Steam Heating Problems

Randy Scott

We are working with a steam system that we are having problems with. The boiler is a brand new Lennox steam boiler with 3/4" & 1/2" periphal runs to the radiators. The boiler sets in the basement and this home has a basement, main floor, and 2nd floor. We are able to get steam and heat to every radiator in the home but the 2nd floor bedroom. This room has a 3/4" line going to the radiator. The radiator and steam trap are new. We have checked both the supply and return line and they are free. We have been able to get air and a cable through both easily. We are not getting any steam through the radiator. We have checked the room temperature and we should be getting steam through the radiator. The only way we are able to get steam into the radiator is if we hook a vaccuum to the return side of the radiator and pull the steam through the radiator. We have ordered your book, but any additional advice you could give us would be helpful. Your prompt response would be greatly appreciated as we are in western Nebraska and have seen low temperatures lately.

Paul Mitchell_2

I am not

as much of a steam Master as most of these guys. We mainly work on one pipe steam systems. But 3/4 and 1/2 lines to radiators seem very small. If you disconnect the radiator, does steam come out of the pipe?

Steamhead

That's a Vapor system

where 3/4 feeds and 1/2" returns are normal. I suspect either an air venting problem or a bad trap elsewhere in the system.

Feel the dry (overhead) return line. It should be warm when the system has run a while but not steam-hot. If you detect the presence of steam, follow it back to whatever radiator return is steam-hot. That radiator has the bad trap- and it might not be the only one. Make sure you find them all. One bad trap will pressurize the return and steam won't flow well to other radiators.

Also, in this type of system the air is vented at one or more central points in the basement rather than at the radiators themselves. If this vent goes bad it will show up as one or more cold radiators.

Are the steam mains insulated? If not, the vacuum formed as the steam condenses in the mains can actually pull the steam out of the radiators.

If you haven't already, get a copy of Dan's book "The Lost Art of Steam Heating". Chapter 15 is all about Vapor systems like yours. Have you found any manufacturer's names on the system components (valves, traps, any device in the piping around the boiler) that could help us identify your system? Take some pics and post them here if you can.

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