vapor stat turns off the 2nd floor radiator before its fully hot. TAP a 2nd HOLE???

tumbz

so i installed a new vapor stat and balanced my 1 pipe steam system.

before i had alot of banging and after installing the vapor stat and setting it to 8on and 14 off, leveling my radiators better, and playing with the first floor rad air vents, the system no longer bangs and heats quickly and evenly on about 2-4ounces of pressure. I have 2 x big mouth air vents on my mains and i use vent rites #1's on all my first floor rads..

so i have 2 rads upstairs that gets steam last. they get hot , but not blazing hot like they are supposed to.... I HAVE 2 x MAID O MIST "Ds" on both of them. These should be the fasting venting air vents.

my vapor stat runs fine at about 2-4 ounces and quickly heats up the whole first floor, but as soon as the heat goes upstairs, the pressure builds up to almost 1 pound, and shuts the boiler off before the thermostat can..... Both the upstairs radiators gets hot, but not as hot as they should be.....

Im thinking the issue here is the MOM D's air vents, even though as fast vents, arent venting these 2 BIG upstairs radiators fast enough.

SHould i tap and add a new air vent hole on the other side of the radiator to double the air venting ??????

is this the right drill bit and tap to buy ???? (( 1/8-27 NPT Tap and 21/64" Drill ))??


Heres a picture of my upstairs radiator. If you see where the air vent is now, there is a raised area exactly on the other side where im thinking of tapping a 2nd air vent hole.

Jamie Hall

Were these radiators heating OK before you changed to the vapourstat?

Before you start drilling holes in the radiators, several things first. Make sure the runout and riser feeding them is large enough to handle them. if it is, make sure that it has adequate pitch; you may be still having condensate lying in there, even if it doesn't bang. Then if the we're good so far, how long is this runout and riser? You might, if there is a moderately straightforward way to do it, consider putting a main vent on the riser as close to the radiators as possible.

tumbz

My home is finished , so i cant see any piping.  I was thinking adding this 2nd hole on the radiator is kind of like adding a vent on the main...    i jave no idea how any of the piping looks since this home was renovated before i moved in.

KC_Jones

IF 2 D vents per radiator isn't getting it done, then more venting isn't going to help. Best option I see is to slow down the first floor rads.

I agree with Jamie on the water laying. You have banging, so you have water laying around somewhere and these slow second floor rads could be another sign of that.

Slow down the first floor and see what that gets you.

On an anecdotal note, I vent rads even larger than yours, quite effectively, with a single #6 vent.

tumbz

KC_Jones said:

IF 2 D vents per radiator isn't getting it done, then more venting isn't going to help. Best option I see is to slow down the first floor rads.

I agree with Jamie on the water laying. You have banging, so you have water laying around somewhere and these slow second floor rads could be another sign of that.

Slow down the first floor and see what that gets you.

On an anecdotal note, I vent rads even larger than yours, quite effectively, with a single #6 vent.

its strange that if i slow the first floor rads anymore, for example, i can close the air vent on another rad in a room thats not used, i will hear banging again.

right now, the way i set all the air vents, theres no banging. I guess i have to play with the system even more.

you guys talked me out of it. i almost bought the drill and tap from amazon. ill play with it some more.

tumbz

KC_Jones said:

IF 2 D vents per radiator isn't getting it done, then more venting isn't going to help. Best option I see is to slow down the first floor rads.

I agree with Jamie on the water laying. You have banging, so you have water laying around somewhere and these slow second floor rads could be another sign of that.

Slow down the first floor and see what that gets you.

On an anecdotal note, I vent rads even larger than yours, quite effectively, with a single #6 vent.

i reread what you said and just to clarify, i only have 1 x MOM D vent per radiator upstairs... NOT 2 Ds... Do you think 2 Ds would help? i was thinking about TAPPING another hole to vent faster.

Jamie Hall

tumbz said:

My home is finished , so i cant see any piping.  I was thinking adding this 2nd hole on the radiator is kind of like adding a vent on the main...    i jave no idea how any of the piping looks since this home was renovated before i moved in.

Not really. A vent on the riser -- you might even be able to get it located right at the inlet -- vents the riser and runout, but does not affect your control of the radiator. A vent on the radiator itself affects the control of the radiator. It may look the almost the same, but it isn't.

ethicalpaul

First, what @KC_Jones said I completely agree with. Do not increase the venting on your radiator, it won't help.

What is the EDR of your radiation and what is the net sq feet of steam rating of your boiler? I want to know if your boiler is wildly oversized (which it seems it must be if still builds pressure with a D vent on your radiator or see "water trap" possibility below)

When you see the rising pressure, I assume your first floor radiators' vents have started to close due to steam reaching them?

its strange that if i slow the first floor rads anymore, for example, i can close the air vent on another rad in a room thats not used, i will hear banging again.

