On Wednesday, August 5, 2020 at 5:33:52 PM UTC+1, fred wrote:
On Wednesday, August 5, 2020 at 4:17:19 PM UTC+1, Roger Hayter wrote:
fred wrote:

I bought one of these from Amazon
https://www.amazon.co.uk/gp/product/..._b_asin_title_
o07_s00?ie=UTF8&psc=1 It arrived with no wiring diagram. a
href="https://ibb.co/YXqhst7"img
src="https://i.ibb.co/xYR6TMS/gas-detector.jpg" alt="gas-detector"
border="0"/a It will be wired into a 12v system on a boat. Where do I
go from here. (I hadn't realised it was coming from China or I would have
shied away)

The description says: "12V model with non-polarised (reversible) power
terminals for easy wiring ". It also says it has a "relay output".
II should guess the red and black for power leads and the other three
connect to single pole double throw relay. You might need to connect
it to a power supply and expose it to gas to be sure which two represent
the n/o contact. Or you could just join the two which are currently
shorted together and use with the one that isn't for a normally open
switch if you need one.
--

Roger Hayter

Thanks for the help I had guessed what the red and black were but the others confused me, Sounds like I couldn't do it much harm