Old metal Fin type Steam radiator !?

kacrejam

Hi All,

I have a 2-pipe steam residential system. The house is old and the 2 rads in question are in a sunporch. I am wondering what kind of radiators these are and whether best to replace? They seem to be some kind of metal fin-type radiator?? All of the other rads are your "normal" cast iron type. Do these conduct steam heat well? Is there some kind of maintenance that should be done on these?

Jamie Hall

Those things work just fine. The only maintenance they need is to vacuum out the fins from time to time -- they do collect dust.

And of course, make sure the trap is working!

You do still have the front panels for the enclosures?

kacrejam

Jamie, Thanks for the advice. How do I make sure trap is working. Do i need to open up the trap?

Yes, I do have the front panels for it. I had thought maybe to replace with new rads (and maybe get rid of the panels if nice new rads are bigger than the space) but sounds like I am ok.

Jamie Hall

Traps are easy. Get the system really running, so that the radiator is hot all the way across. Then feel -- or better, take the temperature of the outlet above the trap and below the trap. The pipe below the trap should be appreciably cooler (10 to 15 degrees is typical). If the radiator won't heat, or heats very slowly, the trap may be failed closed. If the pipe below the trap is as hot as the pipe above it, the trap is failed open.

Steamhead

They'll work- but since your other radiators are cast iron, they might not work as well. Where are you located?

kacrejam

I am going to test the traps as you described. Thanks for the great info.

I am in the southeast PA area near Villanova.

Jamie Hall

Villanova isn't impossibly far from Baltimore. I you really have trouble, you might persuade @Steamhead to come that far...

Fred

Why are there vents on those Rads? Also, it may be an optical elusion or the way you took the picture but that second rad looks like it may be very slightly pitched back towards the supply side??

Steam

Fred is spot on. I've seen single pipe systems with those finned radiators. They work just fine.

Pitch in second picture is off as Fred said.

Danny Scully

There also shouldn't be the need for vents as @Fred questioned. It may be a sign the traps have failed.

DrilonBuleshkaj

Does anyone have any technical specification of these type of radiators? I need it to find the heating capacity for this type of radiator for a study report!

Hap_Hazzard

These units pack a lot of EDR into a small package, and when the airflow is unobstructed, they can heat up a room in a hurry. The trouble is, because they have less mass than a cast iron radiator, they don't hold heat very long. If the radiators that are controlling the thermostat are cast iron, you might notice that it gets a little chilly waiting for the heat to come back on. But before you consider replacing them, you'll want to take a look at availability and cost of cast iron radiators. It's hard to find good used ones, and new ones are expensive.

ChicagoCooperator

I think there are some tech type specs in the "museum" on the site. One thing I notice is that the convectors don't fit tightly in the recess - there is some open area at the ends. I wonder if originally there were slightly longer elements in the recess. One thing to be aware of is that the output is based on the height of the chase above the convector when you look up the EDR. What do the front panels look like?

Ceeb

My daughter and son-in-law just purchased a house built in 1825. The entire house is heated by this type of steam radiators. None are recessed. All are proud of the finished wall. Can someone give me an idea of the vintage of these units? I'm assuming the original ones were cast iron. None of them have shutoff valves or vents.

bburd

@ceeb Are you sure the system is steam, not hot water? If you post a picture of the boiler showing the gauge and nearby piping, we can tell you.

Those are called cabinet convectors.  They were common in cold climate single family homes from the 1930s through the 1950s, and in apartment buildings into the 1960s. They are still manufactured but are used today mostly in non-residential buildings like schools. 

mattmia2

They most likely either replaced cast iron radiators to "modernize" the building or it didn't have central heat until mid 20th century or so.

Ceeb

I am assuming they are two pipe steam radiators. I say this because there are no pumps coming of the massive 26 burner Burnham boiler. Boiler has two supply lines coming off the top of it and return lines on the side. System seems to run at about 4psig according to the gauge. I'll get a picture of the boiler and the inside of one of these cabinet convectors and post tomorrow. Thanks for the reply!

mattmia2

I din't see the pictures. That is 2 pipe steam. There is a steam trap on the convector. 4 psig is way too much pressure, your system will be happier if you lower the pressuretrol. You might find what was broken that caused them to crank the pressure up.

Ceeb

I hope my pictures attached OK. I think these cabinet convectors may be replacements, as you say, from old cast iron types. The original heating system was fireplace of course and I see evidence of floor grates that were removed and original floor pine board patches to fill the openings in the front foyer and both front rooms. Could these have been from the first "modern" heating system and that being a passive hot air system delivered through floor grates in the first floor? Most likely coal fired furnace?

mattmia2

It could have been a gravity warm air system but it is more likely there were indirect radiators below the floor that were later replaced with convectors. Are there cast iron radiators on the upper floors or convectors there too?

bburd

That is a two pipe steam system. That big hex nut at the top of the return pipe at the left end of your convectors is a steam trap. I don’t see supply valves at the convectors, which is unusual.

