Gas alarm - at what price?

skyflyer

skyflyer

Well-Known Member
Joined
26 Jan 2011
Messages
1,433
Location
Worcester, UK
Visit site
Any recommendations - seems I can pay between £60 and £600. Unfortunateley I find that it isn't always true that you get what you pay for.

The lowest point of the bilge is under the saloon sole plate. The bilge pump (via float switch) keeps the level down to dregs so presumably the sensor is fitted close by there. This would leave a 4ft cable run to where the alarm could be mounted and hot-wired to the battery via the electric panel.

Sounds a simple enough job to me - which probably means I've missed something?
 
skyflyer said:
Any recommendations - seems I can pay between £60 and £600. Unfortunateley I find that it isn't always true that you get what you pay for.

The lowest point of the bilge is under the saloon sole plate. The bilge pump (via float switch) keeps the level down to dregs so presumably the sensor is fitted close by there. This would leave a 4ft cable run to where the alarm could be mounted and hot-wired to the battery via the electric panel.

Sounds a simple enough job to me - which probably means I've missed something?
Click to expand...

Cannot comment on whether to pay £60 or £600 ( although £60 sounds cheap )

Remember many if not all sensors are likely to be damaged by water.
A dual sensor system might be sensible. One in the bilge, but well above bilge water level and one a little above cabin sole level close, to the galley area where it wont be damaged by water but could give an early indication of a gas escape into the cabin before it percolates into the bilges.
 
Have 'German Shop' gas detector that works off 12v and has been wired in for some time [5 seasons] Cost about £15. Test it regularly with an unlit gas lighter.

Sort of hope it never needs to work, but it might if necessary
 
Gwylan said:
Have 'German Shop' gas detector that works off 12v and has been wired in for some time [5 seasons] Cost about £15. Test it regularly with an unlit gas lighter.

Sort of hope it never needs to work, but it might if necessary
Click to expand...

The chance of you ever having to rely on it are almost zero. Statistically, it doesn't really matter whether it works or not. On that basis I'd go for cheap, easily replaceable and regularly tested.
 
Oddly enough its not the "live" gas supply that worries me - there is gas locker with overboard venting, the bottle valve, an electric shut off solenoid, the cooker control and the 'flameout' automatic cut off. 5 lines of defence. However we have a spare bottle kept in a lazarette - not ideal I know but this drains directly to the bilge. I have twice now discovered a new bottle where the valve was not fully off and thus only the plastic insert in the threaded connector was preventing a leak. This was 'as delivered' to the shop. I always double check now but I have nightmares about some sort of leak slowly filling the bilge!

This NASA 'splash proof' detector seems reasonable value at £70 and spare detector sensors are available for £12
http://www.allgadgets.co.uk/marine/...ne--p368.htm?gclid=CP_CkaHFsLsCFYhf2wodLjQAWQ
 
skyflyer said:
Oddly enough its not the "live" gas supply that worries me - there is gas locker with overboard venting, the bottle valve, an electric shut off solenoid, the cooker control and the 'flameout' automatic cut off. 5 lines of defence. However we have a spare bottle kept in a lazarette - not ideal I know but this drains directly to the bilge. I have twice now discovered a new bottle where the valve was not fully off and thus only the plastic insert in the threaded connector was preventing a leak. This was 'as delivered' to the shop. I always double check now but I have nightmares about some sort of leak slowly filling the bilge!

This NASA 'splash proof' detector seems reasonable value at £70 and spare detector sensors are available for £12
http://www.allgadgets.co.uk/marine/...ne--p368.htm?gclid=CP_CkaHFsLsCFYhf2wodLjQAWQ
Click to expand...

You store a spare gas bottle in a locker draining to the bilge?? Surely you know this is foolish. Forget about the alarm and just put the bottle somewhere else.
.
 
VicS said:
Remember many if not all sensors are likely to be damaged by water.
Click to expand...
+1
I was told by the manufacturer of my previous gas alarm that the sensors should only be fitted in the bilge if there is no possibility of them getting damp, even from condensation.

