Steam Hammer, Not Sure What The Cause Is

nate70500

I have some steam hammer coming from a section of my heating system. It is a one pipe steam heating system in an old house (built in 1851). The hammer noise starts a few minutes into the heating cycle. It seems to be coming from the section of pipe that runs from the boiler to the living room. It bangs for about 10 minutes and then you hear water gurgling in the living room radiator. As this happens you start to hear air being pushed out the vent at the end of the radiator but it starts and stops, like someone breathing. After a few more minutes it stops and everything is quiet and the living room radiator is warm. The living room has a burnham baseboard radiator. When I bought the house, the radiator didn't work at all in the living room. I found a clogged, corroded union in the pipe running out to it and replaced it. Since then it has had heat but makes noise. I have removed a section of the baseboard heater since I was told it was too long originally (it was 18 feet long, now its about 10). I've noticed it seems to heat better but no help with the noise. I have made sure the rest of the radiator is angled back towards the pipe so it drains properly. Can anyone help me with what steps to take next?

Jamie Hall

Check the runout for both pitch and straightness. You must have adequate pitch, end to end -- but also there must be no sags along the way. Particularly in older houses it's not unusual to have a sag in a long length of pipe, and that will cause exactly the problem to which you are referring.

ethicalpaul

Jamie is right as usual but I will add that those baseboard radiators are not designed for 1-pipe steam (because of this very issue I believe) and since you said the gurgling is at the radiator I think the low spot in your case is right there.

You can try to ensure that the radiator has good pitch toward the pipe side, and that the supply pipe itself has no sag (a good hiding place is right under the floor unfortunately).

But the real fix may require replacing that baseboard with a real radiator.

Hap_Hazzard

It depends on the type of baseboard. The term gets applied to a lot of different units.

If it's a fin-tube type baseboard, it will work on a one-pipe system if the pipe size is large enough relative to the EDR. I have a couple of 2" fin-tube radiators that work okay (except that they don't have enough mass to stay warm after the cycle ends).

If it's one of those cast iron baseboards with the ¾" supply fittings, or a ¾" fin-tube unit you have to run separate supply and return pipes and pitch them towards the return, and the return can't join the main return line above the water line.

ethicalpaul

He said "Burnham baseboard" so I'm picturing https://www.usboiler.net/product/baseray-baseboard-radiator.html

Hap_Hazzard

ethicalpaul said:

He said "Burnham baseboard" so I'm picturing https://www.usboiler.net/product/baseray-baseboard-radiator.html

Oh, sorry, I missed that. Yes, those can be piped as I described above. I was considering replacing one of my fin-tube radiators with one of those, but now I'm looking at one of those CastRads. Haven't priced it yet though.

wz25

We have a handful of the Burnham baseboards in our 1915 colonial. These were installed during our renovation before we knew better, and they are not piped ideally-- 3/4 copper runouts, single-pipe. The two on the first floor are about 5 and 7 feet, respectively. We have another two 4-5' on the second floor, plus a little 2' baseboard. There are five other standard radiators throughout the house (piped properly).

Before @Dave0176 re-did our near-boiler piping (and an number of other much-needed fixes), we had constant issues with the baseboards. They would heat, but were prone to spitting water out of their vents, and we would hear gurgling noises in the pipe. I found that if the boiler water was not pristine, the baseboards would be the first to react-- so I ended up having to skim every couple weeks last season. We never had any water hammer, but definitely had wet steam. Even with shims to ensure more than adequate pitch, the baseboards would kill vents-- I think I changed the vents on one baseboard twice last season.

After the work by Dave, our steam is significantly drier, and I no longer hear a sound from any of the radiators, baseboards included; no more air vent panting, nor gurgling. So, while I realize that they are not "supposed" to work (in a one-pipe configuration), they in fact do-- although you'd best have proper near-boiler piping and dry steam. I have no doubt that it would be better to pipe them as 2-pipe or swap them out for real radiators, but I'm not terribly motivated to do so now that the walls are all closed up, given their performance is quite adequate. Even the 7' baseboard will get hot all the way across if we crank the heat high enough so the thermostat doesn't shut the boiler off.

