Heat coming from discharge side of Radiator

JC_14

So today I tried to trouble shoot why the radiator in our soon to be nursery is not working. 

Here are the details:  Recently purchased 1917 house with 2 pipe steam and air vents on all radiators (no steam traps). 1 upstairs radiator not working at end of line of 3 upstairs radiators.



Today I went through various trouble shooting:

Valve open

Slope of radiator ok, both steam supply and condense discharge on same side and sloped down towards discharge.

Inspected vent, air could blow through, soaked in vinegar, rinsed replaced

Cranked heat, vent working, all other radiators heated up, no heat from this radiator, noticed the discharge side was hot to touch, cool on steam supply/ valve side.

Checked slope of pipes in basement, condense/ return side looked good, steam supply flat/ slightly sloped incorrectly causing a slight water trap.

Felt steam supply pipe and warm to touch until 1 ft from vertical run to 2nd floor radiator.

Turned heat off, removed radiator, confirmed valve was fully open, blew back down steam supply side, a little resistance/ bubbling.

Water level slightly higher in boiler sight tube.

Reconnected everything, cranked heat,

Steam supply pipe warmed up past vertical run, upstairs steam supply still slow to warm up. Supply pipe warmer than before, however condenser discharge side becomes hot to touch



I think the steam supply pipe in the basement might be sloped wrong, but i thought if I cleared the pipe by blowing in it, it might work for a period of time. 

Any suggestions? We had the system inspected by the company on the boiler when we bought the house and we weren't impressed with them.

Thanks in advance.

JStar

Steam

Because it's in the nursery!



Are all of the radiator returns piped into a low wet return?

JC_14

Re:steam

Jstar

Yes. It also appears there is a vent on at the end of the low wet return prior to returning into the boiler. 

JStar

Steam

Are you able to post a few pictures of the radiator and the piping that leads to it? The return pipes, too?

JC_14

Radiator pics

Sorry about poor quality of pics but here are pics of the radiator and the supply line in the basement. Pic 1 of radiator. Supply and valve top right, return bottom right, vent left side. Pic 2 supply pipe in basement. The level is on the supply line, steam is running left from boiler to right where pipe runs vertical to radiator. Out of the frame to the left 2 T's that supply 2 other working radiators. The level is about where heat difference was first noticed. The return pipe is above the yellow wire running right to left. The return t's in with the other returns and drops into bottom of boiler. Would photos of that help?

JStar

Pictures

Yes, if you can take pictures of where the returns join together.

JC_14

Return pics

Joe

Pic 1 shows the return from top right to middle and down. The vent i noticed earlier is at that t. In the shadow to the left you can see the return from the other 4 radiators with a different style vent.

Pic 2 shows both returns joining together with fresh water going into the boiler. The return in question is the vertical pipe closer and to the left.

What else would you like to see?

JStar

Steam

The supply pipe that is sagging may be holding water and preventing steam from entering the radiator. The vents on the returns are also not needed. If this is a true two-pipe air-vent system, then the only vents should be on the steam mains and radiators. Whatappearsto be happening, is that thesteam is being blocked by a water seal, and the other radiators are allowing the steam to move backwards into the cold radiator's return.

Steamhead

I think this is an Orifice Vapor system

to which some knucklehead added radiator vents. Here's why:



1. Assuming all the radiators are the same large-tube style, they were installed sometime later than about 1925. By that time Vapor systems, with or without traps, had long since superseded the two-pipe air-vent system. Even in 1917, 2-pipe air-vent was rarely installed. And this system may not be original to the house either.



2. The vent tees where the dry returns drop toward the boiler look as old as the rest of the system. They would not have been used on 2-pipe air-vent.



3. Both the steam and return lines connect to the same side of the radiator. I've never seen a 2-pipe air-vent radiator installed like this, but it is not unusual on Vapor.



4. The radiator return connection has an elbow instead of a shut-off valve, and this looks like it's original. This was also uncommon on 2-pipe air-vent.



So if I were working on this, I'd remove the radiator vents and plug their openings. Then I'd vent the steam mains and dry returns well and install a Vaporstat, set at 8 ounces or so. After that, I'd correct any pipe pitch problems, and add orifices to any radiators that were found to need them.



Then I'd wait to hear of the improved comfort and fuel savings.

JC_14

Thanks

Jstar

Thanks so much for your help and diagnosis. I'll see if I can lift the sagging steam pipe.

I have some more questions but it could be that my brain is one for the night.

 When you say true two-pipe air-vent system should have a vent on the steam main where would that be? I looked down at the boiler and did not see any vents coming out of what I am guessing the main steam supply. Where would the main steam vent be located? If there is no vent on the main does that mean it is not a  two-pipe air-vent system? If so where can I find out what it is? Should we remove the vents on the return lines or if it works dont fix what's not broke.

 I was not impressed with the company that came down and did the inspection after we bought the house.

thanks again

JC_14

Thanks steamhead

I look to see if I can find more info on the boiler in the morning. I just realized that 1  of the downstairs radiators has steam in on one side and out on the other and no vent. the rest are in on one side and vent on the return side. Upstairs 3- of the 4 are plumbed like the one shown. the last one is in like down stairs with a vent.  All of the radiators are cranes.

my brain is done. thanks for the help i"ll let you know what i find out tomorrow.

JC_14

Update on progress

I drew out the entire system so hopefully this helps explain how the system is piped. The red lines are the steam supply, the blue is the return and the green V shows where a vent is located. I also showed which radiators were plumbed on the same side and which were not.



This morning we tried to get the correct pitch in the supply pipe in the basement. Its better but not right.  When I fired up the heat I was able to trace the heat with my IR thermometer.  The supply pipe to the radiator heated up past where I thought the water seal was. In fact it was hot up through the ceiling in the basement. Unfortunately at the radiator the supply side only warmed up to about 75 before the dining room with the thermostat was at temp.



I did notice that the return of the front hall radiator was quite hot (205 ish). That heat traveled down to the main return and then back up the return for nursery radiator. The return did not get as hot as it did in the past.  Could the heat coming back up the return slow down the steam from the supply side? Is the hot return due to the proximity of the radiator to the boiler (its the closest) or is it because it is the only radiator with out a vent?



Is this a case of the system was knuckle headed before my time and I need to find orifices for all of the radiators or should I try to balance the system by swapping out vent sizes?



Thanks again

Steamhead

"Could the heat coming back up the return

slow down the steam from the supply side?"



You bet it could. It's closing the vent on that nursery radiator, at which point no more steam can enter.



I ran into this a long time ago, on a one-pipe system that had a single two-pipe radiator, and wrote about it:



http://www.heatinghelp.com/article/325/Piping/246/Steam-Stumper



You're right- this system was knuckleheaded before you got there. But now you can make it work just like the Dead Men intended. Get rid of those radiator vents, orifice where needed and keep the pressure low.