Whistling from mysterious hole

ecorey

A few years ago we had all of our radiators removed and refinished, including a spare radiator that was left by the previous owner in the garage. Lo and behold, this winter one of the downstairs radiators irreparably cracked. The spare radiator was very close to the previous one's size and shape, so it was installed. As part of the installation the air vent was replaced. At first everything seemed to be working well, but after a while I noticed the radiator started making a small whistling noise whenever the boiler fired. After hunting around I found a small hole in the paint of the "top knob", I guess you would call it. (Obviously still learning about these systems!). The paint in that area doesn't look disturbed, like the hole wasn't painted over on purpose. When I put my finger over the hole, the whistling stops. None of the other radiators in the house have this. Is this hole deliberate or a sign of an issue? Is there a way to stop the whistling?

MaxMercy

Thank goodness the text cleared up the title...

Jamie Hall

Plug up the hole with something. You don't need it. Painter's putty? Something like that...

HVACNUT

Does the cracked radiator have the same plug?

Big Ed_4

That plug looks odd , I wonder if it was designed as a vent when new ...

DanHolohan

Looks like an American Radiator Company In-Air-Rid vent. The vent mechanism is inside the radiator. https://heatinghelp.com/assets/documents/360.pdf

bburd

Is there a separate air vent on the radiator? If not, that hole is part of a built-in vent. If it does not emit steam, leave it alone.

Big Ed_4

I can figure out why it never became main stream

Steamhead

DanHolohan said:

Looks like an American Radiator Company In-Air-Rid vent. The vent mechanism is inside the radiator. https://heatinghelp.com/assets/documents/360.pdf

This.

mattmia2

Dan just posted the patent, not his story about it:
https://heatinghelp.com/dead-men-tales/the-hidden-air-vent/