it was sourced.  And having just yesterday read on another thread that CO from truck heaters can vent through the open engine hole whereas this cannot be the case with a boat it set me wondering.  Not at the boat now but will check what type ours is when next onboard

 

 

Have a look at the exhaust silencer, if it is a pressed-steel in two halves with a small hole  (only a couple of mm) in the underside then that is definitely an automotive exhaust and should not be used on a boat.

Have a look on the Webasto webiste to see what a 'marine exhaust kit' should look like.

 

It could be an automotive version that has been correctly fitted with a marine exhaust kit (so it is unlikely to kill you) but has not had its electronics reprogrammed, and may become difficult to start unless the boat engine is running.

 

The other problem with automotive ones is that the electronics is set up for use on car batteries which are normally at a far higher charge level than boat batteries.

A car battery is used for 'seconds' only to start the engine and is fully recharged in a matter of minutes and is (almost) always at around 12.7+ volts.

A boat leaisure battery bank will rarely be fully charged and often will be around 12.2 - 12.4 volts (or lower), when the heavy draw of power (used to fire up a Webasto) is experienced it can pull the battery voltage down to low levels where the heater will not function correctly.

 

 

An example (other shapes available) of a typical automotive exhaust :

 

Steel, Stainless, mufflersilencer, Stainless Steel

 

 

 

 

 

The Webasto Marine exhaust kit :

 

 

 

 

 

 

Screenshot (313).png

Edited by Alan de Enfield
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1 hour ago, Alan de Enfield said:

 

 

Have a look at the exhaust silencer, if it is a pressed-steel in two halves with a small hole  (only a couple of mm) in the underside then that is definitely an automotive exhaust and should not be used on a boat.

Have a look on the Webasto webiste to see what a 'marine exhaust kit' should look like.

 

It could be an automotive version that has been correctly fitted with a marine exhaust kit (so it is unlikely to kill you) but has not had its electronics reprogrammed, and may become difficult to start unless the boat engine is running.

 

The other problem with automotive ones is that the electronics is set up for use on car batteries which are normally at a far higher charge level than boat batteries.

A car battery is used for 'seconds' only to start the engine and is fully recharged in a matter of minutes and is (almost) always at around 12.7+ volts.

A boat leaisure battery bank will rarely be fully charged and often will be around 12.2 - 12.4 volts (or lower), when the heavy draw of power (used to fire up a Webasto) is experienced it can pull the battery voltage down to low levels where the heater will not function correctly.

 

 

An example (other shapes available) of a typical automotive exhaust :

 

Steel, Stainless, mufflersilencer, Stainless Steel

 

 

 

 

 

The Webasto Marine exhaust kit :

 

 

 

 

 

 

Screenshot (313).png

I run my diesel heater without the silencer.The exhaust is connected straight to the hull outlet.Have tried it with the silencer,but found next to no difference in the noise level.

It whistles a bit on the start up cycle,but on it's cruise setting (low heat) the fan is inaudible.Just a steady thud thud from the fuel pump.

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3 hours ago, Mad Harold said:

In Wickes recently,saw that they had on offer a smoke alarm and a carbon monoxide detector,both decent makes (Fireangel and Honeywell)

Decided to treat the boat to them as the ones fitted have been on for several years,and as there is a diesel heater fitted,I thought it a good idea.Testing the carbon monoxide detector by the test button and also holding it to the car exhaust (petrol) it sounded off.

However holding it to a diesel exhaust,not a peep.

There appears to be not enough carbon monoxide in diesel exhausts to set the alarm off.

In the event of my diesel heater exhaust leaking,apart from the smell (if I am awake) what other warning is available?

I just read a report of a CO monitor alerting the owner to a problem traced to a broken Eberspasher exhaust

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  • 2 weeks later...

When my Webasto Thermo Top C diesel heater developed a fault it filled the boat with CO. We have three CO monitors and they were all set off at different times, sometimes two at a time. However, I've been told that normally a Webasto doesn't produce much CO, so maybe, if your CO monitors aren't detecting CO from your heater, then it's not that they are inadequate, but that your heater is in good condition. I can confirm though that the alarms are not set off immediately. They seem to wait until a certain limit of CO exposure has been reached. One of my alarms shows the part per million on a digital screen, which is reassuring when it shows 0 and gave me the impression that it's not the level of CO (at low levels) that triggers the alarm, but rather the amount of exposure to CO over time. For peace of mind, multiple CO monitors helps.

Edited by Rick P
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On 08/05/2021 at 10:51, DaveP said:

Check the BS marking of the CO alarm - there are two variants, only one of which satisfies the BSS.  See https://www.boatsafetyscheme.org/stay-safe-advice/carbon-monoxide-co/co-alarms-save-lives/

 

 

I think if you read your attachment you will find your statement is not quite true.

 

 

On 08/05/2021 at 10:31, Mad Harold said:

Thanks Alan and Tony,that is probably why there was a push for diesel cars,less greenhouse gases.

 

 

 

 

carbon monoxide is not a greenhouse gas. 

a diesel will produce more CO2 (per gram of carbon burnt) than a petrol engine (where incomplete combustion is the norm), so a diesel will produce MORE greenhouse gas.

Edited by Murflynn
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16 minutes ago, Murflynn said:

 

I think if you read your attachment you will find your statement is not quite true.

 I sit corrected - but it is recomended over the '-1' certification.

Edited by DaveP
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3 minutes ago, DaveP said:

 I sit corrected - but it is recomended over the '-1' certification.

 

Something is better than nothing, but the correct one is better than 'something'.

 

As I understand it there is little or no difference between the two types, simply that the manufacturers of the 'boat approved' type have paid & submitted their monitor to be tested to 'boat specifications'.

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On 08/05/2021 at 10:58, roland elsdon said:

We have the ones that show peak co over a seven day period too.

its an interesting check. Evidences they are working as well. Our peak was 20 ppm  last week stove lit and cooking in a small cabin.

we have the old ones at  nose height in bed.

CO is slightly lighter than air, so I have always assumed that higher is better...

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2 minutes ago, Cheese said:

CO is slightly lighter than air, so I have always assumed that higher is better...

But the CO is mixed with the other products of combustion which are mainly nitrogen and water vapour and unburnt oxygen so the lower density of the CO being measured in part per million has no impact at all, the CO can not rise all on its own. The advice is where you are protecting in the cabin against CO being produced by a stove or cooker where the burnt gas will be warm, then mount them high as the warmer burnt gas is lighter. However, where you are using them to protect against ingress of CO from an engine or heater exhaust from outside passing though door vents etc. then the detector should be mounted at the height you breath at because the burnt gases will be cooler by time they get into the cabin and they will have pretty much the same density as air. If you have a CO detector in the bedroom, then it should be placed about gunnel height is this is the level of your pillow.

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2 hours ago, Cheese said:

CO is slightly lighter than air, so I have always assumed that higher is better...

Very, very slightly : 28.01 g/mol, same as Nitrogen which makes up about 4/5 of free air. Oxygen at 32 g/mol , CO2 at 44 g/mol doesn't collect in the bilges ...

 

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2 hours ago, Cheese said:

CO is slightly lighter than air, so I have always assumed that higher is better...

 

We always have ones with a digital readout and the instructions have always said to place at height where the digital read out can easily be read. As others have said CO mainly 'mingles' with air rather than rising above it so higher isnt necessarily better.

 

I must get the one in our caravan moved a bit lower as this hasnt been adhered to when it was made.

 

LPG of course is completely different and will gravitate to the lowest point in the boat, building up from there.

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