Help! Hissing Convector Radiator

IndieRevolver

Recently bought a house and this is my first time with steam heat. I had someone come out and service the boiler and fill the tank to make sure everything is working. I turned the heat on today for the first time and everything works great. The only issue is that there is one convector radiator that does not stop hissing. I pulled the cover off and took some pics. It seems to be hissing from the bottom of the silver piece. Can someone advise what needs to be done to make this hissing stop? Do I need to pay to get a professional out or is this something I can do myself?

The silver piece looks like it might be pushed back or slightly bent. I think the cover that is on there is not the one that was originally there and may have bent that piece. 

Also, is there a way to just shut this radiator off, or does it need to be on for the others to work? 

Any help is greatly appreciated. 

ChicagoCooperator

The silver gizmo is the air vent and it looks like it's leaking. Others here can tell you what you should do and if you need to simply remove and put it back or replace it far better than I can.

Also, make sure you vacuum the convector and keep it clean for maximum heat output (and on any other convectors you have).

IndieRevolver

I took a can of compressed air to it after the pics. We had insulation blown in a couple months ago and they started blowing it in there until I stopped them (You can see their hole in the top right of the first pic). We have two convectors and then standard radiators throughout the rest of the house. 

Thanks for the reply! Hoping someone can advise what I should do about this. 

roelandp

shut off boiler remove and install a new one

BobC

That vent is usually sold at big box stores and they are known to be of low quality. Hoffman and VentRite make much better vents, just make sure it has straight threads so it will work for your convector.

Gorton and maid O Mist also make great vents but I don't know tou have room for them.

IndieRevolver

So I removed the old one and noted it had a crack from the incorrect vent cover pushing up against it. 

I ran out to one of the big boxes and picked up this:



I wrapped the threads and tightened it on. I fired up the boiler this morning and it's hissing nonstop still. It's not as loud, but it's still loud and doesn't seem to stop. Is this normal. Apologies for the dumb questions, but I've never had a steam system before. 

mikeapolis

BobC said:

That vent is usually sold at big box stores and they are known to be of low quality. Hoffman and VentRite make much better vents, just make sure it has straight threads so it will work for your convector.

Gorton and maid O Mist also make great vents but I don't know tou have room for them.

Sounds like its not shutting. You mentioned that you've never had a steam system. Have you considered scheduling a tech out to check the boiler. Could you attach some pictures of the boiler?

ethicalpaul

The only vent I ever bought from HD looked just like a Maid o' Mist, but it leaked on the first day. Ever since then I've only ever bought real vents from SupplyHouse.com

IndieRevolver

mikeapolis said:

That vent is usually sold at big box stores and they are known to be of low quality. Hoffman and VentRite make much better vents, just make sure it has straight threads so it will work for your convector. Gorton and maid O Mist also make great vents but I don't know tou have room for them.

Sounds like its not shutting. You mentioned that you've never had a steam system. Have you considered scheduling a tech out to check the boiler. Could you attach some pictures of the boiler?

I had a tech out earlier this week to service the boiler. I popped it on for the first time yesterday and noticed the cracked vent. I've now put the second vent that I got from the big box and it still hisses nonstop.

Video here if it helps: https://youtu.be/JZsHQiFqiLI

Pics of the boiler:

ethicalpaul

Are you sure it's the vent? Gingerly without burning yourself feel around to verify the source of leak.

Also that sounds like way more than the 1-2 psi that your system should be running at. I wonder if your pigtail is plugged up, "hiding" the actual pressure from your gauge and pressuretrol.

IndieRevolver

ethicalpaul said:

The only vent I ever bought from HD looked just like a Maid o' Mist, but it leaked on the first day. Ever since then I've only ever bought real vents from SupplyHouse.com

Is there a specific one needed for a convector radiator? I look up 1/8" steam vent and see multiple options on Supplyhouse.com 

IndieRevolver

ethicalpaul said:

Are you sure it's the vent? Gingerly without burning yourself feel around to verify the source of leak. Also that sounds like way more than the 1-2 psi that your system should be running at. I wonder if your pigtail is plugged up, "hiding" the actual pressure from your gauge and pressuretrol.

The first one was bent and cracked, so the vent was definitely a problem, I don't know if it is THE problem though.

You lost me at pigtail (I'm sorry, this stuff is all super new to me). I will say that when the system is running, it's all very quiet and seems to work perfectly. It's just this one convector radiator that is making any noise. The rest of the place is heating nicely and not making a peep. 

ethicalpaul

IndieRevolver said:

ethicalpaul said:

The only vent I ever bought from HD looked just like a Maid o' Mist, but it leaked on the first day. Ever since then I've only ever bought real vents from SupplyHouse.com

Is there a specific one needed for a convector radiator? I look up 1/8" steam vent and see multiple options on Supplyhouse.com 

There are definitely lots of options. You have to match the thread size (1/4 or 1/8 npt) and you want a "straight" style (since your port is pointed up--many point sideways and they use an angled vent). And for a convector I'd want a nice slow vent. I'm only used to Gorton-style sizing so I don't know exactly the one to tell you, but someone else will.

But let me step back and ask you, did the sound continue even after steam had reached the vent? Or does the sound stop when the steam hits the vent? If it's the latter, then the vent you have may be OK.

ethicalpaul

IndieRevolver said:

The first one was bent and cracked, so the vent was definitely a problem, I don't know if it is THE problem though.

You lost me at pigtail (I'm sorry, this stuff is all super new to me). I will say that when the system is running, it's all very quiet and seems to work perfectly. It's just this one convector radiator that is making any noise. The rest of the place is heating nicely and not making a peep. 

The "pigtail" is the informal name of the 1/4" "syphon pipe" that is the curly pipe on your boiler that the gauge and pressuretroll are connected to.

The pigtail keeps steam away from your controls. But it can get clogged up after a number of years if it's not cleaned out during regular service maintenance events.

If it gets clogged up, then the boiler pressure can climb too high and can damage your vents and cause many other problems. The pressuretrol's job is to turn off the boiler once the pressure reaches a threshold (hopefully about 2psi) and then allow the boiler to run again when the pressure drops to about .5 psi

I recommend this book from this site which will help you understand how this stuff works: https://heatinghelp.com/store/detail/we-got-steam-heat-a-homeowners-guide-to-peaceful-coexistence

Chris_L

So is it hissing air or hissing steam? If air, that is what it is supposed to do.

Usually not that loud. But what kind of main venting do you have? If little or none, the air will vent at the radiators (or convectors) and may sound like that.

IndieRevolver

ethicalpaul said:

ethicalpaul  But let me step back and ask you, did the sound continue even after steam had reached the vent? Or does the sound stop when the steam hits the vent? If it's the latter, then the vent you have may be OK.

The sound is nonstop as the boiler heats up and steam starts circulating. It doesn't stop while it's running. It's only after I turn the system off that the steam stops coming out.

I went down to look while it was running and it seems that the PSI isn't registering on the boiler. 

ethicalpaul

You should clean that pigtail or have it cleaned.

dabrakeman

I would go back to determining whether you have a leak somewhere else in that convector radiator. Maybe in the fitting below the vent. Put a plug in in place of the vent. That way the radiator shouldn't get any steam at all. If it is still hissing then you have a leak.

IndieRevolver

Appreciate all the advice, everyone. Had someone come out today to service the boiler. He replaced the blower motor and fan and flushed the system twice and replaced the offending air vent with an adjustable one. Everything is working perfectly now.