loud banging on steam pipes

mcp1

I shut down a valve in my son's upstairs bedroom, because it was getting to hot in his room. Now there is a very load banging noise coming from that riser, is that normal? Should I not shut down his valve, will it do damage? I put TRV's in the other bedrooms to regulate the heat, but in his room I didn't have enough clearance for it, so I just shut down the valve. What are your thoughts, thanks.

Fred

Is the supply pipe hot just below the shut off valve in his room? It may be possible that the valve doesn't shut completely and enough condensate has built up in the radiator that cool water trickles down that riser and hits the steam??? Turn the steam vent on that radiator upside down so that vent will stall closed and prevent air from escaping and see if that resolves the problem.

nicholas bonham-carter

Yes to the upside down vent solution, and keep the valve open.
Probably, your system needs some main vent balancing, and with more venting on the main, all rooms will have the same amount of steam.--NBC

mcp1

Thank you again, guys. I'm not sure how I would put more vents on the main because it is a cast iron pipe.

JUGHNE

Show us pictures of the main vents you have now...also boiler piping is interesting.

mcp1

Here is a pic of the main vent & the piping .

nicholas bonham-carter

Put one Gorton #2 for each 20 feet of pipe length, on an antler, plus the Hoffman there already.
This extra main venting, along with low pressure will balance the system better.--NBC

Fred

What Nick said about building an antler. You do need more venting on the Main for sure. To build an antler you simply buy some Tee's, some short nipples and some 90 degree elbows. Take that vent off and mount the Tee on that pipe, use you short nipples to space the vents out 4 or 5 inches, add as many Tee's as you need for the number of vents you use and at the end put elows to accommodate two more vents (1 at each end). That looks like a 3/4 pipe so you can use up to 3 Gorton #2 vents and the Hoffman or 4 Gorton #2's and no Hoffman. At that point you have about max'd out what the pipe can vent.
Make sure your Pressuretrol is set for Cut-in at .5PSI and the Differential is set to 1 (white wheel inside the Pressuretrol) so that Cut-out is no more than 1.5PSI

jch1

A visual example of what Fred is referring to can be seen at the below link, which I just installed in my system a few days ago:

mcp1

By adding those vents that should balance the system? This site is great! Thank you

jch1

I wouldn't be so quick to say that adding the vents will balance the system. Rather, adding the vents to your main allow steam to reach your radiators quicker. You may still need to modify the venting on each individual radiator to allow them all to heat up evenly.

If this is incorrect, somebody please correct me.

KC_Jones

Adding the vents to the main may ALLOW you to get the rads balanced. Until the mains are being vented fairly quickly you really can not get the rads balanced properly. The main vents themselves will not balance as has been stated already.

Fred

They help balance rads from one perspective. If you get the air out of the Mains quickly, all the rads on the system can start getting steam at about the same time. Poor venting will allow those closer to the boiler to get steam before the rads towards the end of the main can get any steam because the ssteeam is still pushing air past those rad runs to the end of the Main, so, some rads (the closer ones) are getting steam before the further ones and getting that issue resolved with proper Main Venting contributes to balancing the Radiators.
With poor Main venting, In some cases, especially if the rad in the room with the thermostat, is closer to the boiler, the thermostat may be satisfied before the ones at the end of the Main get hot.
Balancing the rads after that entails getting each rad controled with the radiator vent to the desired output you want for each room.