Bottom line: if you're stuck with baseboards with a single 3/4" runout, it's not the end of the world, but pretty much everything else needs to be ideal if you want them to function reliably. They are much less forgiving than standard radiators. And needless to say, I would not have installed them in the first place had I taken the time to educate myself beforehand.

nate70500

Hap_Hazzard said:

ethicalpaul said:

He said "Burnham baseboard" so I'm picturing https://www.usboiler.net/product/baseray-baseboard-radiator.html

Oh, sorry, I missed that. Yes, those can be piped as I described above. I was considering replacing one of my fin-tube radiators with one of those, but now I'm looking at one of those CastRads. Haven't priced it yet though.

Yeah that is the exact baseboard heater I have. So i need to run a separate return line from it back to the main?

nate70500

wz25 said:

We have a handful of the Burnham baseboards in our 1915 colonial. These were installed during our renovation before we knew better, and they are not piped ideally-- 3/4 copper runouts, single-pipe. The two on the first floor are about 5 and 7 feet, respectively. We have another two 4-5' on the second floor, plus a little 2' baseboard. There are five other standard radiators throughout the house (piped properly).

Before @Dave0176 re-did our near-boiler piping (and an number of other much-needed fixes), we had constant issues with the baseboards. They would heat, but were prone to spitting water out of their vents, and we would hear gurgling noises in the pipe. I found that if the boiler water was not pristine, the baseboards would be the first to react-- so I ended up having to skim every couple weeks last season. We never had any water hammer, but definitely had wet steam. Even with shims to ensure more than adequate pitch, the baseboards would kill vents-- I think I changed the vents on one baseboard twice last season.

After the work by Dave, our steam is significantly drier, and I no longer hear a sound from any of the radiators, baseboards included; no more air vent panting, nor gurgling. So, while I realize that they are not "supposed" to work (in a one-pipe configuration), they in fact do-- although you'd best have proper near-boiler piping and dry steam. I have no doubt that it would be better to pipe them as 2-pipe or swap them out for real radiators, but I'm not terribly motivated to do so now that the walls are all closed up, given their performance is quite adequate. Even the 7' baseboard will get hot all the way across if we crank the heat high enough so the thermostat doesn't shut the boiler off.

Bottom line: if you're stuck with baseboards with a single 3/4" runout, it's not the end of the world, but pretty much everything else needs to be ideal if you want them to function reliably. They are much less forgiving than standard radiators. And needless to say, I would not have installed them in the first place had I taken the time to educate myself beforehand.

Thanks for all the info! Sounds like my problem since I've replaced the vent on the baseboard 4 times in 2 years. I have already significantly pitched the baseboard rad and it made no difference. The piping near my boiler is old so I'm sure it isn't ideal. I will have to see if skimming my water makes any difference. I don't have a lot of money to spend to have someone come in and redo the piping near the boiler so it seems like the best option for me is to:
1. Go into the crawlspace and check the angle of the pipe running out to the baseboard. I'm guessing the house has settled causing the pipe to no longer be angled properly. This is the cheapest thing to start with.
2. Running a return line to the main would require digging out part of my crawlspace since there is only about 4 inches between the dirt and the floor (and of course the end of the rad is at the furthest point in the crawlspace). I think if re-pitching the line does not work, I will just buy a regular radiator for the living room. It is not a huge room so I don't think it requires more than 1 rad.

nate70500

Im also realizing with the baseboard radiator, the line that runs out to it is 1 1/4 inch but it reduces down to 3/4 right before the shut off valve so I would imagine a reduction in size like that is not helping at all, which would be why I need a return line on it

Hap_Hazzard

Based on what @wz25 said, I'd leave adding return piping as a last resort. My advice above wasn't based on first-hand knowledge; his is. Any steps you take to achieve dry steam will give you more bang for your buck, and if it gets your baseboards working, you're done, but if they continue to give you trouble, running those returns is still an option.

