2nd Floor Radiator Not Heating

nj88142

Hi,

One pipe steam system. Everything's functioning well except there is one radiator on 2nd floor not getting steam unless I force the system to run for more than an hour. The valve is fully open and I've run cycles with the vent removed. After reading here that the runouts can sometimes sag and pool water, I tried the suggestion to put 3/4 " blocks under the legs opposite the valve and 1/2" under the legs near the valve - it did not help. So I took the top half of the valve off and ran the system to try and narrow down where the blockage is. Air, and then, steam immediately came up the riser. There were some "puffing" sounds for 30 seconds or so but then they stopped. I put my finger inside the valve where it enters the rad and did not feel any blockage. The rubber seal in the valve is cracked but it doesn't look to me like that would completely block the opening into the rad. Pictures attached. If you advise to replace the valve, would appreciate any pro tips to make it easier to get the old one off. The ones I've replaced in the past were a bear to get off. Thanks in advance for your help.

Jamie Hall

You can just replace that cracked rubber washer on the stem — if you can find a good harfdware store or plumbing supply house.. Be gentle getting the nut holding it off…

nj88142

Thanks - that will save a lot of work. I'll check with the local plumbing supply Monday.

Waher

That looks like a hot water radiator valve and not a steam valve to me. Steam valves have a buldge to allow condensate, air, and steam to slip past one another without causing a blockage.

Big Ed_4

What is on the other side of the radiator ?

nj88142

Does this help?

Big Ed_4

Leave open the service valve on the left and remove the steam vent on the right . Throw up the thermostat and see if if heats up better .. No , the problem is in the riser . And if better , the problem is in the venting ….

If you want to shut off a radiator , better to plug the vent.

nj88142

Thank you for your suggestion. I was pretty sure it wasn't the riser because I had removed the top of the service valve and steam came right up. But I also thought I had run a test with the vent removed and when it didn't improve things I was convinced it was the valve blocking things. When I tried your suggestion to remove the vent, steam came up and into the rad quickly. I replaced the vent and it works fine. The failed vent is a new one (Jacobus MoM) and the 3rd new one (out of 10 new ones) that's failed over the last few months (Supply House has been good though about replacing them). Again, thanks much for your suggestion - it saved me a lot of unnecessary work!

neilc

bad batch of vents ?

one thing might be worth checking is the boler pressure, if it's getting too high you might be blasting that vent shut, locking it there, though I would think you would have others doing this also, so,

what pressure do you see at the boiler?

nj88142

Until a few weeks ago, the ptrol was not cutting out until almost 3 PSI (I didn't find that out until I started running main vent timing tests). I added a low pressure gauge and recalibrated the ptrol so that it now cuts out at 1.7 PSI. Pressures are running below 3 oz. (And majority of time below 2 Oz. during normal (non-cycling) boiler runs.

neilc

and the vent went bad after the Ptrol Fix ?

nj88142

No, that radiators been cold for several months but I incorrectly thought I had tested it without the vent and that it filled with steam and so was something more complicated that I didn't have time to focus on at that time.