Gas alarm - CO detector or not what'ya reckon?

Angele

Angele

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Had a gas engineer inspect my camping gaz system, replace hoses and service the oven. All fine.

But, he told me the gas sensor wasn't working and the model (plastimo!) isn't made any more. He has recommended a company called Nereus, based in Poole. They make a range of detectors starting with a "basic" single gas sensor, working up to multiple sensors and the ability to control the flow mechanically. Some of their models also have carbon monoxide detectors. Cost differential between basic gas only model and one with a CO detector is about £85 inc. VAT.

Now, I'm pretty safety conscious, but have previously thought a CO detector to be a bit OTT (I don't have one at home, but then again the gas boiler is serviced regularly). I'm now faced with having to replace the gas alarm, so should I consider one with CO detector too?

Equipment on board that burns fossil fuels comprises: eno 2 hob + oven cooker, webasto heating and, of course, the diesel engine.

Who would suggest going for the basic gas only model, and who the combined gas and CO?

Deciding where to put the gas alarm is easy - next to the shut off valve in the locker under the oven. Not so a CO monitor, if the cause of CO production could be any one of three devices. Also, whereas gas is heavier than air, CO is (slightly) lighter, so it is not immediately obvious where to put it. Thoughts?
 
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When I last looked into it I learned that the available gas detectors were considerable less sensitive than the human nose. Although gas collects in the bilges (and while you don't often put your nose in the bilge, you can put a gas detector there) I concluded that having one wasn't much help unless you have it linked to a mechanical shut-off. This would protect the boat in the event of (1) you had a gas leak while you are away and (2) you forgot to shut off the gas manually before you went away. And I reckoned I was pretty reliable about shutting off the gas.

Carbon monoxide, on the other hand, does not smell, and kills people, often without the victim noticing. Last winter I was on board doing some jobs. It was cold and the battery was too flat to run the Eberspacher, so I am ashamed to admit that I lit the oven. Reading a manual, I nodded off. I reckon the CO alarm saved my life.

Edit: the CO alarm is mounted in the saloon between the windows.
 
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Danny Jo said:
When I last looked into it I learned that the available gas detectors were considerable less sensitive than the human nose. Although gas collects in the bilges (and while you don't often put your nose in the bilge, you can put a gas detector there) I concluded that having one wasn't much help unless you have it linked to a mechanical shut-off. This would protect the boat in the event of (1) you had a gas leak while you are away and (2) you forgot to shut off the gas manually before you went away. And I reckoned I was pretty reliable about shutting off the gas.

Carbon monoxide, on the other hand, does not smell, and kills people, often without the victim noticing. Last winter I was on board doing some jobs. It was cold and the battery was too flat to run the Eberspacher, so I am ashamed to admit that I lit the oven. Reading a manual, I nodded off. I reckon the CO alarm saved my life.

Edit: the CO alarm is mounted in the saloon between the windows.
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Thanks Danny for that eye opener.

The gas sensor is currently right next to the gas valve and both are inside a small locker below the oven, from where it could spill down into the bilges unnoticed. So, I reckon the gas detector would detect a leak long before my nose could, but I take your point.

CO is, as you say, odourless. But, which of the three appliances should I worry about most? (The webasto is in a cockpit locker. So, any build up of CO in there would not immediately flow through into the saloon/cabins. But, it is not well vented either, so I reckon it would get through eventually).
 
My in laws died from CO poisoning in an apartment in Portugal - the silent killer.

We have standard battery powered Kidde CO alarms in the saloon and in all cabins below knee height. £12.95 from Asda including the battery. Main gas supply is switched off at night.
 
robinwr said:
My in laws died from CO poisoning in an apartment in Portugal - the silent killer.
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My commiserations.

... I can see which way this is heading. Two responses and both would suggest I'd be mad not to splash out on the extra £85. What price a life or three?
 
Definitely go with the Gas and CO version. You'll have to compromise on location and I ended up mounting mine at floor level below the cooker (about 2 feet away from the source of both gas and CO).
 