Bear in mind that if you do need to add returns, you can use ¾" copper, or maybe even PEX, but you should ask a pro if that's realistic.

nate70500

What are the best options to achieve drier steam?

KC_Jones

nate70500 said:

What are the best options to achieve drier steam?

That is handled at the boiler, we would need to see pictures of the boiler and piping above it to give you some insight. Pictures that show everything at once are helpful.

nate70500

I will take some later today and post them. Thank you for all the help!

Hap_Hazzard

nate70500 said:

What are the best options to achieve drier steam?

Have one of these pro's repipe your system.

Or, if you want to do it yourself, long risers, drop header, adequate venting, clean boiler water, pipe insulation, and make sure your burners haven't been cranked up. Some improvements can be done incrementally. Just start posting pictures and let us look for problems and make suggestions.

wz25

Sounds like a plan.

nate70500 said:

Im also realizing with the baseboard radiator, the line that runs out to it is 1 1/4 inch but it reduces down to 3/4 right before the shut off valve so I would imagine a reduction in size like that is not helping at all, which would be why I need a return line on it

That's excellent! That should make it much easier to get a real radiator if needed, and take advantage of that 1.25" runout. I suspect baseboards are problematic not (mainly) because of the physical configuration, but because your input is 3/4". That's over 40% less area than even 1".

Would definitely check the angle first to address the hammer, and skimming if and as needed for general maintenance. That alone might be enough-- having 1.25" up to the valve might buy you enough wiggle room to have an operational baseboard once those two items are addressed.

ethicalpaul

nate70500 said:

Yeah that is the exact baseboard heater I have. So i need to run a separate return line from it back to the main?

"need" is a stronger word that I would use. You might be OK if you can address any piping where pools are forming. I'm sympathetic because I'm going to have to re-pipe my bedroom radiator due to a low spot in the floor just below it.

nate70500

How do I go about skimming the boiler?

ChicagoCooperator

Is finding a used radiator and replacing the baseboard an option?

nate70500

ChicagoCooperator said:

Is finding a used radiator and replacing the baseboard an option?

Yeah it is what I am going to do if re-angling the line running to the baseboard and trying to make the steam drier doesn't work. It would be cheaper than having someone come look at my system and easier than running a return pipe off the end of the baseboard. I only have the 1 baseboard in my house, every other one is a stand up radiator and I have zero issues with those.

Fred

The 3/4" reducer is your bottleneck. There isn't enough room for Condensate and steam can't to share the space. Also, you made a comment above about adding a return line from the baseboard back to the "Main". Be aware, that return will have to drop into a wet return, below the boiler water line. If you return it to the Main, you will have steam entering into both ends of the baseboard.

EBEBRATT-Ed

@nate70500

Check the pitch on all you piping. You can either replace the baseboard with a radiator or fix the baseboard so it will work. Your choice. Baseboard works fine on steam if piped right.

If the base board is long I would pitch it slightly away from the steam inlet and add a 3/4 return line at the other end. Drop the return down and tie into a wet return. If you cant do that drop the return down below the steam supply main at least 2' to make a trap (water seal) then rise back up into a new tee into the supply main. Have the new tee looking down to tite into the new return

Hap_Hazzard

ethicalpaul said:

I'm sympathetic because I'm going to have to re-pipe my bedroom radiator due to a low spot in the floor just below it.

Hap's correlate of Murphy's law says that the closer a radiator is to where you sleep, the louder it bangs.

nate70500

Here are some pictures of my boiler and the surrounding piping

nate70500

So I got into the crawlspace and attempted to re pitch the pipe properly, it was almost completely horizontal. I was able to get the farthest 10 feet of the pipe sloped correctly but ran into issues with the last 8 feet in the crawlspace. I can't get it to slope properly without the end 10 feet being pitched wrong. I can't raise the end 10 feet anymore (its already against the 2x4s at the end). The section running in the basement back to the boiler is also pitched correctly. Any suggestions? The only way I see to pitch it correctly is to replace the line going to the main and have it meet the main a little lower. I do not want to do this as my main is already on the shorter side. I was thinking I could move the radiator to the closer side of my living room right were the pipe goes into the crawlspace and is already properly pitched. Is there any reason I couldn't do this?

