Problematic vent in Attic Space

mike85k

I have a problematic vent in an unheated attic space. There is a riser that runs from the basement to the second floor, and feeds one radiator, it then makes a turn and runs about 8' through an adjacent unheated attic space. I find it odd that it is only tapped for an 1/8 vent. When we moved in there was a hoffman vent that just spewed out steam and never closed, I replaced that with a Gorton that has since gone bad, and now a maid-o-mist has gone bad. This is a problem because nobody can tell that its leaking until I climb into the attic and see while the system is at full steam.
I'm thinking the more extreme temperature changes are hard on the vents in here and causing them to go bad quickly, I do not have this issue with other vents in the house.
I don't seem to have an excess of pressure as my pressure-tool is set to 1.5 psi, and per my PSI gauge it does cut out around there.

Does anyone have a recommendation for a vent that would hold up better in this space? I was debating about a big mouth since it is a pretty long run to get there, but since its only a 1/8" opening I would need a few reducers and I'm not sure how well that would work. I've also thought about just plugging this tap but since this radiator is actually the first one to heat upstairs and is nice and quiet, there does seem to be value in it being vented.

nicholas bonham-carter

How many ounces is the system attaining during the steam-offs? Radiator vents can only hold so much pressure.
A low pressure gauge would tell that your pressure is too high.
Has the pigtail under the pressuretrol been cleaned lately? If not, then it may be clogged, and allowing the pressure to rise too high.—NBC

Jamie Hall

Is there anything on that riser beyond that one radiator? Or to put it another way -- what if anything is the purpose of that 8 foot run in the unconditioned space? And is that run more or less horizontal? I'm thinking that if condensate gets into that run -- which it will if it's horizontal and vented -- and some gets pushed into the vent -- which it will if the run doesn't have plenty of pitch -- and freezes, you can kiss the vent goodbye.

Is there any reason not to put the vent in the conditioned space?

mike85k

I don't have a low pressure gauge, mine reads 0-15 psi. I don't have an issue like this with any other vents so I don't think it's pressure related, I did clean out the pigtail at the start of winter.
There's nothing else off this line past the one radiator, it is horizontal in the unheated space, I have it wedged up on the far end so that I'd sloped away from that end, before I did that water was getting trapped and it would bang. The only reason I can't put the vent in the conditioned space is that there is no exposed pipe, only the radiator. I am tempted to plug this and put a faster vent on the radiator

Jamie Hall

Don't put a faster vent on the radiator. Instead, is there any way you can put a nice fast vent on the pipe at the inlet to the radiator?

Fred

How long is the pipe from the basement to that radiator? if it is no longer than a typical riser to any other radiator on that floor, I would try plugging it, in the attic and see if the vent on that radiator can accommodate the air in that riser, just like the others already do. You really don't need to vent the air out of the pipe, past that radiator anyway. I'm wondering if someone along the way just decided to vent the pipe because they thought is was the right thing to do. It's no wonder it's the first radiator to heat and is quiet because, probably more often than not, that vent is stuck open, making that the path of least resistance. You really don't care that it is the first to heat, you just want it to heat, along with any others. What size vent do you have on that radiator now? If it is too slow to heat, after you remove the vent in the attic, depending on what vent is on the radiator, you may be able to step it up a little, so long as you don't over do it.

Steamhead

I bet they installed it so you could finish off the attic and put a radiator there................

mike85k

It's the same length as the other riser. The other riser feeds two radiators and they are noisy, I always get hissing sounds and some painting out of then because there is no riser vent. I added a vent in the pipe before the valve on one to help, but they are still the noisy-est radiators in the house. That's my biggest reservation with plugging the pipe, I don't want to create the same issue.
This one has a Hoffman 40 on the radiator, and had a gorton d on this pipe. Unfortunately there is no room between the valve and the floor to add a vent to this one. I'll try plugging the pipe and swapping out the Hoffman for a spare m-o-m I have, maybe a c or d will work well.

mike85k

"I bet they installed it so you could finish off the attic and put a radiator there..............."
We've recently realized that this room was an addition, it's a dormer built into the slope of the house, so all of their must have been added to the original system at some point, so who knows what they were thinking. The space that it vents to is too small to do anything with except for a bit of storage.

Fred

If the other radiator vents are hissing, you may think that the system pressure is low, because you have the Pressuretrol set correctly but those Pressuretrols are notorious for being way out of calibration and you could be running at 2 or more pounds of pressure over your settings. Get yourself a 0 to 3 PSI gauge and add it to your boiler and see what is really happening. If the Pressuretrol needs to be recalibrated, we can provide you the procedure to do so.

nicholas bonham-carter

I agree-noisy ventsOften=overpressure.—NBC

mike85k

I got a 3psi gauge and installed it tonight. I plugged that pipe in the attic, and put a mom D on that radiator. I'll report back with results later. Thanks

mike85k

So I finally got the time to sit and watch the pressure gauge during a cycle today.
During a ~20 minute run the gauge barely moved at all, maybe bounced to 1/4psi but that's it. But runs like this I can hear air escaping/hissing from that upstairs radiator.

