Steam heat has lots of hammering since getting return replaced and hot water heater changed (photos)

Old_Steam

Hey folks - i just found this great site. My house has an older natural gas fired steam boiler with single pipe radiators throughout the house. My old steel pipe return line from the 1950’s finally rusted out along the floor and i had it replaced with copper. While he was there, i had him change out my hot water heater, which was 16 years old. The next day, whenever the water level in the boiler gets down to the level of the Hartford loop connection, it hammers like hell. It sounds like the system is ripping apart. If i crack the valve to add water from the hot water heater (no automatic feed in this old girl), the hammering stops. The strange thing is that when the water level dropped to the Hartford loop before, it never made any hammering noise.

I believe it has something to do with the new return line, or the hot water heater. He did have to jam the new water heater in and the old outlet pipe that tee’s off to feed the boiler is now slightly pitched up before heading down to the Hartford loop, where it feeds the boiler.

I tried to set my pressuretrol down from 6 pounds to around 2. I didn’t realize I had it so high.

Here are a few photos that might show what my issue is.

Thanks for any attention and ideas you share.

Danny Scully

Oh the horror...the Hartford Loop connection need to be a short nipple (close or shoulder). I use a street elbow. Additionally, 1/2” is too small...it also makes me wonder what size the wet returns are. Are they 3/4” or 1”? For your pressuretrol, the white wheel should be 1.5 while the CUT IN should be 0.5. 

KC_Jones

Whoever piped that did it incorrectly. As said that connection is supposed to be a short nipple, also they reduced the pipe size by adding that bushing. To get rid of the hammering it need to be redone properly.

How often do you add water to the boiler? Excess make up tends to be bad for the boiler.

Of note for any future boiler replacement, that header piping is also incorrect.

The venting on the water heater is not correct. The vent pipe is supposed to pitch up towards the chimney not down like it is. You actually have a dangerous situation there. I am pretty sure that flexible aluminum isn't allowed by code or the manufacturer, someone with a bit more experience may correct me on that one.

I think you need to find a new plumber, considering they can't even install a water heater correctly.

Old_Steam

Should the sight glass/boiler water level routinely go below the level of the Hartford loop tie-in? If not, can it cause hammering?

ethicalpaul

I was actually going to respond "what hartford loop?" because I didn't even recognize it. I thought that was the water fill connection.

The Hartford loop should either be a few inches below the waterline, or in the case of the Gifford Loop alternate, it can be a few inches above the waterline. The hammering problems seem happen when it is right at the waterline.

Chris_L

And what about the LWCO? It looks like it is mounted very low and won't shut off until the water level is below the bottom of the sight glass.

Old_Steam

That McDonnell & Miller #67 LWCO is connected with the T fitting that it came with. It is connected to the lower base of the sight glass pipe. That is the intended location, as far as I can see.

EBEBRATT-Ed

Pretty horrific. The guy that did that knows nothing about steam,or water heaters apparently. He should have bought a shorty for the water heater, venting is bad. Does this guy even have a license?

The LWCO is ok it's a #67 mounted on the gauge glass tappings that's the only thing that's right

Looks like he use 1"? copper for the wet returns, don't know if that's large enough but it needs to be brought up closer to the hartford loop and installed with a close nipple and it has to be full size of the return

Imagine all that return water trying to get through the 1/2" with the steam slamming it??

Old_Steam

Is it ok for the feed that puts water into the boiler from the hot water tank to get added through the Hartford loop connection? Thats how the previous guy set it up about 20 years ago. This recent guy just reused the setup that was there.

KC_Jones

Feeding the water there is perfectly fine, what isn’t fine is the length and size of the pipe connection.  He put a busing into that tee and reduced the pipe size.  That and the length will cause banging.

Old_Steam

Would a pressuretrol setting of 8 PSI also add to the hammering? I only noticed that it was set that high after i read on this board yesterday what the proper setting should be. I lowered it and I am calling for heat again to see if it gets the hammering. I also raised the water level about an inch or so over the pseudo Hartford loop.

KC_Jones

Lowering the pressure might make it milder, but won’t necessarily solve it.  Raising the water level might help, but I doubt it has a huge impact either.

Nothing you are trying hurts, so I say see what happens.

Jamie Hall

8 psi certainly wouldn't help the hammering. Worse, it may have damaged all your vents and traps; most of them are rated for 3 psi working pressure.

Old_Steam

Those things I tried have helped so far. I think, because the pressure was up so high, that it would force the steam out through the Hartford loop and hit the cold water in the return line. The system cycles now, instead of going from 60 degrees to 68 degrees in one shot, with an hour of straight boiler-fired steam.