Rotten egg smell coming from radiators

[StuffezLaBouche]

(reposted as this is more appropriate board)

Hi I would really appreciate some help.
This morning I came down to an appalling smell which I've tracked down to the radiators. I thought it was sewage at first, but I think it's coming from the radiators themsleves. Can anyone advise what this could be and how to fix it? I rent my house from an agency.

Thanks

Cant help with anything specific i'm afraid but this also happened to my bathroom radiator and a few days later my central heating and hot water wouldn't work!! It was something to do with the pressure gauge that had gone to zero. We put it back up to 1 as it should be ( this was last night) and got the heating and water back on. Woke up this morning to no heat or water and the guage back on zero!! My nephew is a plumber and to cut a long story short, he thinks there may be a leak and the smell may suggest it's coming from bathroom radiator......might be totally unrelated to your prob but nay be worth checking the pressure guage on your boiler.

Goddddd! Thanks tibywibs. I wouldnt have a clue where to look on the boiler - it doesn't appear to have any gauge that I can see. The smell has subsided a bit and seems to come in...waves.
Might put the heating on and see if that does anything.

If you bleed the radiators does the eggy smell come out?

Most likely to be hydrogen sulphide that you are smelling. If so, it means that you have bacteria in your central heating system. As well as the bad smell it will be causing some serious corrosion.

If so, I think that fernox sell stuff that will control the microbes. It will depend how bad it is, though, as it's possible that you will also need to drain and flush the system.

OH bloody hell! I have the key to bleed them, but embarrassingly, I cannot find where to use it. The radiators are fairly ancient. I've never bled a radiator and do not have any friends round here either. Is this something I can do myself, or do I contact letting agency?

must be leaking. Otherwise you would not be able to smell it even if it was full of gas.

might be the bottom seam rusted through, might be one of the valves, might be the bleed screw on the side at the top, which is where you use the bleeding key to turn the little quare pin just a turn or so. Don't unscrew it all the way out.

tie a bit of kitchen roll round the pipes under each of the valves, and lie a strip under the whole radiator. Look for drips or wet patches.

Thanks PigletJohn! I am trying in vain to find the hole that the bleeding key thing will fit into. It's not a nice simple on the wall radiator, there are bits cut of the surrounding wall to accommodate pipes, etc.
I will have one big hunt when I've finished current job because I cannot sit in this stench any longer. If no joy I will have to take advice from the letting agency.

Oh, sorry, I think I misunderstood your first post. I thought you were the LL not the renter! In which case, yes, it's very possible that the smell is coming from the radiators. If it is, you aren't going to be able to fix it yourself - so definitely contact the letting agency!

feel the carpet underneath.

and get on with the kitchen roll thing.

The carpets or flooring will be destroyed by a leak, and maybe the downstairs ceiling too.

So this morning there was not a drop of wet on the kitchen roll, or the towels I put underneath. Furthermore, the smell is entirely gone. I can't even catch a little hint of it. If my friend hadn't been here to take the piss help me yesterday, I'd think I had imagined the whole thing. I think I will cross my fingers for now, and if it happens again I will contact letting agency.
Thanks all!

Do you have a blocked up fireplace by any chance ? and did the smell occur after a shower of rain as if water gets down a chimney into a bricked up fireplace it will mix with soot giving an ammonia smell not unlike window cleaning liquid.

See what you mean, bureni, but no - I don't have a fireplace. The smell was definitely located to one particular radiator. It was vile!

As my username suggests I'm not the brightest, can the smell be bled from the system or would flushing the system entirely be a better call? Homeowner from across the pond if that helps matters

Also see I'm 10 years late asking this query here, if anyone replies I owe you BIG.

Hi there. Almost three years now since your last post. We've just renovated our house and noticed that one radiator we put back is stinking too. Did you find a solution after 13 years?

Radiators are waterproof and airtight, so unless it is paint or other coating, you must have a leak.

Feel the welded seams, especially on tbe bottom, and the joints in the pipes and at the fittings.

Feel the carpet under the radiator.

Bacteria from stagnant water in the radiator
This can damage the boiler

Suggest bleeding it and if that doesn’t work
try draining the rad or do a power flush of the whole system.

Bleeding the rad is removing air, not water which is carrying the bacteria
Probably louds of sludge at the bottom of the rad
so

Overall it’s better to flush the system out

edited as I’ve realised I’ve responded to a post from 2023 🤣🤣🤣hope you sorted those rads Chav 😁
and a Happy new Year 2024, 2025 and 2026 !!

Def contact letting agency

Oh god. 13yrs old

🙀🙀🙀😂😂😳😳😳

I found the cause. During the renovations, an electrician has drilled a hole through the wall about 5 inches away from the radiator to run new electrical wiring and a connection for an EV charger. Because an old sewer drain that was no longer in use was exposed, he decided to disconnect it, as we installed a completely new connection instead. Unfortunately, the old pipe—although sealed with a screwed-on cap—is still connected to the main sewer. According to our plumber, this causes overpressure during rain and airflow through the drilled hole, which is located about 3 inches above the pole pipe. Due to the warm air inside and the cold weather outside, this creates a kind of natural convection that pulls the stench from the old pipe into the house through the drilled hole. As it is currently freezing and snowing outside, there is not much we can do right now. However, once the weather allows me to work the soil, I will dig up the pipe and permanently resolve this issue.