Attic Radiator Sloshing/Spitting Water

Miringanes

Bought my house last year and I have a fairly large radiator in the attic on my one pipe steam system that I cannot for the life of me get working. 

The valve is full open and when the radiator heats up approximately 2/3 of the way it beings sloshing and if I let it fully heat up, it’ll start spitting water out the air vent. 

I’ve tried adding some pitch back to the valve but it still sloshes and spits. 

I’m not sure exactly where to go next with this. I’m thinking there’s a horizontal section of pipe that may not be pitched correctly below the floor so i may try shimming the valve side an 1/8th of an inch to see if that helps. 

Any thoughts? 

neilc

what kinda shape is the rad valve in ?
think about checking that the disc hasn't separated and is trapping condensate from returning,
also, if the vent is too fast, it cold be holding that condensate up the riser, and or in the rad,
pictures of each?

neilc

also,
what pressure are you running at?
as low as you can go is good, better, best,
pic of Ptrol,
and has the pigtail been serviced?

Jamie Hall

Your thinking about a horizontal pipe somewhere on the way to the radiator sounds like a pretty good guess to me. I'd be inclined to lift the whole radiator a good bit more than an eighth of an inch, though.

Miringanes

neilc said:

also, what pressure are you running at? as low as you can go is good, better, best, pic of Ptrol, and has the pigtail been serviced?

I’ll snap some photos in the am. The valve looks pretty new. Pressure is below 2psi and the boiler is a brand new EG45 installed by a member here with a pretty well respected outfit in the NY/NJ area so I’m certain the boiler is piped right and the pigtail should be good. Boiler has been skimmed and doesn’t surge.

I do think it’s this one specific radiator because the rest of my system runs as good as a 1927 steam system can, it’s quiet and heats evenly. I have a Gorton 4 on the problem radiator which is probably slow for an attic radiator. 

What baffles me is why the condensate begins sloshing around only when the radiator is more than 2/3 hot. My relative layman’s understanding is steam begins condensing as it hits a cool radiator so there’d be condensate that would get trapped as soon as the first few sections begin to heat up. 

BobC

That radiator or the horizontal pipe that may feed it is holding water, lifting the whole thing up a 1/2 or more. Just be very gentle you don't want to break anything.

Bob

ethicalpaul

What does the installer say?

Miringanes

ethicalpaul said:

What does the installer say?

Working on having him come out to take a look, since it was May when he put the boiler in, I had said let’s wait till fall to troubleshoot anything that might come up. I kinda dragged my feet reaching out because we don’t really use the attic much so it being cooler isn’t bothering us. Between heating emergencies and the holidays they’re understandably backed up. 

When he was calculating the EDR for the boiler in the spring he did note that it was a huge radiator for the location and it was in a slightly odd location (off to the side of the window). He thought the original may have been replaced at some point with the big boy when the attic was converted into living space. 

Miringanes

I’m reviving this from the dead, finally had some time to take a look at the radiator. I couldn’t get the valve side of the radiator lifted to try to possibly get some pitch on the horizontal run under the floor. It just won’t budge and I don’t want to force it as I know it’s definitely tied to the same riser as the radiator in the room below. 

What I did do is swap out the Gorton 4 for a Hoffman 1A that I have set all the way down a little past 1 in an attempt to really slow the venting. I have the system on now to see what happens. 

I’m adding some photos of the radiator and the piping. My plumbing and mechanical ignorance tells me that the radiator is too big for the piping and is generating a ton of condensate that eventually overwhelms the piping. (I am an architect but don’t deal with steam systems regularly except for my house) 

I say this because once 8 sections of this particular radiator heats up, that’s when the sloshing gets bad. All the other radiators in my house with the same size valve and piping are 8 sections. The piping on my larger first floor radiators is much bigger. Once again, I’m a little ignorant on this 

neilc

did you ever check that the disc was good and secure inside that rad valve?

Miringanes

neilc said:

did you ever check that the disc was good and secure inside that rad valve?

I didn’t, what’s the best way to do this? Disconnect the radiator at the union and look in? 

neilc

that or unscrew the top, use 2 wrenches and back up the valve, and don't rip that cap apart,
might be easier and safer to open the union

neilc

expect condensate at that union

Miringanes

neilc said:

expect condensate at that union

I mean could this also be part of the problem? There’s obviously a high point caused by the bushing that reduces the radiator inlet to the 1” valve. 

This particular riser is 1” all the way from the basement to the 3rd floor. Two radiators are on this riser, an 8 section on the second floor and a 16 section on the third (pictured). There’s obviously a condensation backup issue going on. 

neilc

not sure, I don't think so,
there's always some condensate sitting in the bellies of the ribs,
try a dead slow vent on this rad

ethicalpaul

The condensate isn't overwhelming, don't worry about that.

Miringanes

Ok so I’m holding off on pulling the radiator right now because it’s averaging 20 degrees outside and I don’t want to shut the boiler down right now, probably going to wait till it warms up next week. 

I have the spare Hoffman 1A on there set to 1 and it’s been through 3 heating cycles. Every time the radiator only heats 8 sections at most by the time the call for heat ends. There has been no spitting out the vent. I can hear a faint sound of liquid moving during the heating cycle which sounds like it’s beneath the floor but it’s nowhere near as bad as the sound the radiator was making with the Gorton 4 on there. 

I run my system on an ecobee and average 5 sensors across the house. I’m going to keep an eye on this because I do a 1 degree setback at night for comfort and switch the averaging to the bedroom sensors only (bedrooms are typically hotter) I have a feeling I’m going to have an issue with this attic radiator when the whole house gets averaged and there’s a need for makeup heat in the morning. 

EBEBRATT-Ed

You could take the valve off and put a tee in it'splace with a vent on the top of the tee. Vent the tee fast and the rad slow.

delcrossv

From the picture, the radiator isn't pitched toward the valve. You may want to pitch the radiator toward the valve, at least 1/2".

delcrossv

I've also cured this by going 1-1/4 out of the rad and using a 1-1/4 valve and a reducing coupling on the riser. To @EBEBRATT-Ed 's comment, you can also use a 1-1/4 straight pattern valve , and a reducing Tee with a 1-1/4 x 1/2 bushing for the branch vent. Since you're using a nipple you can center the rad under the window if you want as well. EVERYTHING needs to slope towards the riser.



Trick is to get the condensate out of the rad and into the riser, leaving room for steam on top of the condensate.

Miringanes

delcrossv said:

From the picture, the radiator isn't pitched toward the valve. You may want to pitch the radiator toward the valve, at least 1/2". 

I think it’s a bad wide angle iPhone photo, I have an 1/8” metal shim under the vent side legs and I got a level on it and it’s definitely pitched towards the valve. I originally had a few more shims under and the problem was actually worse, I’m assuming the greater pitch was pushing the runout from the riser downward using the valve legs as a fulcrum. 

delcrossv

Miringanes said:

delcrossv said:

From the picture, the radiator isn't pitched toward the valve. You may want to pitch the radiator toward the valve, at least 1/2". 

I think it’s a bad wide angle iPhone photo, I have an 1/8” metal shim under the vent side legs and I got a level on it and it’s definitely pitched towards the valve. I originally had a few more shims under and the problem was actually worse, I’m assuming the greater pitch was pushing the runout from the riser downward using the valve legs as a fulcrum. 

Gotcha. In that case, you may want to try the second method. When I did it I also had no movement on the riser.