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Gas Detector Placement


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HI Guys,

 

We are about to install the two gas detectors. They are the type that can shut off the solenoid when they detect gas.

 

The issue is, that the lowest point in the bilge adjacent the stove is wet (see picture) as its a keep stepped mast and there is often some water in there thats not enough to trigger the bilge pump - so the detector cant go there.

 

https://photos.app.goo.gl/z7Fm1y6iRLGdD3n67

 

The area of the bilge before it goes into the keel of the bilge has a hole at the lowest point, so if I were to install the detector there, gas would pass it on the way to the lowest point in the keel - but it would not collect there.

 

https://photos.app.goo.gl/5YKREXBmVGadDPNC9

 

And just for the sake of being complete here is the overall context:

 

https://photos.app.goo.gl/j4MuMYfRUizpCTfg7

 

Would just above that hole in the bilge to the keep area be suitable?

 

I was thinking of the seond detector on the shelf immediately below the oven.

 

Thoughts?

 

AG
 

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For bilge, keep the sensor as close to centre line as possible. And just above the highest waterline the bilge gets too when the pump normally switches on. The sensors don't like water. But the mesh screen on them does keep a fair amount out. Just be prepared that an emergency high water level will mean the possible replacement of the sensor. You just have to comprimise both aspects a tad.
Below the oven is good, but once again, keep out of possible water.

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I personally wouldn’t fit a gas detector that shuts off the solenoid, just one that alarms

Had the following happen on a delivery once.

One day the gas worked, next day no gas but rough weather and no warm drinks or hot food for two days or more, when we got into better weather and warming up we checked turned out that with water sloping around the bilge, still well clear of the sensor, was enough to shut off the solenoid but not enough to activate the alarm.

Right PIA

They sniff really well but I don’t think most are designed for marine use

Best place to install I believe is below the lowest point of the gas line / cooker but as high as possible. They will sniff gas that’s passing, they don’t need to sit in where the gas will settle

Just MHO

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I personally wouldn’t fit a gas detector that shuts off the solenoid, just one that alarms

Had the following happen on a delivery once.

Required for CAT1-2

I wouldn't not have one. If you have a leak, the tank is shut off, leak stops. I had an extractor fan (flame proof) that turned on if the Alarm sounded and evacuated the bilge. Tank off, Fan on. I didn't have to do anything.

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The ones BEP sell have an over ride function for that issue Jon. From memory you hold the test button in for 10 seconds - after ensuring it is a false alarm. I’ve not seen the bep ones shut off without alarming, I’ve seen a heap die from being wet. In theory, the green OK light turns to an orange fault light, rather than the red alarm light. Not sure on other brands.

Only issue then is the electrical solenoid valve failing. May still pay to carry a backup on longer trips.

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The ones BEP sell have an over ride function for that issue Jon. From memory you hold the test button in for 10 seconds - after ensuring it is a false alarm. I’ve not seen the bep ones shut off without alarming, I’ve seen a heap die from being wet. In theory, the green OK light turns to an orange fault light, rather than the red alarm light. Not sure on other brands.

Only issue then is the electrical solenoid valve failing. May still pay to carry a backup on longer trips.

 The BEP sensors are a major pain - any moisture at all will kill them . Have had them fault for no apparent reason too so yes press the override for 12 secs but if you are in a remote place you may need to keep doing this until you replace the sensor if they dont reset on drying out.

 

When replacing my sensor-  rather than re route the new cable that come with the unit which was going to be a major as it goes through some very tight , unaccessable spots I cut the cable near the sensor and soldered the new sensor and sealed . Outcome - it still alarms !!!   It cant be the wire and BEP told me doing what i did should work however an independent contractor told me the sensors are so sensitive that any variation in current like in a solder will send them off.

Looks like re routing the new cable will be necessary which is frustrating .

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Paul, I normally cut and heat crimp the wires near the sensor which has been successful for me.