JUGHNE

You said "2 x 4", I assume you are referring to floor joists?
If the pipe is not in the center section of the span and you have some height to the floor joists, (2 x 10's or so), it is possible to notch the bottom of the joists. You would want to angle cut the joists at angles so as to make the cuts "pigeon toed" . This is to prevent the joists from cracking in a linear direction.

Or you could make the joist into a sandwich.....3/4" plywood, lengths about 2' long, the height of the joists, then glued and screwed onto both sides of the joists. Then cut the notches as above.
This would reinforce the joist, making it a laminated beam.
Plenty of screws though.
I have done this, fair amount of work but it maintains the integrity of the structure.

You could Goolge for a Utube of this.

nate70500

> @JUGHNE said:
> You said "2 x 4", I assume you are referring to floor joists?
> If the pipe is not in the center section of the span and you have some height to the floor joists, (2 x 10's or so), it is possible to notch the bottom of the joists. You would want to angle cut the joists at angles so as to make the cuts "pigeon toed" . This is to prevent the joists from cracking in a linear direction.
>
> Or you could make the joist into a sandwich.....3/4" plywood, lengths about 2' long, the height of the joists, then glued and screwed onto both sides of the joists. Then cut the notches as above.
> This would reinforce the joist, making it a laminated beam.
> Plenty of screws though.
> I have done this, fair amount of work but it maintains the integrity of the structure.
>
> You could Goolge for a Utube of this.

So basically notch a V shape into the floor joist so I can move the pipe higher at the end closest to the radiator? And then could I reinforce the floor joist with some 2x4s? Sounds like the same thing I did in my kitchen ceiling for the shower drain so I'm familiar with the idea

JUGHNE

I would reinforce the floor before cutting.
Plywood the full height of the joists and about 2' long on each side. Just 2x4 above the notch could allow the joists to split.
The plywood sandwich would not allow that to happen.

nate70500

> @JUGHNE said:
> I would reinforce the floor before cutting.
> Plywood the full height of the joists and about 2' long on each side. Just 2x4 above the notch could allow the joists to split.
> The plywood sandwich would not allow that to happen.

Cool I'll do that thanks!

Jamie Hall

Ah... um... well... I would be seriously inclined to glue as well as screw the plywood sisters on, and extend them to the end of the joist in the near direction and at least 8 times the depth of the joist in the other, towards the centre. And if the cut is to be in the middle third lengthwise of the joist, it is not recommended at all without an engineering analysis of the remaining moment carrying and bending capacity of the beam -- even with sisters. (For reference, the moment capacity of a beam is in proportion to the width of the beam times the square of the depth; the bending stiffness is the width of the beam times the cube of the depth).

JUGHNE

Jamie, I thank you for a great dissertation on structural issues that every plumber and pipe fitter should study.....you are completely correct.
But in reality of compromise I feel just the plywood sandwich, well glued and screwed will be the most we ever see.
I am thinking his notching may be only 1 1/2" at max.
I realize the design of the notch is critical to not splintering the rest of the joist.
Hopefully the OP and others now realizes what bad notching could do to the floor.

nate70500

I could also add some supports under the floor joist. I did that to a lot of them I'm the crawlspace when I bought the house to help prevent any future shifting of the floor since it's an old house

nate70500

A friend of a friend (an experienced carpenter) came over today and we seem to have solved the problem. We basically added a second floor joist against the first one, lag bolting them together. We the notched the joists out just enough to raise the steam pipe for proper pitch. Thank you for all them suggestions and help!!!