Banging is 100% due to water being where it shouldn't be. As was earlier mentioned, you may very well have a "water trap" in the supply piping to this radiator. This would also explain why that radiator is slow to heat. Here is one scenario:

- you have a "water trap" caused by a sag in the supply to that radiator. Condensation collects in this area.
- This water trap will provide a resistance (high pressure zone) to any steam/air flow to that radiator, keeping it cold
- When your other paths for the steam to go are eliminated (like your downstairs radiators' vents start to close due to steam), then the "water trap" can no longer hold back the flow of air (pushed by steam)
- As the air flows (and vents out of your D vent), the steam follows and hits the water in the water trap, causing banging.

I had this very situation when I was far more ignorant and with the help of this forum I was able to solve it. See https://forum.heatinghelp.com/discussion/167233/fixing-pitch-issues-in-old-house

tumbz

ethicalpaul said:

First, what @KC_Jones said I completely agree with. Do not increase the venting on your radiator, it won't help.

What is the EDR of your radiation and what is the net sq feet of steam rating of your boiler? I want to know if your boiler is wildly oversized (which it seems it must be if still builds pressure with a D vent on your radiator or see "water trap" possibility below)

When you see the rising pressure, I assume your first floor radiators' vents have started to close due to steam reaching them?

its strange that if i slow the first floor rads anymore, for example, i can close the air vent on another rad in a room thats not used, i will hear banging again.

Banging is 100% due to water being where it shouldn't be. As was earlier mentioned, you may very well have a "water trap" in the supply piping to this radiator. This would also explain why that radiator is slow to heat. Here is one scenario:

- you have a "water trap" caused by a sag in the supply to that radiator. Condensation collects in this area.
- This water trap will provide a resistance (high pressure zone) to any steam/air flow to that radiator, keeping it cold
- When your other paths for the steam to go are eliminated (like your downstairs radiators' vents start to close due to steam), then the "water trap" can no longer hold back the flow of air (pushed by steam)
- As the air flows (and vents out of your D vent), the steam follows and hits the water in the water trap, causing banging.

I had this very situation when I was far more ignorant and with the help of this forum I was able to solve it. See https://forum.heatinghelp.com/discussion/167233/fixing-pitch-issues-in-old-house

Paul, i also love this forum and appreciate all of your input. You guys talked me out of adding the 2nd tap.

I cant answer the EDR and the net sq feet of my boiler because i have no idea and my home is finished from top to bottom so i cant see any piping at all. STUPID ME.

I will start playing with my air vents again to try to balance this better.

ethicalpaul

A finished home is typical at least on the above-ground floors

Be aware that balancing may not solve this...it sounds like you already tested balancing at the extreme end with the D vent on this radiator. If that radiator isn't getting hot with a D on it, then something else is happening (like a possible water trap).

You can find the EDR answer and I'd advise it, even solely for your own information unrelated to this issue. You get Steam Heating The Lost Art from the store available right on this site and it has charts that will let you "size" each of your radiators, then just add those values together.

tumbz

ethicalpaul said:

A finished home is typical at least on the above-ground floors

Be aware that balancing may not solve this...it sounds like you already tested balancing at the extreme end with the D vent on this radiator. If that radiator isn't getting hot with a D on it, then something else is happening (like a possible water trap).

You can find the EDR answer and I'd advise it, even solely for your own information unrelated to this issue. You get Steam Heating The Lost Art from the store available right on this site and it has charts that will let you "size" each of your radiators, then just add those values together.

the upstairs radiators gets hot. they get super hot as long as the vaporstat dont turn off the boiler when the pressure is reached. OR if the thermostat turns off the boiler because its been satisfied.

I lowered certain first floor radiators again. if i lower them too much, i get banging again. its weird to describe..... sounds like an easy solution to just slow all the first floor boilers, but a certain few radiators if i slow too much, i get crazy banging. when i open the air vents all the way, no more banging.....

so im on a thin line between banging, balancing my first floor to the sloweest setting without creating banging, and getting the upstairs radiators blazing hot...

tumbz

ethicalpaul said:

A finished home is typical at least on the above-ground floors
Be aware that balancing may not solve this...it sounds like you already tested balancing at the extreme end with the D vent on this radiator. If that radiator isn't getting hot with a D on it, then something else is happening (like a possible water trap).
You can find the EDR answer and I'd advise it, even solely for your own information unrelated to this issue. You get Steam Heating The Lost Art from the store available right on this site and it has charts that will let you "size" each of your radiators, then just add those values together.

GUYS, i foudnt his picture on the this forum. Someone who also could not get heat to the 2nd floor. Not exactly my problem, but i figure if i try this, it wont hurt. This is like adding an extra vent to the main or supply lines since i cant get to mine, since my home is all finished.


What do you think?

mattmia2

Does the banging happen only after the upstairs radiators get very hot when you slow down the 1st floor radiators? I'm thinking once they start producing normal amounts of condensate that is collecting somewhere and causing the water hammer.

The other possibility is that the t-stat is causing longer heat calls because the radiators near the t-stat are heating more slowly and the boiler is surging and has more time for that surging to throw water up in to the piping.

The boiler is still steaming when it has pressure, when the vaporstat turns it off, it is because it is producing steam from the heat in the mass of the boiler and it is being produced faster than the radiation can condense it.