A couple questions about steam air vents

sjl1222

So I just moved from the South to the midwest into a 2 story home w/ a basement. It has a 100 year old one pipe steam system. I have read so many helpful threads on this site to improve the steam heating, but I still have a couple questions.

1. I've read about the importance of main venting. I looked all over down in the basement and don't see any vents that I can tell. There are several pipes that go from the boiler to different directions through the ceiling, all wrapped in asbestos. I'm not seeing any vents. Would they typically be near where the pipes bend up into the floor?

2. It sounds like it is super important to have main vents, but some websites say they aren't necessary for single family homes. Is this something I should prioritize doing sometime this year?

3. Lastly, all the radiators heat up quite nicely. When it is mildly cold, the whole house warms up pretty evenly. But now, when it is way below freezing for weeks, the second story is about 5-6 degrees warmer than the first story at all times. The current air vents appear to be quite old, all Hoffman 40s, and many of them are hissing and steaming throughout the heat cycle. I figure it's time to start replacing them, so my idea was to replace them with the Varivalves. I would lower the venting when it's very cold outside to keep the upstairs a little cooler, and then I could adjust it back as needed as the temperature outside changes. Does that make sense or am I misunderstanding how the venting works?

Thanks yall, this forum has been incredibly helpful!

neilc

hissing and steaming = yeah, time to replace,
you might try cleaning them first, boiling them in vinegar,
try one first , , ,

but let's get a look at the boiler also,
what pressure is it running at ?
and what's it set to?
how's the water look?
and does it bounce much when firing?

post some pictures of the controls,
and a general shot of the boiler showing the piping also, floor to ceiling.

you're on the right track with slowing down venting where you're hot,
and may not need to reset after it warms up again,
But, main venting in the basement is key, and should be a first priority,

Steamhead

@sjl1222 , main vents are key to good, efficient operation. Where exactly are you located?

sjl1222

I'm in Kansas City. Attached are a couple photos of the boiler, and a bonus picture to see if anyone can tell me what this instrument is hung up behind the radiator.

The pressure on the radiator is set to 0.5 and the dial inside is set to 1. We actually got the boiler itself serviced and cleaned a couple months ago, and the water looks much better now. The boiler hadn't been touched in a decade prior. I keep the water level around half way up the tube, which requires topping off a couple times a week when it's this cold.

I've also removed a couple of the worst offending air vents and I'm boiling them now while I decide which ones to buy for replacements. Lastly, our bedroom radiator bangs loudly, and it seems to have sunk into the wood flooring enough to have the slightest tilt the wrong way, so I wedged two pennies underneath the feet under the vent, giving it the slightest tilt back toward the pipe. I'm hoping to already have a quieter radiator tonight!

sjl1222

Hmm I boiled two of the worst offending air vents and put them back on. They're not hissing and steaming anymore, but now the boiler is short cycling. Pressure raises above 1.5 cutting it off for about 2-3 minutes until it drops back below. Not sure what that's about or how cleaning 2 air vents did it.

Jamie Hall

Depending on when during the call from the thermostat, the rise in pressure may possibly be normal for a somewhat oversize boiler (which is a very common thing!). Cleaning the vents may have allowed them to actually close when steam gets to them, like they're supposed to. Are the radiators warm?

neilc

I was going to say something about having to fill the boiler weekly,
but the vent boil seems to be your answer, a couple a day keeps the boiler doctor away.

sjl1222 said:

Hmm I boiled two of the worst offending air vents and put them back on. They're not hissing and steaming anymore, but now the boiler is short cycling. Pressure raises above 1.5 cutting it off for about 2-3 minutes until it drops back below. Not sure what that's about or how cleaning 2 air vents did it.

Don't worry about the short cycling, yet,
main venting is going to help there.
Boil the rest of the rad vents and be sure the leaking is stopped,
Post a picture of the face and scale of the Ptrol, you may have room to dial it a little lower, gently.
The banging rad,
try lifting gently on the valve end to see if therer's slack and a slump under the floor,
if so, raise the whole rad as much as you can, keeping the vent end slightly higher than the valve end