 

They are very sensitive to water, the way the sensor works dictates that.

 

Some do seem to fail for no reason, normally after a few years.also, the sensitivity of the sensor is calibrated at the factory, it would seem with some variation. I’ve seen them where perfume sets them off.

 

If in a remote place, with a faulty sensor, you could disconnect the sensor from the back of the control, you link the G and B terminals to make the control ignore that input. Same as if you only use one sensor, the second sensor G and B are linked from factory, the link is removed if your using two sensors.

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Paul, I normally cut and heat crimp the wires near the sensor which has been successful for me

 

I will cut and re do - several people had a look at the join I did and commented it looked fine but worth another try .....

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Thanks for all the good tips. I will try to install the detectors this weekend.

 

Very easy to override manually (short two pics) and I think it is mentioned in the manual too about a override function.

 

IT: were you saying the solenoid or regulator fails on the BEP units?

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Solenoid valve. It has a 12v coil, but the controller only provides 12v for about 1/2 a second, then drops back to about 4.5v to keep the solenoid valve open. If the valve is at all sticky, it wont open....

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There is no such reg as far as I can see.  Solenoid valves aren't even mentioned.

The rules (16.09) require for all categories that the installation complies with current regulations.

The regulations require a gas detector. There is no requirement for a solenoid linked to a detector. You can still turn the gas on/off manually at the bottle each time you want to use it.

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The rules (16.09) require for all categories that the installation complies with current regulations.

The regulations require a gas detector. There is no requirement for a solenoid linked to a detector. You can still turn the gas on/off manually at the bottle each time you want to use it.

I’m not being picky but can you show me the regulation that requires a gas detector, as residential installation don’t require this. Is it to do with sleeping in the same space ie boats, motor homes etc as I’ve not struck this in all the safety checks I’ve done and I’ve been involved with a few.

I’ve always believed it was a nice to have rather than a requirement ?

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Dtwo, on 12 Jun 2019 - 6:33 PM, said:snapback.png

There is no such reg as far as I can see.  Solenoid valves aren't even mentioned.

The rules (16.09) require for all categories that the installation complies with current regulations.

The regulations require a gas detector. There is no requirement for a solenoid linked to a detector. You can still turn the gas on/off manually at the bottle each time you want to use it.

Actually you might be correct. There used to be a rule and I think the rule was that in the event of a fire in the galley, you need to be able to turn the bottle off. I think that changed when the new rules of Gas tank placement was changed. My remembory seems to be becoming more foggy as I get older. I need a file clean and defrag.

 

Solenoid valve. It has a 12v coil, but the controller only provides 12v for about 1/2 a second, then drops back to about 4.5v to keep the solenoid valve open. If the valve is at all sticky, it wont open....

 

12V to open, then after 3 secs it drops to 9V.

If the solenoid fails, always test that the solinoid is getting the initial 12V to energise it and then switiching to the 9V. The valve should not be able to get " sticky" but they will not energise with only 9V. However, even not energised, 9V should not be able to burn the coil out.

The 12V for long periods eventually fry the coils. Personally, I think they are over engineered. they don't need such a heavy spring system. LPG is only ruffly 150PSI. I suspect the valve was designed generically and capable of handling much higher gas pressures. A less powerful solenoid would suffice and thus one with a winding capable of handling 12V with no great current draw and thus less heat would work just fine. I am swtich much higher pressures with smaller solenoids in other applications.

 

 

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I’m not being picky but can you show me the regulation that requires a gas detector, as residential installation don’t require this. Is it to do with sleeping in the same space ie boats, motor homes etc as I’ve not struck this in all the safety checks I’ve done and I’ve been involved with a few.

I’ve always believed it was a nice to have rather than a requirement ?

I don't believe there is a rule to have one, but you would be nuts not to have one.

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I don't believe there is a rule to have one, but you would be nuts not to have one.

Some say you would be nuts to have one in a race boat as it would be wet and not working the whole time.

Horses for courses

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