Bedroom radiator emits strong smell

Greetings everyone,

I live in a small building. My unit has 1 bedroom. The bedroom radiator has been inoperable for over 10 years. The living room rad has operated just fine in that time. It is a cast iron base board radiator powered by hot water. Not steam.

This past summer a plumber was dispatched and he was able to turn on the bedroom radiator. This fixed the issue regarding not having heat. In the fall it began to radiate heat. There was no smell at that time. Very briefly for one day or so a faint smell was there. But it went away immediately.

Since the real cold began in December. The bedroom radiator emits a very strong odor. I contacted the plumber who got the rad working. He advised me to use compressed air. Or to let it burn through whatever had accumulated for 10 years of not functioning.

After 4 weeks. Where the smell did not get any less intense. I used a compressor and blew out that radiator. When I started forcing air through it. Silver foil and also black backing paper which was situated behind the silver foil started to come out. I also forced 2 large clouds of dust out on both ends of the rad.

After that one session. The smell became somewhat less in concentration. I decided to blow out the rest of the silver foil and black backing paper. This also reduced the concentration. I then scraped the bits left near the top.

So at that point looking into it visually. It is just wood back there. With some small spaces between the wood where drywall is seen. Other than that it is essentially empty.

The smell is greatly reduced. But is still off gassing something as it is not a clean smell in the bedroom.

I have spoken to a few people on this issue. Which made me think to turn to the forums to get some kind of help. As this matter is now ongoing and I have no way of isolating what the smell could be.

People have asked me if there are any leaks. Either from the rad or bleeder valve. I can confirm that there is no leak whatsoever. There is carpet in both the bedroom and living room area. The carpet is not too dark. So any leak, especially that black water running through the heating system in our small building would show up on the carpet. I also left paper around the pipes to see if anything leaked and it was dry.

The smell disappears when the heat is off. So it cannot be mold.

The very frustrating thing about this scenario is that the materials in both the bedroom and living room are identical. Both radiators were painted with the same oil based paint. Both living room and bedroom have the same carpet. The living room radiator does not emit any kind of smell whatsoever. And yet if I look inside with a flash light it has that silver foil and black backing paper. But does not smell at all.

Which brings me to the very heart of this problem. If both rooms have the same materials surrounding the radiators. And seem to be painted the same. Likely installed by the same people at the same time as radiators are identical. Meaning one is not any newer in terms of model or make.

For some unknown reason the bedroom radiator emits a strong odor when the heat goes up. It is much less now that I used the air compressor. But not enough to breathe it in. I do not know exactly what is in the air but it does not smell to me to be safe to inhale for prolonged periods of time.

I have had contact with one person from another site. He keeps saying there must be a chemical or pesticide used on the bedroom rad. That does not seem likely. Pesticide was not used. As for chemicals. That I am not certain about. Both rads look the same to me and have the same surrounding materials.

Now the bedroom rad has no silver foil or black backing paper inside. And I am trying to isolate what that smell could be. And then take some kind of action to lessen it. But I cannot understand what is heating up and emitting that smell?

Cannot be mold. Otherwise smell would not disappear with the heat off. Is not a leak, as that would show. Also a leak would smell even with the heat off. Carpet goes underneath the rad. But carpet is in the living room as well and no smell at all there.

Can wood or dry wall cause this sort of smell when heated?

How does a person go about isolating a smell? I cannot think of a logical way to approach this problem. I forced air through that rad thinking it would improve the smell. And it worked to reduce the concentration of the smell. But did not get rid of it. It is much less now but even at let's say 7% concentration, that room is not likely safe to sleep in.

Hence my turning to the forums in the hopes that someone with experience could point me in the right direction. As I have researched this endlessly. And am no closer to finding a solution.

Any feedback or assistance would be immensely appreciated. Thank you.