General rules for air vent size?

Craig Curtis

ok I'm doing the big experiment tonight to see if I did the calculations right. If you go by what the descriptions on :
http://www.statesupply.com/displayCategory.do?Id=1816
has for the Gortons, They don't mesh with what I figured out. I am wondering if I did it right.
top floor with all of the big radiators, have size "D". Main floor, big radiators have size "C" (including the one in the same room as the thermostat). The small one in the kitchen, and the upstairs bathroom (very small radiator near main line) both got a "6." Maybe this will help with some of the hammering we've had over the last few years as well.

If this doesn't work, I'll try to get a TRV at least in the baby's room, so she doesn't cook...

Craig Curtis

General Rules for Radiator Air Vents?

I have a single pipe system, and the house was built in 1929. All of the radiators are working, but over the years as the air vents have been replaced, I don't think they are the correct size any more. so I was wondering if there are any general rules for selecting air vent sizes?

I ask this, because while they are ll working, the main floor has the larger radiators, and that is also where the Thermostat is located. The problem is, we have the thermo set at 65, but on the second floor, the bedrooms all get to about 75 or even 80, which is entirely too hot (by the time it cools to the thermostat temp, the radiator starts again to warm the first floor).

There are 3 radiators on the first floor, all of which have 11-12 "blades." The second floor has 3 radiators, all of which have a 13 or 14 blades per radiator. The first floor is a mostly "open" floor-plan, and the second floor has 3 bedrooms.

Is it a venting size problem, or is it something else?

Lurker_2

Vents

The vents control how fast the radiators get hot, but can't control their ultimate heat output.

If all of the radiators are heating all of the way across, or rather, at the same rate (which is the appropriate way for things to work), then you'll need to look elsewhere to fix your problem.

Fortunately, elsewhere isn't that far away. You can, for example, get TRVs for the upper floor radiators. These interpose themselves between the radiator and the air vent and will shut off flow to the vents once a certain temperature is reached. The effect of this is that it stops the radiator from receiving steam prematurely so as to avoid overheating.

-Michael

Craig Curtis

thanks for the idea. I'll go pick a few up today and see if that solves the problem. I didn't even know there was such a thing. I'll post back with my results.

Thanks again

Bob W._3

I agree that TRV's would be the way to go, but they cost a fair bit more than vents. What kind of vents do you have on the 1st and 2nd floor rads? Experiment a little. Put adjustable Hoffman 1A's on the 2nd floor rads and try the lower settings.

Craig Curtis

It seems I've found some honeywell TRV valves online for about $12. Are those not the correct ones? There are others for over $100, so I don't know what the difference is. The valves that are on there now are mixed between an adjustable honeywell, and a self-adjusting kind with a fixed hole size (like size "C", EDIT: MAID-O-MIST from Home Depot)

I was just going to run to Home-Cheapo, but would they not have the correct valve?

DanHolohan

Here

Balancing Steam.

Everyone wins.

Bob W._3

Craig, there are TRV's specifically made for single pipe steam. They are sold in 3 pieces, the valve, the control, and the vent. They generally want to sell you a Hoffman No. 41 vent, which is the straight shank cousin to the Hoffman No. 40. My take is that you have to put a faster vent on there, like an adjustable Hoffman 1B. You have to buy all three to make one unit for one radiator. Made by Danfoss, Taco, Macon and Honeywell-Braukmann, I believe. Where did you find some online?

Bob W._3

Definitely recommended.

mel rowe

FWIW, I've bought quite a few TRV's. They happened to be the only one I knew of at the time. There were 3 parts involved--- a valve body, an air vent, and a thermostatic control. I bought Honeywell Y100P-1001, which includes the first two parts, plus T100A-1028. I think you can find these three for a total of about $63, which is a lot more than the normal rad. valves, but in some cases well worth it.

Craig Curtis

after closer inspection, I had only found the actual thermostat part, and they were all in the UK, which doesn't do much good to me here in Jersey. Don't think I want to wait while I fry in my bedroom, and freeze in the livingroom... I'll try Home Depot and the local plumbing supply...

Craig Curtis

ok. I bought it. I assume I'll get it in the email...

so how long does it take to get the file? I was hoping to get what I needed today.

Bob W._3

That web site is simply repeating what is on Gorton's site. They use the old method of figuring by distance and orientation (NSEW). I find that a combination of this method and Dan's method (size of radiator) works well. IOW, just experiment until you get the right combination. Maybe use some 1A's where the rooms are already warm; just dial them down. Good luck.