vapor venting and radiator piping

dobro23 · November 2018

thanksgiving is a great day for vapor discussions!. i put in a megasteam about 8 years ago for a customer who has since moved to a new house. there were a few problems with the existing boiler ( and system) but once it starting leaking all over the floor he finally decided to buy the new machine. anyway, one or 2 problems never went away and i was called there yesterday by the new homeowner to revisit these issues that they thought were new. so in a nutshell, there are 2 radiators in that dont heat. like ever. these are the only 2 radiators in the entire house where the steam is supplied to the bottom of the radiator through regular hot water style modern radiator valves. the condensate returns of the radiators are just 3/4 elbows. no orifices. the vaporstat is set to 6oz with a 4 oz subtractive differential. heat everywhere else is perfect. the suspicion is that the kitchen was added onto and these are not the original radiators. i believe they were replaced years ago since all the piping to them has teflon and they are shorter than all other radiators in the house. most likely to fit under the windows. so in an effort to get these radiators th heat i have a few options and not sure which is best. 1. pipe the steam supply to the top and leave the condensate where it is. this will match the other radiators in the house but will still have a regular radiator valve. not sure is a calibrated vapor valve is still available. (im sure i can calculate an orifice and stick that in the union... ) 2. what if i remove the return elbow and replace it with a steam trap? with that work? 3. what if i remove the condensate return entirely, pitch the radiator the other way and add a radiator steam vent essentially making it a 1 pipe radiator? 4. something i havent thought of? I also have a few questions with the main venting. currently the steam leaves the boiler in 3" for 15' and them splits to 2 2" mains. i main is 45' and the other is 25. these mains come back to the boiler and have vents on them before they drop into the hartford loop. the condensate returns follow the mains around the house and tie together in the ceiling before they also drop into the hartford loop and there is a main vent on this pipe also. no f&t or any other traps in the system. so are these vents correct in placement? should i take the ones off the mains and put a huge one on the condensate return only? should the condensate return not have one at all? the pics im sending are not great and dont criticize me on the insulation. it was the homeowner. but at least he tried!! 1st pic is of common to all the radiators in the house except for the 2 not working. 2nd pic is the 2 not working. 3rd is a pic of the main vents. the 2" is the main and the 1-1/4 is the condensate return. there is another 2" main not pictured which also has a vent. other pics are just for clarity.

Fizz · November 2018

I am a home owner who spent much time on this site to learn as much as possible about my system, a Richardson, which is vapor/vac, similar to your customer's. Ironically, my system had add-on kithchen(2 rads) and bathroom(1 rad). Both were piped as typical 2 pipe with supply on top and return opposite bottoms. They work fine, but I have since put system in vacuum by replacing the 2 main vents with MEPCO quick vacuum vents, and using hot water setting of 3cph on t-stat. Warm, steady and comfortable. Don't know if you have Richardson, it calls for return to be on same side of supply, unless length of radiator is greater than height. Hope this helps, but you will get the best feed-back from the many pros/experts on this site.

JUGHNE · November 2018

The 2 returns tie together above the water line and drop in only one pipe?
The quicker return will close the air vent early and the other return will still have air in it. This might keep some rads from heating....just a hunch of what might be wrong with piping.

dobro23 · November 2018

yes. the 2 1" returns tie together at the ceiling at a tee which increases to 1-1/4". then there is a hoffman #75 and the drop to the boiler happens a foot or so after . in the pic, the longer return comes through the wall on the right. the tee you see immediately after pics up the shorter return in it's branch connection. the larger run connection travels left to the vent and the drop.

Steamhead · November 2018

Is there anything that might trap water in that return line, such as a water pocket?

dobro23 · November 2018

@Steamhead ~ looks pretty normal to me. no obvious sagging pipes or traps or places where water can collect. customer says system is silent as far as water hammer. im 99% sure that the supply valves are a metering device and 95% sure that the return elbows are just REGULAR elbows although the one i have a picture of does seem suspiciously new. pretty sure i checked out the others year ago when i replaced the boiler though and found nothing weird in them. the "central air eliminator" has been replaced with a hoffman #75 but the original fitting ( which looked like a turtle shell with a salt shaker on top) is still at the house. pretty sure i dont need to put it back on, but it's there. the picture shows it installed in the original fashion before the boiler was replaced. that said< if that is a central air eliminator, then the system was not designed to have main vents before the drops back into the boiler? there are vents there now because there were plugged tees so i assumed! might need help tweaking this system back to its original design one step at a time!

Steamhead · November 2018

Does it say "New York Heating & Supply Co" on the top plate of that valve?

EBEBRATT-Ed · November 2018

I agree with @Jughne that the condensate returns should tie together below the boiler water line and each have a vent at the top of the risers

dobro23 · November 2018

@steamhead ~ not sure. I'll have the customer check or i will when i get back there in the next few weeks after i decide what to do. here is a better pic of the valve itself. it looks like it says new york something on the ring with the graduations on it. youcan sort of make it out in the pic. the valve body itself looks like TS. idk what that is.

dobro23 · November 2018

but as i said before ALL of these radiators work perfectly. it's only the 2 in the kitchen that appear to have been reworked and replaced that dont heat at all. i'm thinking that by piping to the top of and returning on the opposite bottom is all i really need to do. that and add an orifice of some sort since these valves are modern.

Fred · November 2018

In addition to what has been said about the returns needing to tie together below the boiler water line, are those two radiator pitched towards the return side of the radiator? If not,they too could be holding water.

KC_Jones · November 2018

Are you getting steam to the inlet of the radiator? If the rad isn't heating at all and you aren't getting steam to the valve, why do you think changing the rad piping will fix it?

IMHO changing the rad piping might help it heat better if it was heating poorly, but if it's not heating at all I think your issue is in the basement. I'd start there, certainly the returns tied together could be part of it. Check all the supply piping and find where the steam is "stopping" then that really should tell the tail.

dobro23 · November 2018

@KC_Jones ~ yes there is steam being supplied to the radiators. i physically removed both the supply and the returns from the radiators to verify and heck for clogs etc. perhaps it is heating so poorly that it isnt heating. i think there are several things that need to be done. repipe the steam supply, remove or add main vents, drop the returns separately. hopefully i dont create more problems!

vapor venting and radiator piping

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