My only comment is sensor location, lpg should be low and CO higher, so perhaps a combined sensor has less value than independant ones. We had a gas sensor below thw cooker and the CO in the tunnel to the aft cabin. In the house the CO is in the lounge where the log stove is and the lpg is beside the cooker in the kitchen
 
maxi77 said:
My only comment is sensor location, lpg should be low and CO higher, so perhaps a combined sensor has less value than independant ones. We had a gas sensor below thw cooker and the CO in the tunnel to the aft cabin. In the house the CO is in the lounge where the log stove is and the lpg is beside the cooker in the kitchen
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The Nereus models are quite good in that regard. Each sensor is separate from each other and from the alarm itself. So, I can fit the unit in the corner where the current one it, the gas detector beneath the oven and the CO detector ...... errr ..... somewhere else. Haven't decided where yet.
 
Regardless of whether you think you need a gas detector or think that a good installation, correct use and a good sniff are enough (at this point I remember that my crew has no sense of smell at all); you DO need a CO detector, which is cheap and easy to install.
 
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blackbeard said:
you DO need a CO detector, which is cheap and easy to install.
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Yes, I think any doubt I had as to their necessity has disappeared.

I also think I'm going to go with a separate battery operated one (one of the Kidde ones?) that can be easily fitted in the saloon or master cabin, separate from the Nereus gas alarm.
 
blackbeard said:
Regardless of whether you think you need a gas detector or think that a good installation, correct use and a good sniff are enough (at this point I remember that my crew has no sense of smell at all); you DO need a CO detector, which is cheap and easy to install.
Click to expand...

Your nose is never enough, you can lose your sense of smell for all sorts of reasons aand some of us have a very poor and intermittant sense of smell at the best of times. For what it costs fit the alarm.
 
The instructions for the Fire Angel CO detector say if you only have one, it should be near where your heads are when sleeping. Ours is on the wall, just above the pillows.

A gas detector should be low down as LPG sinks in air.

Given the above, hard to see the sense of a combined detector, unless it has separate sensors.
 
Richard10002 said:
The instructions for the Fire Angel CO detector say if you only have one, it should be near where your heads are when sleeping. Ours is on the wall, just above the pillows.

A gas detector should be low down as LPG sinks in air.

Given the above, hard to see the sense of a combined detector, unless it has separate sensors.
Click to expand...

... The Nereus ones all have separate sensors.
 
I had a CO alarm last winter. A Kiddie one. What it taught me was that the diesel stove produces no CO in the cabin, and the primus does. After that it was useless and a pain in the arse as it kept going off when I was cooking so I took the batteries out and won't be having one again.

I would not feel safe aboard a boat without a gas alarm though. Doesn't matter how good you think your installation is you are still essentially carrying a bomb in the aft locker.
 
Woodlouse said:
I had a CO alarm last winter. A Kiddie one. What it taught me was that the diesel stove produces no CO in the cabin, and the primus does. After that it was useless and a pain in the arse as it kept going off when I was cooking so I took the batteries out and won't be having one again.

I would not feel safe aboard a boat without a gas alarm though. Doesn't matter how good you think your installation is you are still essentially carrying a bomb in the aft locker.
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Primus type stoves are standard in the Antarctic, and a lot of work has been done on their CO emissions. Basically, a primus type stove WILL emit CO, and it has to be kept in good order, clean and operated correctly to minimize this. Note that altering the space between pan and burner can result in excessive emissions! The emissions are below safety limits if the stove is well-maintained and kept clean, but even slight failures of maintenance can result in harmful levels being emitted. A CO detector is essential, and has saved many lives.

For this reason, I'd be reluctant to have a Primus on board - CO is a far greater hazard than gas, and Primus type stoves emit it even when being used as safely as possible. I also have a CO detector; it has gone off once when we had a faulty burner on the cooker, but usually reads 0. I've never considered a gas detector; I can smell gas, though I do understand that there are plenty of people who can't, and such people should, of course, fit a gas detector.
 
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I can also smell butane or propane, but that doesn’t mean that I will always smell a gas leak. That’s because, being heavier than air, it will sink to the bilges where it will be below the level of my nose.
 
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