Reasons why there's no heat in certain parts of the building, and where to look for solutions

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naresh69

i have a home the last radiator on the 2nd and 3 floor that is all the way at the end of the main , the one at the 2nd floor heats up all the way just before the boiler shut down, the 3floor only heat up 4 or 5 across some times. third floor riser is one inch .2nd floor riser 1and 1/14. the boiler is 260,000 btu pennco 160sh series .two header they are seperated one goes direct to 1st floor 6 rad, second header heats up 2nd 3rd floor 12 rad .. when the boiler kick on the pressure gages goes to about 5 after all air is out of main vent for about 15 min the pressure goes to zero, pressure never build up after that .the boiler runs for an hour and then shut off all other rad are hot across other than those . can i have some info please

Jamie Hall

The comment on pressure is odd. It goes up to 5 pounds (which is way too much, by the way -- the pressuretrol should off the boiler at 1.5 pounds max) but then after 15 minutes drops to zero with the burner still running?

Very odd.

But... need to know a lot more about the system. Is this one pipe (typically one pipe into the radiator, and a vent part way up the opposite end) or two pipe (almost always two pipes into each radiator and no vents, though there are exceptions)?

How big (length and diameter) are the steam mains? Are there any vents on them? How does the water get back to the boiler?

How big is the boiler in relation to the radiation?

Some pictures of how the boiler is piped would help, too.

naresh69

thank you for your response .it is a one pipe system with two mains the main is about 35 feet long each . the vent is at the return next to the boiler i have two vent on each return .

naresh69

the supply line is 2 inch feed

nicholas bonham-carter

What size main vents are on the returns?—NBC

MichaelJohnston

I just had two steam traps replaced but that didn't fix the issue where these two particular sections of radiator are not heating up. The contractor suggests cutting the pipe to flush the runs. What do you do when you live somewhere where no one knows how to deal with your system?

Jamie Hall

MichaelJohnston said:

I just had two steam traps replaced but that didn't fix the issue where these two particular sections of radiator are not heating up. The contractor suggests cutting the pipe to flush the runs. What do you do when you live somewhere where no one knows how to deal with your system?

Next thing to do is to check the piping for any sags or dips which might be holding water -- that can block steam or air (so you need to check the returns, too) and usually also causes a water hammer -- but not always.

It is almost vanishingly rare for a steam main or runout to get clogged and need flushing. That would be about the last thing to think of. This is also true of the dry returns (wet returns can and do get clogged -- but you'd see that in dropping water levels in the boiler, rather than no heat). So cutting and flushing would be a last resort.

However, you might want to look and see how the air gets out of the dry returns for those two radiators -- where is the vent on the dry return for them, and does it work?

mickeylewis123

Thanks for republishing this article. I've have a problematic single pipe steam heating system. Each heating season i re-study Dan's books. In reviewing this article i picked up a couple of things i need to re-check - like having main vents 15" back from the T, how to tell if you have dry steam - i don't remember seeing this before, but it's good to know my steam is good - always a dry sight glass, and reminding me to insulate my piping. Much appreciated.

Kathiwithaneye73

Is it a normal practice to shut the boiler off entirely in an apartment building, during the summer months? No heat in the units themselves.