Pilot gas alarm

[nigelmercier]

Yes they are, so it is very strange that a lot of people put them in the bilge.

If you don't mount it low, it may as well not be there.

I discussed this with the technical guy at the company who makes them. He said that on no account should the sensor be put in the bilge, unless the following conditions both apply:

The boat has a very deep or very dry bilge
The bilge has free air flow to the gas pipes, or the gas pipes run through the bilge

On my boat the gas would have to flood over the floor, and drop down a 25mm hole to get into the bilge. The base of an open bottom locker in the galley is a much better place.

 

[auditdata]

I got so fed up with turning the battery switch on/off that I've fitted a separate switch for the alarm

I had a new install and there was no gas on board when it would go off. Replaced the two sensors under warranty and it still sometimes alarms. Also fitted a separate switch. Not a great design for the money!

 

[VicMallows]

Interesting that my £12.99 LIDL gas detector has functioned perfectly for 5 years. No false alarms, but will go off in seconds if you are a bit slow lighting the cooker. They come with a mains cube but actually work on 12v DC (and don't even care about the polarity since they have a bridge rectifier). They work on the hot-wire principle and consume around 100mA. ( I fitted one on a boat which required coding and it was accepted without question.).

 

[maby]

I discussed this with the technical guy at the company who makes them. He said that on no account should the sensor be put in the bilge, unless the following conditions both apply:

The boat has a very deep or very dry bilge
The bilge has free air flow to the gas pipes, or the gas pipes run through the bilge

On my boat the gas would have to flood over the floor, and drop down a 25mm hole to get into the bilge. The base of an open bottom locker in the galley is a much better place.

Not disagreeing with you there - when I fitted one, I put the sensor on a bulkhead just above floor level.

 

[nimbusgb]

Interesting risk profile. One leaves the boat locked up for he week with everything urned off. The first thing we do hen getting o he boat is turn on the electrics and wait for the gas alarm to settle.

If there gas been a gas leak perhaps turning electrics on is not a good idea.

Running a calibration startup sequence in the presence of gas may mask a small leak.

Otoh. If the gas alarm is left on it could spend all week alarming before the battery was flat or the alarm 'expired'.

Hmm.

When I leave our boat, for months at a time, with the gas bottle disconnected completely, I open her up and air her out before turning anything on but that may just dilute any gas down to a combustible ratio!

 

[maby]

Interesting risk profile. One leaves the boat locked up for he week with everything urned off. The first thing we do hen getting o he boat is turn on the electrics and wait for the gas alarm to settle.

If there gas been a gas leak perhaps turning electrics on is not a good idea.

Running a calibration startup sequence in the presence of gas may mask a small leak.

Otoh. If the gas alarm is left on it could spend all week alarming before the battery was flat or the alarm 'expired'.

Hmm.

When I leave our boat, for months at a time, with the gas bottle disconnected completely, I open her up and air her out before turning anything on but that may just dilute any gas down to a combustible ratio!

Definitely! Our gas alarm is always powered on - it's when the boat has been locked up for a week or more that you need it most. I did consider getting one of those hand-held gas alarms that would allow me to do a quick sweep of the boat at floor level before I turn the power on, but came to the conclusion that I would prefer to leave the main alarm on. There has been at least one occasion at the marina when I've heard an alarm going off on a neighbouring boat, got the management to contact the owners, and they have arrived later to find that there actually was a leak!

 

[Tony Cross]

We have an electric gas shut-off valve and the two-sensor Pilot is wired to that. I have one sensor under the cabin sole but well above the floor of the bilge, the other is under the cooker. Ours will go off when almost any aerosol is used inside the boat. SWMBOs hair-spray always sets it off for example!