To test the pressure tool I shut off most of the radiators and fired it back up. It took a while to build pressure still, the pressure tool did not cut out until ~ 2 3/4 PSI, even though it's set to about one. So it is out of calibration.
Also, when it cut out it wouldn't come back on even after pressure dropped completely to zero, I had to fiddle with the pressure tool to get it to restart. Now I remembered that I have had this happen before as well. Is my pressure tool bad? I cleaned it at the beginning of this season.

Fred

It sounds like the pigtail (the looped pipe that the Pressuretrol is mounted on) is clogged. You may have cleaned it earlier this season but it still sounds clogged or the tiny orifice in the bottom of the Pressuretrol is clogged.
Did you ever post any pictures of the vents you have on each of the Mains? It also sounds like you don't have enough venting on the mains and all the air in those pipes have to be pushed out through the small radiator vents.

mike85k

I have two big mouths on my main, the pressure gauge is mounted on the pig tail too, so a clogged pig tail would block both no?
The riser for the noisy radiators isn't really off the main though, it comes right off from the header.

EBEBRATT-Ed

Lower the pressure. Also any pipe in an unheated space 9and I assume the attic is cold) will make an excessive amount of condensate that may get pushed into the vent especially if the pitch is questionable

Dan_NJ

mike85k said:

So I finally got the time to sit and watch the pressure gauge during a cycle today.
...
To test the pressure tool I shut off most of the radiators and fired it back up. It took a while to build pressure still, the pressure tool did not cut out until ~ 2 3/4 PSI, even though it's set to about one. So it is out of calibration.

Also, when it cut out it wouldn't come back on even after pressure dropped completely to zero, I had to fiddle with the pressure tool to get it to restart. Now I remembered that I have had this happen before as well. Is my pressure tool bad? I cleaned it at the beginning of this season.

I actually assembled a version of Gordo's rig to test my Honeywell PA404A pressuretrol and the best I can get it to do is cut out at about 2 psi and cut in again at about .25 psi. If I set it low enough to cut out at 1.5 psi it never cuts in like you're describing. I can live with 2 psi cut out if that's what it takes and eventually I'll get it working better.

Check out Gordo's setup here, worth 2 minutes of your time:
https://www.youtube.com/watch?v=mE1-QuUx4_c

Fred

Yes, a clogged pigtail would affect both the Pressuretrol and the gauge, but that doesn't mean a partially clogged pigtail wouldn't restrict the true reading on the gauge, or that a clogged orifice into the Pressuretrol wouldn't still be a problem.
Also, a riser/radiator run out directly off of the header, instead of off of the Main is probably the cause of the noisy radiator vent. All the air from the header to that radiator still has to be pushed out through the radiator vent and can not take advantage of those Big Mouths.

ethicalpaul

Your Pressuretrol is set for about a 2psi cut in plus whatever the differential dial is set inside (likely 1psi) so a cutout at 2-3/4 looks reasonably accurate.

Set the cut-In (the front setting) lower, like .5 and see if that helps. But don't keep adjusting it after the indicator hits the bottom at the .5 psi mark.

I can't explain why the fire didn't return until the pressure was down to near zero, especially with your relatively high 2psi cut-in. Mine has to wait for the auto-damper motor to do its thing and that makes it not kick in until about .25 psi so maybe yours is even slower?

Edit: also, what's that silver colored fitting under the pressuretrol?

Edit edit: do you have some kind of press-fitting on your steam supply pipe?

Dan_NJ

Even though my PA404A has cut in around .5 and differential set to 1.0 it still cuts out around 2.0 psi and cuts in around .25 psi. If I try to get the cut out lower the micro switch does not cut back in at all. Basically the lowest diff setting on my microswitch is not 1 like it says but really closer to 2. It's totally in accurate right out of the box.

BobC

The only thing they care about is it cuts out at 15PSI, anything else is irrelevant to them. Why waste money on anything when you can just put it in your pocket?

Bob

mike85k

Interesting, so it sounds like mine is behaving "normally" as others have experience this as well. When it wont kick back on I raise it the tiniest bit I can until it re-fires.
I'll disassemble everything and clean it this weekend.

