One Steam radiator will not heat !

Bill Webb

I have a radiator in a third floor bathroom that will not heat. I first acquired this job about a month ago when another contractor filled the system with water thinking it was a hydronic system. (it's 2 pipe steam) After draining the system down to about midway on the sight glass the customer now was getting heat in most of the house. I also adjusted the pressuretrol back down to about 1psi. In the weeks ahead I found out that the owner lived there for about 30 years and did not think the traps were ever serviced.
We repaired all of the traps and changed about 9 angle radiator valves that could not be opened or closed. (an apprentice and I) All three had heat except for one radiator in a center third floor bathroom. Radiators in the front and rear of the same floor heat but not the middle one. The riser feeding this radiator also feeds a radiator in the first floor dinning room and a second floor bedroom. They both heat. I tried closing the valves on the first and second floor radiators and this caused the supply pipe leading to the third floor to heat up maybe 6 feet above the second floor. When the pipes enter the ceiling of the second floor (10 feet) they run horizontal through the floor about 5 feet before connecting to the radiator. In the second floor bedroom the pipes also run horizontal about 6 feet after the radiator but this is on the outside of the wall and I raised the condensate return so the pitch would drain the water back. Someone told me to raise the pressure (which I did not think would help) and it did not help. I think the problem may be in the horizontal pipes in the third story floor. Could they be clogged with rust from improper pitch? Can I blow them out with dry nitrogen??? Any help would be appreciated ! Bill Webb Zien Service Milwaukee WI

[Deleted User]

see if the steam

makes it to the radiator by disconnecting the inlet valves union. if it then does, then you may very well have a plugged return pipe. after the system was flooded, some ''mud'' may have been packed into the pipe...the weight of all that water could have sagged a pipe also...

steve_6

I agree with gerry

Check that supply to the radiator as Gerry says, and also check the return in the same manner you may have an obstruction to the trap.You may also have another steam trap that is bad, possibly stuck open, letting steam pressurize the return. Check the radiators before and after the one not heating for this problem. you may have some sludge in the return that needs to be flushed out.

Bill Webb

opening union at radiator valve

My apprentice did open the supply union and the trap but never got steam out of either, just gurgling noise. (I was gone and my apprentice was finishing up when he discovered the problem)
After closing off the other 2 radiators on the same riser the home owner said one pipe on radiator was slightly warm. I will be going back this week, if needed what is the best method to flush the condensate return line for this radiator. Thanks for the help! Bill

Steamhead

I think Gerry and Steve nailed it

I'd run a hose to the rad and flush both supply and return with water under street pressure. If this doesn't clear up the problem, you may have a mis-pitched pipe which you'll have to get at somehow.

This would be a good time to flush out the wet return as well.

When you're done, check the vents on the steam mains and dry returns. If they're not working properly, the system will heat slowly- especially on rads far from the boiler.

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