Steam Trap on Radiator

Jamie Hall

a bad trap. The mechanism that allows air to get out (but not steam) is different from the one that allows water to get out -- thus it is quite possible (in fact, very likely!) that when the trap goes, it will go in just this way.

Fortunately, unless you have something really really strange, it's really easy to open the trap and replace the innards.

Rob Pickard

Steam Trap on Radiator

Is it possible for a thermostatic trap on a two-pipe steam radiator to allow water but not air to pass through?

I'm trying to determine whether my steam trap is the reason that air won't vent out of the radiator, or whether it's that the return line itself isn't vented well enough through the main vents.

If the boiler is on for a long time, the radiator will eventually fully heat, and condensate will drain out of the steam trap to the return line, which makes me think that the trap is not stuck in the closed position.

Big Ed_4

trap

> Is it possible for a thermostatic trap on a

> two-pipe steam radiator to allow water but not

> air to pass through?

>

> I'm trying to determine

> whether my steam trap is the reason that air

> won't vent out of the radiator, or whether it's

> that the return line itself isn't vented well

> enough through the main vents.

>

> If the boiler

> is on for a long time, the radiator will

> eventually fully heat, and condensate will drain

> out of the steam trap to the return line, which

> makes me think that the trap is not stuck in the

> closed position.



Open the trap when cool and see in water drains down. If it does then replace the guts of the trap....

Rob Pickard

What would it mean if water does not drain down when the trap is cool?

Fred Harwood_2

Trap

Where and what is your main vent? Should be by the boiler.

Big Ed_4

Trap not working or blockage.

Rob Pickard

I'm not understanding

Big Ed - Did you mean that if the trap allowed water to drain down there was a problem, or if the trap did not allow water to drain down there was a problem?

Fred - I live in a large old condo building with a shared boiler, and although I've been down to see the boiler I've never been able to find the main vent(s).

Jamie Hall

Almost certainly

a bad trap. The mechanism that allows air to get out (but not steam) is different from the one that allows water to get out -- thus it is quite possible (in fact, very likely!) that when the trap goes, it will go in just this way.

Fortunately, unless you have something really really strange, it's really easy to open the trap and replace the innards.

Rob Pickard

Replacing Hoffman 17C innards

Jamie - When you say it would be easy to replace the innards, do you mean easy like replacing a light bulb? The trap is a Hoffman 17C, which seems like a very common model for which I can buy the replacement thermostatic disc.

I'm not a plumber, so if it requires any special expertise I'd want to call someone for help, but my experience so far is that the heating contractors in the Portland, Oregon area know very little about this type of thing.

Thanks,
Rob

Jamie Hall

not quite

at the lightbulb level, but not too far from it -- there are stores on-line (State Supply? I forget at the moment) which, given the model of the trap -- which you have -- offer replacement innards (float, seats, themostatic mechanism, the works). You unscrew the top (that's where it can get interesting), pop out the old, pop in the new...

tim smith

Consolidated supply in Portland can order you replacement

thermostatic element for that. The rep happens to be in Vancouver also. Columbia hydronics is the Rep. for Hoffman. Good luck, Tim