Do you need a carbon monoxide alarm near a gas fire that hasn’t been lit for 30 years and will never be again?

[chutneystunt]

As subject title! Thanks!

If it has been disconnected by a registered gas engineer then I would say no. If it's still connected and in theory could be lit then I would say yes.

Great thank you. Also if I might ask, I’m having trouble getting to grips with understanding our central heating and hot water system. Boiler is in one room and directly above it on the next floor is hot water tank. I understand there’s no chance of CO getting up there so no need for a CO detector outside the upstairs tank; if you have a minute could you explain to me how it works with the pipes, so how does the CO leak out of the boiler - where ought it to be going, or is it not supposed to be being ‘made’ at all? Is it a gas pipe thing and therefore the upstairs is just supplied with water pipes so that’s why there’s no risk?

Thanks a million if you or anyone can muddle through my confusion!

You will have a gas meter somewhere in your house then a gas pipe will feed both the gas boiler and the gas fire so there is usually a T connector somewhere. You may also have a gas supply to the kitchen for an oven/hob.

In my house the meter is on one side of the house and the boiler on the opposite wall of the house. So the gas pipe can be seen running up the outside of the house to the meter then comes inside but you can't see it because it is in the cavity wall. It then runs under the floor of the bedrooms and landing until it reaches the complete opposite end of the house from where it started goes down the cavity and connects to the boiler.

It tees off (T) under one of the bedrooms to the gas fire in the lounge.

For how a boiler works see this video yours isn't a combi boiler which is the first one mentioned in the video but keep watching.

I have a 4 bed house with 3 reception rooms and only 1 carbon monoxide detector. I have a gas boiler and a gas fire. When I had my boiler serviced the chaps recommended the detector be placed near to the boiler so it is in the room next to it. It is an alarm one so it would wake us if there was a leak.

Wow, thank you so much for that reply! That’s just the level of detail I needed. Really appreciate you taking the time to explain it. I can’t believe it’s something I’ve never given any thought to - it’s only reading your reply and watching the video that I’ve realised why it’s called a boiler - ie it boils water!!!

We’ve put one CO next to the boiler. The fireplace is still connected but as I say not used for decades with no plans ever to. From the diagram attached, is the risk when the flame is lit; also as per your post and cowfacemonkey’s, might the CO ‘backflow’ to a different outlet, say the fireplace, if the flue is blocked, flowing perhaps via that t pipe you mentioned; or is there a valve that shuts off anything escaping from the fireplace; or is it all a lot more complicated than that?!