Installing the correct size (steam) main line valve

John_28

To all concern:

I have a single pipe residential steam system. I recently redirected an existing feed line to an existing radiator on the second floor due to construction. The radiator was supplied by a 1 1/4 inch feed line. I reduced it to a 1 inch feed. Im now getting water hammering and the radiator valve is spitting water. The pitch on the radiator is at least 1 1/2 inches tords the supply. Should I install another main vent valve or should I just move to Florida. I like to thank ALL for taking the time with the above mention. Thanks John

Unknown

a 1 1/4\" valve will supply a 55 sq ft radiator.

1" isn't generally used for one pipe steam, for the reasons that you described.

Noel

Tim Gardner

My 1925 house has 1" pipes supplying the smaller radiators in the bathrooms. In one case the pipe's run is very convoluted, going through at least five one inch elbows and several long horizontal runs with very little slope before getting to the radiator. I would not have believed it could work, but it does and works fine.

So if you reduce the size of the radiator so that less steam needs to get through, it might stop spitting and banging. However, the room might not get warm enough.

Tim Gardner

Slower vent might be worth a try

Another idea that would be worth a try: put a slow vent on the radiator. Maybe that would slow down the steam enough to stop the banging. Not likely, but cheap and worth the shot. (If I recall correctly, Hoffman #40 is a slow vent).

scrook_2

pipe pitch

you say the radiator is pitched right but (other than being smaller than before) are all horizontal runs in the new riser pitched enough? I take it 1 1/4 pipe is not an option. Can the riser be insulated (if it is not already) to at least reduce the condensation forming in it?

clammy

pipe

did you run steel or copper pipe if copper you should insulate it and re check your pipe pitch ,what your pressurtol set for 1/2 cut in 1 lb cut out is your rad pitched towards your valve what type of valve and did your install a bushing in the rad that might make the rad hold to much condensate and cause water hamer when it finally comes back you may have to install a seperate drip for that riser don't give up to easy good luck