DIY Vent Work?

grichane

Hi there,

I am entering my first winter in my new home purchased this summer. Has a one-pipe system (1910) which probably needs some tweaks, but I'm just sleuthing it now as the weather cools off. I'm hoping to tackle easy stuff first, and frankly do as little intervention as possible this winter. I have limited time, and can't screw things up majorly as I have a new baby who needs heat. I need to avoid paying a pro for stuff right now barring emergency (which I don't have as of now).

Have had boiler checked by reputable company and been advised that it's good to go safety-wise. They advise that despite it's age (sometime before 1959 per a resource i discovered here) it should go for a while. It has some modern parts (low water cutoff, pressuretrol, new sight glass assembly and main vents*). Runs on gas. Some assorted questions to start I hope folks can weigh in on:

1) Can I replace radiator vents myself? Are there a lot of ways to screw it up or do i just unscrew and put the new one in? Again: I can't afford to lose heat altogether - even for a day. I definitely want to avoid screwing something up majorly, then having to pay someone on short notice. I suspect short notice will cost a lot and get me shoddy work at this point in the season.

2) If mains are already tapped, can i put in new main vents? And is there any reason not to go as big as possible? Seems like folks here think bigger always better?

Background:

Radiators: There are two types of radiators, one the taller silver type with tie-rods on fl 2 (what I've always lived with in apartments in NYC, Boston and elsewhere), and a lower profile boxier type (fl 1). Plus what I'm told is a European hot water rad tweaked to steam). That's pretty new- less than 20 years, maybe 10.

Rads have 4-5 different vent-types - some vintage i think, some modern nice, some modern crap (one just says "Taiwan".) I suspect none of them are good on fl 2 - it's not getting warm up there as fast as fl 1. I think building envelope is part of the issue because actually fl 2 cools faster. Other issue is that the first floor seems to be getting upward heat from the basement/boiler room and a long run.

In any case, to balance the house I likely need more heat upstairs and a little less downstairs. Hoping I can do this with rad vents... or at least get close to start before i start messing around with lifting rads, insulating hidden pipes etc.

I saw another post suggest maid-o-the mist for folks playing with balance- does those make sense?

Mains: There are two modern main vents (ventrite 35s). Previous owner overfilled boiler (presumably thanks to inoperable sightglass, now fixed) , so they are covered with water stains from overflow (right?). Could they be gunked up and screwing things up? Can I take them off and try to clean/replace or does a pro need to do that?

Thanks,

Greg

nicholas bonham-carter

First have a look at the main vent(s). Just because you see them in place does not mean they either work or are adequate for the job. Radiator vents will usually last much longer, as they are only designed to allow the small amount of air in the riser, and radiator to escape, as steam begins to rise from the boiler.
Post some pictures of those main vents, and the supply piping around the boiler, and we can advise what your next step should be. Also, pictures of the boiler, and it’s controls will help.
Spending a couple of Franklins on the mains is much more cost effective than on the radiators, assuming they all work.—NBC

BobC

VentRite 35's vent at about 0.11 CFM and are considered to small these days (Gorton #1 is 0.33CFM -Gorton #2 is 1.1CFM and the Big Mouth is almost twice as much as the G#2), the key is to vent mains fast and radiators slowly. Tell us how long each main is and what size pipe and we can recommend what vents would work for you. Note that a 2" pipe is 2.38" OD and a 2-1/2" is 2.88 OD, the length does not have to be exact.

If the two steam mains are of different lengths you will need vents that are proportionately sized so steam arrives at the radiator feeder pipes at about the same time.

Once the mains are sorted out you can turn your attention to the radiators. In the meantime make sure all the radiators have a little slope back towards the input valve so water can drain out. Also put a level on any horizontal pipe you can reach in the basement and make sure they have some slope so water can find it's way back to the boiler. A vent will unscrew from a radiator but don't use excessive force or one might snap off, use teflon tape on a vent threads before installing it.

Bob

grichane

Thanks for your thoughts @nicholas bonham-carter and @BobC .

See shots of main vents, supply piping and boiler controls.

I think they are two-inch pipes. Unfortunately the basement is partially finished so measuring length is going to be hard for now as much of them are boxed in. Don't know if whats's boxed in are mains or runs though. What I can see has slope.

As to rad valves: a couple didn't really release any air at all (rads stayed cold) and i fiddled a bit and got spiting steam (they have a little screw on top, otherwise no real way to adjust.)

Another question: what differentiates between a main and a run? I can see some pipes within the finished box... those are un-insulated:(

Jamie Hall

There really isn't much difference between a main and a run -- I usually think of mains as having two or more radiators branched off them, and runs as serving just one. But a long almost horizontal run -- say 15 feet or so -- could be thought of as a main. Would you need to separately vent that long run? Probably not, but the vent on the radiator might need to be a tad bigger to get that radiator to heat evenly.

As noted -- step one is to get the main venting adequate. It's hard to over vent a system, except in terms of the cost of the vents themselves. It's easy to under vent -- and those Hoffmans, even if they are working, almost certainly aren't big enough.

Once you get the mains vented, then you can start playing with the radiators. This can take time, as changing one radiator will affect others. Also, it's usually better to try to slow down a fast radiator than to try to speed up a slow one. The Maid O Mist adjustables are quite handy.

grichane

Thanks @Jamie Hall . Those are actually ventrite 35s.

Can I do mains myself assuming I’m just replacing in the same spot?

Jamie Hall

Yes -- just be a little careful unscrewing the old ones. They're a little balky sometimes...

1Matthias

Jamie Hall said:

Yes -- just be a little careful unscrewing the old ones. They're a little balky sometimes...

I've discovered this the hard way...a 10 minute easy little job turned into 3 hours of swearing...

grichane

Hi,

I’m still poking around and understanding the system before taking action. Upon further examination: I’ve realized that the vents are actually on dry returns. However, not all radiators are on a dry return- some just have a main + a run and use those pipes to get back to the boiler. This includes at least one which is closet to boiler, driving heat in warmest room which of course is where thermostat is. I’ve dialed rad vent back on the that one all the way, but it still heats. Notably, this radiator is a different vintage than others in the house. A late addition perhaps?

Anyway, are mixed systems like this normal? Should this change my thinking at all?

Thanks,

Greg

BobC

What kind of vent did you dial back? If it's a big box USAV vent the dial really dos nothing, they vent at the same rate no matter where you set them. If it's a Hoffman 1A you have to be careful the rotating cap is centered or the settings are not correct. THe VentRite 1A is the only adjustable vent that really works, the Maid O Mist 5L that has replaceable orifices also works - it's just to simple not to work.

Bob