As far as the heat upstairs, that radiator on the same riser as the attic pipe is heating just fine, and still relatively quiet, so I'm happy with that. In fact it seems more heat is being pumped into the rest of the system without that pipe, so it seems like an overall improvement keeping that plugged.

mike85k

Ethicalpaul, yes the boiler piping is done with press fitting, yes I know that is frowned upon here, I haven't not had any issues with that.
The silver fitting below the pressure tool is a filter thing, I forget what it's called, I was given this with the intent of keeping junk out of the pressure tool, is this ok?

JUGHNE

That may be a “snubber”, protects things from pressure surges.
Could be affecting your control.

You should not need it if you have a clean pigtail.
You might try without it.

Fred

mike85k said:

Ethicalpaul, yes the boiler piping is done with press fitting, yes I know that is frowned upon here, I haven't not had any issues with that.

The silver fitting below the pressure tool is a filter thing, I forget what it's called, I was given this with the intent of keeping junk out of the pressure tool, is this ok?

That fitting under the Pressuretrol is a "Snubber"
The Pressuretrol can be re-calibrated but you are only a few ounces off so not bad. Also, I think somewhere in this string you mentioned that the loud radiator is tied directly into the boiler header instead of off of the main. If that's the case, you can quiet that vent down by moving it to the main. Steam velocity and air in that run are problems for small radiator vents.

ethicalpaul

I wasn’t frowning about your press fitting, I was just curious—I’ve never seen one in use but have read about them, thanks!

That snubber thing makes me frown, though—I’d be concerned it was messing with my pee-troll, and those things are messed up enough as-is!

Fred

ethicalpaul said:

I wasn’t frowning about your press fitting, I was just curious—I’ve never seen one in use but have read about them, thanks!



That snubber thing makes me frown, though—I’d be concerned it was messing with my pee-troll, and those things are messed up enough as-is!

Snubbers are a good thing @ethicalpaul . They help prevent clogging of the Pressuretrol Orifice and also help minimize vibrations that affect mercury switches, not so much on micro switches.

ethicalpaul

Thanks @Fred !

mike85k

I cleaned everything up again, and removed the snubber. I could see it creating a pressure differential at pressures this low, I tried to blow through it and have a hard time getting enough pressure to flow through the filter, so I wonder if that was causing the pressure to either not get through to the pressure tool, or not depressurize quickly enough.
So far so good, but I haven't seen a short cycle, some cold temps coming up though so we'll see.

I still get a lot of noise out of the other two radiators upstairs while they are filling, and since its not a pressure issue I'm not sure where to go next. For the one in my bedroom, there are two vents, one I added to the riser pipe right before the valve with a maid-o-mist on it, with no orifice fitting, and a Hoffman 40 on the actual radiator. It is angled slightly towards the valve. The other radiator on the riser is also angled correctly and has a Gorton 5 I believe.

Thanks everyone for the input.

mike85k

So taking out the snubber seemed to help with the pressure, with that out and a bit of tuning I am able to get it to kick off at ~1.5PSI and kick back in at about .25PSI, so thats good. Some are still noisy, especially as much as its been running the past few days, but tolerable. I changed out that Hoffman 40 for a new vent-rite 1, and that seems to help, thats my first one of those and its a nice vent.

On a separate issue, I have always had some water leakage in my porch around my chimney, I always assumed it was getting in through the roof, and this summer paid good money to have my roof totally redone, and the chimney rebuild/re-pointed, and now its still leaking, maybe even worse. The roofing guys are telling me that its not the roof leaking, and that its an issue with my HVAC, and they want to send someone out to look at it. Is it possible the boiler is sending enough moisture out to come out of the chimney and cause something like this? I'm not loosing that much water, I would think it would take a lot going up the exhaust to do this.

JUGHNE

Could be condensation from the flue gases.
Looks like it has 3 cold sides.
Does it have a liner of any sort?

Does it dry up in the summer without rain?

Gsmith

might be the masonry seal around the top of the chimney where it seals the outer brick to the inner flue is cracked, rain seeps in and runs down. Easy to check by climbing up and looking.

mike85k

I don't believe there's any liner, the top was re-pointed, re-capped, and the top 6 feet were re-mortared so I wouldn't think water is getting in.
I asked these guys specifically if it needed a liner, and they said no, going to be quite frustrated if they come back and say it does not.

JUGHNE

It could have been sized for coal burning? Stay hot all winter long.
Could be too big and certainly too cold.

Fred

Is there a radiator in the room, above, at that corner? I had a similar situation a few years ago and I finally found a union coupling connecting the radiator and supply valve (straight valve out of the wall) was leaking and the condensation dripped onto the area above the porch and froze.

mike85k

My guess is that it was originally coal burning, the house was built in the 20's. There's no room above, this is in a porch/sunroom area with a flat-ish roof overhead.