Main venting check/options

Matt_28

Thanks for your feedback.

Fred, I am cutting out on pressure during the first morning cycle out of setback. Pressure cuts out just before 2psi with and L404. I will try your paper idea to see when the vents close. I think they are working well since I do hear them open and close during the cycle.

Steamhead, I had planned to upgrade my 2 ventrites to 2 gortons. Do you know how much pipe a ventrite 35 will vent? Just curious for the comparison


Michael, I currently have ventrite adjustable radiator vents. The ones that are open completely are the loudest. I figure if I had larger vents they would be even louder. Will large Gorton radiator vents hiss just as loud as what I have? If I slow the rate I figured it would result in slower heating.

Just to give more information. I keep my upstair adjustable vents at about 3 out of 10. They heat the upstairs well during the first morning cycle. The upstairs stays warm all day even though those radiators barely get steam during the rest of the day. It is the downstairs radiators that get the loudest which have the 2" risers.

Can anyone give me suggestions on new radiator vent options to alleviate the hissing and what I should expect with these vents based from my measurements in the original diagram?

Thanks
Matt

Matt_28

main vent size check/options

I currently have what I think is adequate venting on my 1-pipe system, but I still have slow radiator heating and loud hissing radiators.


Maybe, I did not measure correctly when I posted sizes in the past. Please see diagram below for my full system measurements. What I think are my mains measure 26 and 32 feet of 2 inch pipe. If I add the additional 2 inch radiator take-offs they become 61 and 39 feet not including the 1.5 inch risers and 1.25 inch dry return. These new numbers with take-offs seem to be much larger in comparison so I think I probably need more venting. I currently have 2 Gordon #1's on the 26 foot section and 2 vent rite #35's on the 32 foot section. I have switched the vents around a bit without good results.

Please advise if this should be adequate or maybe it is my vent location. They are located at the end of the return directly above the elbow leading back to the boiler.

Fred Harwood

Venting

Slow heating and loud hissing are a strong indication that your mains are not vented well enough, or that the vents are not reopening soon enough. I would start with two Gorton #1s on the 32-foot line, then ensure that all the Gortons reopen for each cycle (they won't if they cannot cool below about 140F each time). You can rig a strip of paper close to the vent to get a visual indication of its open or closed state as it breathes. Also, are you cycling on pressure before all the rads get hot?

Steamhead

Try using

two Gorton #1 vents on each main. The 2-inch radiator takeoffs are vented by the vents on the radiators.

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michael_15

takeoffs don't count

Since the main vents don't vent the air in the takeoff pipes, don't count them when sizing the main vents. Given that some of your takeoffs are so large (2nd story, I imagine) that they almost rival the size of the mains, you might want to look at the size of the air vents on the radiators themselves.

Those are just my non-professional thoughts as a fellow homeowner.

-Michael

Steamhead

You might check

to see if the boiler is oversized. If so, this can cause the vents to hiss.

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gerry gill

the ventrite 35 can vent

only .2 cubic feet per minute at 2 ounces..thats point 2..not much..

Matt_28

boiler sizing

I have been trying to figure out if my boiler is in fact oversized for my radiation. Can you help to confirm my numbers and proper method?

327 radiator sq feet x 240 btu = 78,480 x .33(piping factor?) = 25,898 + 78,480 = 104,378.

I am unsure if the piping factor is correct, plus I do have insulated pipes.

I have a Burham IN5 boiler with ratings attached.

michael_15

looks good

to me, though I'd look for a second opinion. One thing to consider if if you had radiators removed -- this would generally mean that your pipes are a lot bigger than 327 sq.feet of radiators otherwise need, which would result in you needing to use a bigger piping factor. If you otherwise have an unusually large amount of pipes (a professional could probably tell by looking at your system), that might increase your piping factor as well, which would result in your boiler actually being somewhat undersized. For example, in my home, every radiator takeoff is at least 20 feet, some being 30-40 feet (longer than the steam main) (absurd as it sounds), so I use a bigger pickup factor.

To some extent, the piping factor is not to take into account the heat loss out of the pipes, but rather the load it takes to heat up the pipes. Insulation matters, then, but it doesn't remove the obligation to include the piping factor.

-Michael

Matt_28

boiler sizing

Can anyone explain to me the Burnham rating above? Do I compare my 104,378 to the AGA Input of 140, Heating capacity of 115, or the Steam MBH of 86? Possibly another measurement of Steam SQ Feet of 358 to my 327 with or without a piping factor?

Michael, Thanks for your input. This boiler was installed in 2003 and I have not had any radiators removed since. I also don't have any extra piping leading to unknown areas.

Thanks
Matt

michael_15

List of values on the rating sheet

For a steam system, this is how I look at them:

DOE: The actual heat energy that doesn't go up the chimney.

All of the other values I usually ignore. They're useful for things like efficiency and what not, but let's ignore those.

You have a DOE of 115,000. What the ratings sheet does for you, in case you don't like to do math, is apply a 1.33 pickup factor to convert the 115,000 into a "net" amount of radiator radiation: 115,000/1.33 = 86,000 (or so). This is the IBR Steam MBH value.

Then, if you again don't like to do math, it'll use the 240 BTU/sqft radiation conversion to convert that 86,000: 86,000/240 = 358 (or so). This is the sq.ft rating.

Thus, if you for some reason didn't like to divide by 1.33 or 240 but did have the wherewithal to figure out the total radiation on your radiators, you could just look at the steam sq.ft. amount. Assuming, of course, that the 1.33 pickup factor is appropriate for you.

-Michael

Unknown

Easy way

Read the sq ft steam column. That's what it will heat with a 1.33 pick-up factor.

If your mains are insulated, use that number.

More vents, and all open wide spreads the load around more, gives gentler venting; FAST venting.

Slowing them down makes them jet. It's the same amount of air squeezed through less hole.

Kindasorta like putting your finger over the end of the garden hose. It don't slow the venting at the "finger", it speeds it up. It isn't quieter, it's louder.

Open those puppies up. Add to them. Vent the risers. Put two vents on the fat slow radiators. Don't hold back on the air.

Your mains are insulated, aren't they? I forget......

Noel

Matt_28

thanks

Thanks Michael and Noel, I understand now and at least I can feel comfortable that my system is not oversized.

Okay, back to venting. I guess I need to open up all the vents or add more, plus get back to ordering my other Gorton main vents. I hate to open the upstairs vents all the way since that will cause the upstairs to overheat.

My one largest radiator is a 5 tube with 70 of the 327 sq feet, I should probably start their. Please see picture below. I think I should drill and tap at spot A to add another vent. Spot B may look a bit odd, but for some reason their is already a tap there.

t. tekushan

spot a

Spot a is better.

Spot b is used for an air bleed valve if the radiators are used for hot water.

Steamhead

Or

use a Gorton #C or #D vent on that radiator.

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Matt_28

vents

Thanks for your advice.

I have had good luck with the Gorton Main vents. How are they for radiators? Specifically, will the C or D hiss loudly and clank shut, like my ventrite does now?
Matt

Steamhead

Gortons are fairly quiet

but like all vents, they do hiss sometimes.

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