Water Hammer Question

STvex

Hi, I am having trouble shooting water hammer I am hearing from one radiator. I have all of Dan's books but can't get this one. I have a one pipe steam system, main insulated except for the room in picture where it provides heat, pressure less than 2, mains have gorton 1's. The one inch pipe in the middle of the room goes towards the dining room and has water hammer near the location where the supply valve connects, very loud when the boiler fires multiple times such as the current cold weather we are having. Over 32 degrees, i don't hear it that much. Before I had a sag where the T connects to the main pipe. I strapped to try to level it. The banging sound became a little less because of it but it still happens. The radiator had a Gorton 5 that I changed to Gorton 4, instead of banging all the time, its only when its real cold outside. I have a White Rodgers thermostat but I can't control the cycles per hour on it. I know one per hour is ideal. Should I change the Gorton 4 to a Gorton 3 on the radiator? Should I change the thermostat? What do you guys think? It's only one radiator that has banging issues, i have a total of 9 radiators. As always, your help is appreciated. Thanks.

Fred

Is that supply valve fully open? Is the supply run to that radiator, at the supply valve area pitched enough? It looks like that radiator run has been bushed down at the Main. Has it also been bushed down at the radiator? What kind of radiator is on that run? A 1" pipe, on a 1 pipe system is pretty small to both carry steam and return water. If the radiator inlet has been bushed down, it is very possible water sits in the radiator until it get high enough to overcome that bushing. Let's see what kind of radiator is there and the inlet connection.

KC_Jones

Are you positive that pipe to the rad is pitched back towards the main? It seems pretty tight to the ceiling so hard to see it having much pitch. It should have roughly 1" for every 10' pitch.

Jamie Hall

Somebody did a nice job of getting that pipe right up to the ceiling -- vertical T, nice little nipple, 90 degree el...

And I would be astonished if there was enough pitch on that runout.

STvex

Answers to Questions, first of all thanks for the replies
1)Yes the radiator is bushed down from 1.25 to 1 inch at both the main and radiator. That was a sharp eye.
2) Supply value, brand new, fully open. Radiator pitched towards supply pipe, verified with level.
3)Picture of radiator and valve attached.
4)Where the pipe runs, there's no sheet rock there, hard to see from pic but i have space to push up. I will try this. The only hard part is, the pipes turns after it goes into the closet then goes to back of house but i should be able to get a pitch.

So what are my solutions:
1) Can a plumber cut out that bushing and replace it with a 45 degree 1.25 elbow and replace the one inch pipe with 1.25 pipe?
2) Do i take out the reducing bushing at the radiator and replace it with some other type of reducer from 1.25 to 1 inch?
3) Pitch the run which as much as a i can which i will this weekend.

Fred

My personal opinion is if you could take the bushings out of both ends and replace that run with an 1-1/4 pipe and valve you'd be much better off. I'm not even sure a 1" pipe can supply enough steam to heat a radiator that size, let alone provide enough room for return water.
The second choice is to take that bushing out of the radiator and put a 1-1/4 valve and spud on that radiator so water doesn't pool at that spot. You can then bush the bottom of the valve down to 1" to fit the existing pipeand that won't let water pool there. I don't like this approach because the supply pipe is still just 1" when the radiator was obviously sized for a 1-1/4' supply.

KC_Jones

I just looked up the ratings for 1" pipe and valve and it is only supposed to support 20 sq ft of EDR in a counter flow situation such as yours. My rough estimate is that rad is around 50-60 or so. This could definitely be your issue along with the pitch.

STvex

thanks so much, you guys nailed it, i would have never thought about the capacity of the one inch pipe. It seems like Fred's second option is easiest to do. My other options seems to be either get a smaller radiator or change the piping. can I cut out the bushing and install 1.25 pipe in that tee on the main without anything else breaking? I am not sure it it will just twist off.

Fred

I suspect you will be able to get that bushing out of that Tee without much problem. Putting in the 1-1/4" pipe is really the only way to do it right. I have one of those tube style radiators and, in my opinion, they are the best for even heating and heat retention.

STvex

Thanks guys for the feedback and advice.