Four psi is definitely too high, you want less than two unless you have a vapor system, which runs on ounces of pressure.

Ceeb

The entire house are the convector type. This includes a third floor on the back part of the house. I took a cover off a third story unit and it was the same story, no inlet valve, but has a steam trap also. What is the purpose of the steam trap on the condensate side of the convector?

Jamie Hall

Same as usual -- keep steam out of the return, but let air and condensate get back to where they belong.

Ceeb

Thanks all for your comments! Very helpful.

Ceeb

Hi again. My daughter purchased an old home with a 2 pipe steam system and cabinet convectors last winter. All the convectors were getting hot. Turning on the boiler just yesterday as it is getting cold, 4 out of the 14 convectors are not getting hot. What would be the most likely cause. All convectors have steam traps.

neilc

I've seen where traps will stick shut,
with boiler on, try wrapping the trap lightly, just enough to shock it awake, see if the cold rads heat up,
with the boiler off, try loosening the cap a little, doesn't have to come all off, use 2 wrenches, this will also jar the trap and wake it up,
or there are deeper issues to be discussed later,

Ceeb

Thank you, I'll give it a shot!

neilc

went back and read the whole thread,
were you able to dial down that 4 psi running pressure?
that is too high and could have "Stuck" the traps

mattmia2

That one pipe air vent on that one convector means something is up, either that trap isn't opening to let the air out or wherever the air is supposed to vent once it gets in to the return isn't working or other traps are failed open and filling the returns with steam and causing the trap to close(from steam from the return rather than from steam from the convector)/blocking the air from venting. If there is steam in the return before the air is out, the air can't pass through the steam.

Now that I write this, my bet is on other traps failed open and filling the return with steam and keeping the air from vnting.

Look for traps that are very hot on both sides, those are not closing when the steam reaches them.

neilc

both sides of the trap argument / discussion,,,,,

Matt makes a good point,
at the cold rads / convectors, is the pipe under the trap hot,
much hotter, steam hot, compared to the cold rad / convector?
then Matt is correct about others failed open.

now to find them

Ceeb

Still seems to be stuck shut after some taps to try to get it to open. I found a box full of Tunstall thermostatic capsule replacements still new in boxes. Part number TCDB-1301. It seems previous owner had replaced some of these in the past, so had a supply of about 10. Steam traps are Dunham V1B units and these are the capsules for rebuild. The previous owner had a large supply of replacement parts for the Pressuretroll and other parts of the Dunham boiler so this find was fortunate. I think I'll replace one of the convectors that is not heating up and see if that cures the problem on the cold ones. The previous owner purchased the house in 1968 and had all the documentation and even the book about steam heat you see advertised in various places. Can't remember the title, but it is brown and white.

Ceeb

To answer question above, I was able to get Pressuretrol down to 2psig. That seems to be the lowest I can get the 26 burner Durham boiler to run at. New question, does anyone have tips on how to get the screw top lid off of these old steam traps? I have tried using two pipe wrenches and can't get them to budge. I now wonder if they have ever been removed. Some of the trap internals are definitely stuck shut, as some convectors will not heat up in this two pipe steam system. I have a box of 10 new Tunstall capsule replacements that came with the house, but I can't get the dang traps apart!

mattmia2

If they are all the same size I would buy a 1/2" drive socket and breaker bar that fits the cap and get a big adjustable wrench or open end wrench to fit the trap body.

The convector could be not heating because its trap is failed closed or because a trap somewhere else is failed open and letting steam in to the return and the steam in the return is blocking the air from venting from the convector that won't heat or is heating and closing the trap on the convector that won't heat. The failed open trap could be on a convector or it could be on a main.

reggi

bburd said:

That is a two pipe steam system. That big hex nut at the top of the return pipe at the left end of your convectors is a steam trap. I don’t see supply valves at the convectors, which is unusual.

The supply inlet is Dunham's adjustable regulator fitting..  There should be something in the Museum on them

JUGHNE

For trap caps, the exact size socket and a 1/2" impact driver will loosen them.

I would always put a back up wrench on the body..... just becauses.

Ceeb

Thanks for the tips! As always, this is the best place for a novice like me to gain knowledge. It sure is tough to find a heating person in my area that knows about steam heat. Regards to all.

mattmia2

Looking at the pictures of your convectors, you might need to break the unions on the convectors and remove the convector to get enough access for particularly stubborn ones.

Ceeb

Thank you mattmia2, that is exactly my situation.

Ceeb

Thanks for the comment about the Dunham regulator fitting. I did find a spare fitting in a box in the basement that had 197A stamped on it. I found it in the Dunham catalog in the heating museum as you suggested. Can these be totally shutoff so that no steam enters the radiator or can they get plugged up with deposits preventing the same?

mattmia2

They can fail closed and prevent the convector from heating. Another trap somewhere else failed open can put steam in the returns and prevent other convectors from heating as well.

Ceeb

Thanks, looks like I have a lot of checking to do.