3rd floor venting

DK27

I have a 1 pipe steam system with two mains and I am currently unable to properly heat my third floor radiator on most heating cycles. With the exception of the third floor I think I am pretty well balanced, all my near boiler radiators have #4s, the 2nd floor has #5 and #6s  and it allows all the radiators on first and 2nd floor get heat at the same time.  I've put a D on my third floor radiator with little luck of getting much heat there unless it's a very long cycle. The run to the third floor is very long, not only does it go up 2 stories, but also semi-horizontal for another 15 feet.  I am not sure if I'm approaching this right but I know I have to get the air out of the run quicker.  Would it be better to tap my radiator and add a second D vent or tap the run and add a main line vent? If I were to use a main vent on the run do I tap near the radiator valve(before/after valve)?

BobC

last rad?

Is the third floor radiators one of the last takeoffs from the steam main?



Does the end of the steam main get filled with steam quickly?



If you have someone around to help you try this. take the air vent off the radiator on the third floor and see how long it takes to get steam out of it. make sure someone is standing by to shut the boiler down when theam does come out of that vent hole.

DK27

main question

It is the 3rd run of 6 in total coming off that leg of the main.  About a month ago I created an antler system for my mains with 2 Gorton number 2s and 1 Gorton number 1(left-over from original setup) per main. I've timed how long it takes to get steam to the ends of the mains and it's about a 1 min 45 seconds. I tried to stick to the addage of vent the mains quickly, radiators slowly.   I will have to try the steam out of the radiator test this weekend. 

DK27

Steam to 3rd floor radiator

I just ran the test of how long it takes steam to get to the end of the radiator, and it was 19:52 from the time the boiler started making steam. 

BobC

Wrong pipe slope?

It took almost 20 minutes for the radiator to fill with steam with the vent off, how long did it take for the inlet to the radiator to get hot?



It sounds like you have a pipe that's not sloped correctly somewhere on that radiator and that is blocking most of the steam. have you taken the radiator off to make sure that inlet valve is working? It could be failed in the all but closed position.



How many sq ft of steam is the boiler rated at and what is the total EDR of all the radiators on the system? Does the piping in the cellar have insulation on it?  Has this radiator always not worked or is it somewhat recent?



Bob

DK27

answers

Not a new issue, just how it's always been on the 3rd floor.  I spoke with the previous owners and they said they just ran a space heater up there, which i'd rather not do.  Last year I insulated the mains and as much of the runs as I could with 1.5" insulation.  The time I gave was for the the steam to reach the end of the radiator, now that I think of it, a better test would be the time to the start of the radiator, i'll test that tonight by check how long it takes for the inlet to get hot. I am not sure about the pipe slope from the radiator to the top of the vertical run on the 3rd floor as most of this is burried within the floor, but the steam that was coming out of the radiator was continuous without spitting, gurguling, etc., not sure if that indicates anything either way though.  I've definitely tried to balance the system and have recently increased my mains venting, and changed my radiator vents, and right now all the radiators on the first and second floors start to get heat at the same time.  The third floor has just no coopoerated. 

BobC

Force the steam to the third floor

For some reason it's easier for the steam to go everyplace else but up to the third floor so maybe everything else has to be slowed down some to make the third floor more attractive.



Your venting rates are pretty slow now, what happens if you turn the 3 most aggressive vents upside down (effectively shutting them down). Does that make any real difference on steam getting to the inlet of that 3rd floor radiator? This obviously is no solution but it may let us see what is going on.



have you tried lifting that whole radiator up onto 3/4" blocks to see if that helps? Use a lever and fulcrum so you can do it gently and have some help so they han slide the blocks while you lift (gently - don't want to break anything).



We still need the boiler sq ft of steam and total EDR numbers just to be sure that is not an issue.



Bob

DK27

third floor

I calculated the BTU drawn of all the heating sources in my house(I have steam and radiant heat running on the same system), at almost 81k BTU.  My boiler is a Weil Mclain EG 40 that produces 125k BTU so I don't think my boiler is undersized.

I still have to run the time for steam to get to the inlet and again when i close the three biggest vents. 



Thanks again for your great insights.