I've now got a Pilot alarm, I recall it did well in tests. Sensor is in a locker near the stove, just above the sole.
 
Surprised that no-one has mentioned the need for a carbon monoxide alarm as well.

But then again, CO will only kill you with very little fuss, no bang!
 
skyflyer said:
Oddly enough its not the "live" gas supply that worries me - there is gas locker with overboard venting, the bottle valve, an electric shut off solenoid, the cooker control and the 'flameout' automatic cut off. 5 lines of defence. However we have a spare bottle kept in a lazarette - not ideal I know but this drains directly to the bilge.
Click to expand...

Please, please, please move your gas bottle to a locker that drains overboard, somewhere like the anchor locker.

A friend of mine died along with all but one of her family in a gas explosion on board. One daughter was staying with her friend that night, she woke up to find she'd lost her whole family....it was around this time of year too.

Just in case you're in any doubt of the damage a gas explosion can cause....

 
I have a Nereus alarm because the sensors are waterproof. My bilges are normally dry but you never know what will happen in the future. Earlier this year I found it worked very well when a faulty valve on a new gas bottle allowed gas to flow from the gas locker into the cockpit and then down the companionway into the saloon. My gas locker as built drained into the cockpit but a previous owner had blocked that with sealant and put another drain from the back of the locker out through the topsides. The leaking valve coincided with the sealant plug coming out of the original drain so gas was flowing out of both drains at the same time.
My Nereus alarm cost about £150 three years ago. Plan this winter is to upgrade to a dual sensor version, keeping the existing sensor where it is and fitting the second one in the gas locker as an advance warning of problems
 
nigelmercier said:
+1
I was told by the manufacturer of my previous gas alarm that the sensors should only be fitted in the bilge if there is no possibility of them getting damp, even from condensation.

I've now got a Pilot alarm, I recall it did well in tests. Sensor is in a locker near the stove, just above the sole.
Click to expand...

We also have a Pilot, the dual sensor one. I have one sensor in the bilge but high enough that it shouldn't get wet (if it does we have bigger problems than a gas leak) and the other is directly under the gas oven/hob. I know they work because SWMBOs hairspray and sometimes her nail varnish remover will set them off.
 
On our last boat we had the gas alarm with the white case and twin sensors. Sorry I can't remember the make.
It did its job very well. In fact too well at times. Not only did gas activate it, so did certain cleanining products, flash I think, fruit more than a couple of days old, and making gravy with red wine.
So do fit a handy switch in the live feed to it.

j
 
johnwest said:
On our last boat we had the gas alarm with the white case and twin sensors. Sorry I can't remember the make.
It did its job very well. In fact too well at times. Not only did gas activate it, so did certain cleanining products, flash I think, fruit more than a couple of days old, and making gravy with red wine.
So do fit a handy switch in the live feed to it.
Click to expand...

Just out of interest, in those 3 examples, how did you determine that there wasn't a gas leak?
 
I have had similar issues on other boats with the same alarm. remove the offending item and the alarm returns to normal. The biggest issue is silencing the alarm on a strange boat to enable you to check what the problem really is.

j
 
pvb said:
Just out of interest, in those 3 examples, how did you determine that there wasn't a gas leak?
Click to expand...

In my case we have an electric solenoid at the gas bottle, we only switch it on when using gas and it's switched off afterwards. It was off each time the alarm went off (and had been off for some time). It was abundantly clear what had set the alarm off in each case though we always make a quick check and reset the alarm as soon as the hairspray or whatever has dissipated.
 
I think it was last year that PBO had an article on making a gas alarm - the catalytic sensor elements are a couple of pounds from China on eBay.
 
In the early days of the false alarms on our own yacht checking the bubble tester sited adjacent to the regulator suggested there was no leaking gas. Gas bottles were in a sealed moulding venting outboard.

j
 
You must log in or register to reply here.

Share this page

Top