I am renting this apartment, so i rather keep the Work as less invasive as possible.

I have several single pipe steam radiators (could as well be the cast iron type). One of the radiators heats up at the control Steam Valve pipe section that comes in, and at most will barely heat 1 or 2 sections of the total 9 radiator sections.

The radiator was standing flat with no angle to it, so i have added a couple shims to angle the radiator towards the pipe. No change observed.

If i remove the air valve (located on the opposite side of the steam valve, midheight of the radiator), the radiator heats up very slowly, but only about 4 sections get warm. I'm reluctant of keeping the air valvle off all the time.

In sat next to the radiator when it was heating, and did hear a bubbling sound similar to when water drains in the shower.

This makes think that there is water or sludge stock at the Steam Valve. As i mentioned before, i rather not unplug the pipe/radiator, and wondering if there are any simple maintenance steps that potentially can remedy a situation like this?

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  • Removing the air vent is not the way. Replacing it (or asking your landlord to, or POSSIBLY cleaning it in some way) is the way.
    – Ecnerwal
    Dec 26, 2021 at 1:57
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    Well, taking off the air vents and blowing through them works, the air passes. When I rotate the vents with the exhaust hole down, i cannot blow through them. That kinda shows the vent works, no? Also, i placed the vent in a white vinegar for 30-60 minutes, and then washed with cold water and the result was the same. Having the vent on results in minimal sections being warm. Removing the vent heats up most ot the radiaotor's sections. Dec 26, 2021 at 23:26

1 Answer 1


Your problem is not enough vent capacity but is that there is not enough steam being supplied to the radiator. Check the piping from where it takes off from the main steam line to see if anything could be restricting the flow of steam. Is more than one radiator attached to that supply pipe? Does the pipe run horizontal and maybe flow down slightly causing a trap? Is the supply pipe to that radiator too small. (show the size). Is that radiator connected at the end of the main line? If it is, is the main line vented properly. You need more more steam not a larger vent. Make sure that the valve at the radiator is wide open.

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