Max EDR for 1”

JBFBMech

We are trying to fix a problem in an apartment building. They have a 70 EDR radiator on a 1” pipe. The vent spits when the heat comes on and the pipe bangs. We can’t run a bigger pipe and the tenant complains that the bedroom is too hot anyway. The solution I gave the owner is to put in a smaller radiator. When I look at my charts they say the largest radiator a 1” pipe can handle is 25 sq’. 25 is not big enough to heat the room. I have seen many instances where people have put radiators bigger than what the chart says the pipe can handle with no problem. In this same apartment they have a 60 EDR radiator on a 1” pipe in the other bedroom and it is working with no problem. Maybe I am reading the chart wrong. How big of a radiator can I put on a 1” pipe without problems? I can get rid of the radiator valve if that helps. The heat loss for the room is around 8,000 btu

Danny Scully

Have you followed the pipe back to the steam main? How exactly is it piped from there?

JBFBMech

I don’t know which one it is. There are several that come off that section of the main. Most of them come off the main 1 1/4”

Danny Scully

Try to figure that out. Horizontal run outs and vertical risers have different capacities. If the horizontal runout is 1-1/4” and the vertical riser is 1”, you have some room to play with.

ethicalpaul

Help me understand this question: why not just put in the smaller radiator?

If there's too much radiation for the current pipe due to too much condensation and steam trying to pass by each other in the 1" pipe, then what harm could come from putting in a smaller radiator, since the space is overheated anyway?

JBFBMech

I don’t want to put in a smaller radiator and then make the room too cold. If I go with a smaller radiator that is big enough to heat the room it will still be too big for the 1” pipe. I don’t want to put in a smaller radiator that is still going to spit.

KC_Jones

What size vent is on the radiator?

JBFBMech

“Try to figure that out. Horizontal run outs and vertical risers have different capacities. If the horizontal runout is 1-1/4” and the vertical riser is 1”, you have some room to play with.“



Even with a 1” radiator valve?

Danny Scully

No you’ll have to ditch the radiator valve and use a radiator elbow instead.

JBFBMech

“What size vent is on the radiator?“

Gorton C. Tried smaller vents and the radiator doesn’t get hot.

KC_Jones

How many floors up is the radiator?

SuperJ

8000 btu for a bedroom is a lot!

Fred

I don't suppose you have a way/path to add a 1" pipe out the other end of a smaller radiator and drop that drip into a wet return, do you?

JBFBMech

“How many floors up is tge radiator”

Radiator is on the third floor.

“8000 btu for a bedroom is a lot

That’s what the heat loss comes out to. Old windows and no insulation.

“I don't suppose you have a way/path to add a 1" pipe out the other end of a smaller radiator and drop that drip into a wet return, do you?”

Not easily

KC_Jones

Does it always bang or only when it's getting close to full, say beyond halfway full.

If it always bangs then I personally don't think a smaller rad will fix the entirely.

JBFBMech

“Does it always bang or only when it's getting close to full, say beyond halfway full.

If it always bangs then I personally don't think a smaller rad will fix the entirely.“

The whole time I was there it never banged. Going by what the tenant said. I did see it spit after it was hot.

Fred

I would expect it to start banging and spitting as condensate builds up in the radiator, maybe mid to end of a heating cycle because it can't get out of the rad. Once the heat cycle is over, then the rad has time to drain and get ready for the next cycle.

JBFBMech

They aren’t going to anything with it. They said it stopped spitting and banging after I worked on it. When I was there last I pitched the radiator because it was back pitched, but even afer I did that I still saw it spit.

ChrisJ

Best you could hope for at this point is running a small vent like a Gorton 4.

If it takes too long to get steam to the radiator, add a vent like a Gorton C or D to the pipe to vent that fast but keep the radiator slow.

clammy

Are u sure the supply valve is open completely and allowing for the rad to drain properly make sure the washer isn’t broken or disconnected from the steam it happens . Have u dis connected the raditor and see if the supply valve riser has play maybe both ends may need to be raised and one last note is the vent located properly on the raditor not where you would have a hot water bleeder valve a vent in that location is liable to spit by filling the rad w to much steam to fast .i would gather that most of the riser piping is concealed so if it’s not insulated or exposed to cold temp could be effecting the quality of steam your receiving wet steam in rads often cause spitting vents peace and good luck clammy