Upstairs radiator only heating part way

Klaas

After learning lots and making some tweaks, my one-pipe steam system is doing pretty well--mostly quiet and pretty well balanced.  However, I have one 2nd floor radiator that doesn't heat up well.  It's 4 sections, and it seems like only the first is ever really hot, the second gets warm, and the other two stay pretty cold.



I took it off to see if there was junk inside, but it looked surprisingly clean in there.  The valve also looked fine.  The two weird things I've observed are:

1) sometimes it makes a bubbling sound--not from the vent, but I can't tell if it's from the radiator or the riser, and

2) I took the vent off when the boiler was firing once, and the steam didn't take the opportunity to escape.  In fact I held a tissue in front of the hole and it was breathing in and out a little.



Both of those made me think there was water pooling in the bottom of the radiator and blocking steam from getting through, but that doesn't seem to be the case.  Are there other possibilities to investigate?  The riser goes up through the wall, so I can't see exactly what it's doing, but the part in the basement seems unproblematic--takes off at an angle and pitches up to where it connects to the vertical pipe.



Any suggestions for things to try?  It's a pretty inconvenient radiator to have not working, since it's in the babies room so we end up running a space heater to compensate...

nicholas bonham-carter

Baby's room cold

Have you tried raising up the vent end? Use quarters under the feet, and while you are at it, raise up all four feet, raising the vent end one quarter higher(check with a level for pitch). The floor may have sagged in that spot, and there may be a horizontal section in between the takeoff at the main below, and the exit from the floor above. If that has been the case, the horizontal will have pitched the wrong way, and raising it may correct this.--NBC

moneypitfeeder

if the open vent didn't do it

Then I would think you have a sag in the pitch of the riser going to that rad. The breathing in and out suggests the water hammer effect that is trying to happen to overcome the incorrect pitch, but with a 1 pipe the pipe diameter is maybe large enough to hold all that pooled water without making horrendous banging noise. In my system (2 pipe), we had a rad that did the same thing, only it wouldn't even heat the first section. with the trap end open you could get gurgling, breathing and eventually a little more heat, but with the supply end and a towel poised to cover it, and a wrench ready to tighten it back up, if that end was opened the venting allowed the steam to overcome the water and reach the rad. But the next cycle it still wouldn't heat till the runout from the riser was pitched correctly. Good luck

Klaas

Second round pending...

Thanks for the advice.  Unfortunately no improvement from the first little adjustment.  I've propped it up a little more and will see what happens next time (didn't need much heat today, so I didn't get a second trial). 



Thinking more about how the pipe would have to be routed in the wall, it does make sense that there would be a horizontal run of a few feet in one direction and possibly a foot or two perpendicular to that.

STEAM DOCTOR

location

Where is this radiator in regards to the main( beginning,middle,end)?

Dave in QCA

It's puzzling

The fact that you can hear a bubbling sound is telling.  You indicate that riser goes up through a wall.  Does the supply then go to the floor and then up, or does it come out of the wall.  The bubbling sounds like there is a small pocket of water in the piping, while this will usually result in water hammer, it sometimes is quiet like you describe.

On another front, what vents are you usuing on the radiators?  If adjustable type, what settings, etc.   There is a slim chance that this is a balance problem, but not likely.

Scot B

Chapter Seven: one pipe steam- a matter of detail

If you have the Lost art of steam heating read that chapter. Check your main size, run out size, riser size, connected edr load and lastly check your radiator valve size.

If you don't have it, buy it, it is a world of information!

Good Luck!

Klaas

Second round: maybe a little better?

Thanks again, everyone.  The third section was somewhat hot by the end of the latest heating cycle, so I think that's an improvement.  The fourth was still cold, though.  I didn't hear any bubbling this time, but I was only in the room to check on it a few times, so there could have been some that I missed.



Location: It's a single main with the boiler at the front of the house.  This is the 5th riser out of 7.  The 7th (rear upstairs bedroom) does fine (the 6th does so-so, but I blame that on the riser being a seemingly recent replacement by someone who didn't know their stuff and undersized the pipe).



Routing: The riser connects to the main just inside the garage (which is below the kitchen).  There is a maybe 6- or 8-inch section at about a 45 degree angle then that connects to the vertical pipe.  That's all I can see from below.  In the bedroom, it comes out of the floor.  The corner of the bedroom is about 4 feet over and 1 or 2 feet forward of where the pipe goes up from the garage.  I assume it goes up first then travels through the floor/ceiling between the floors.



Vents: They're all Hoffman 40 except the front bedroom where I have an adjustable (I think Maid o' Mist) kept almost closed because the room is little used but was heating up a lot.  Should I try a fast vent (or no vent) again?



I will check out Lost Art chapter 7 (I do have it. A great read).  I can say, though, that the piping and valve sizes are the same for this radiator as for the bathroom and rear bedroom ones that do fine.  The bathroom radiator is the same but with 3 sections rather than 4.  The bedroom one is about twice the size.

rcrit

always have a vent

A vent should always be installed. Steam is dangerous stuff both for causing burns if you happen to stick your hand in it or driving out all the oxygen of the room if left on long enough.



I'd try a variable vent like a Hoffman 1A. It has a bigger venting capacity than a Vent Rite #1 (atherwise an excellent vent). The mother of all fast vents is the Heat Timer Varivalve. Even at "off" it vents like crazy. This vent is looked down upon by most of the wallies but I had decent luck with it with my last boiler. Even with this vent my rads never filled all the way across though. One of the criticisms is that it doesn't close when water hits it.

Klaas

Just for experimenting

Yeah, I threw that parenthetical in without clarifying, but I mean just removing the vent briefly as an experiment.  When I tried that a while ago the radiator breathed in and out a bit but no steam came out.  If I tried it again, I would be watching it, gloved, and ready to shut the boiler off if steam actually got to the vent hole.  Basically I don't want to buy a new vent if even an open vent hole doesn't get steam into the radiator.

Klaas

Third round: definite improvement

I took out the stacked quarters and put in some little pieces of wood trim to get it even higher (about 3/8"), and it's definitely doing better.  At the end of this morning's cycle the 4th section was hot!  So I call this problem solved.  I'm going to get a faster vent, though, since the more heat I can get into that room the better.