Hunting down water hammer

wildrage

I've read all I can about water hammer and am still a little stuck. All radiators have been pitched and have new vents. Very disturbing water hammer can be hears about 7 minutes after thermostat calls for heat, and lasts for about 5-10 minutes. There are some slight pings all around the house, but the worst seems to be coming from a riser going to the 2nd floor. Sounds like it's being whacked by an aluminum baseball bat and wakes me up at night. The steam main itself doesn't seem to be making any noise, just this one riser. I have a few questions:

Some facts about my system: 1 pipe system, 110 years old. 6,000 sq foot house. Also have a condensate pump and several steam traps. I hear the pump kicking on from time to time - maybe 3 times a day, for 10 seconds at a time.

1. Could this be related to the pressure setting? I'm attaching a pic below of the pressure control. Does this mean 3.5 PSI? I've never seen the actual pressure guage register anything.
2. How much danger am I in from having the water hammer blow open one of my pipes? In the back of my head, I imagine a 100 year old pipe (if it hasn't been replaced - who knows?) getting knocked around.
3. Any pointers for hunting the cause of this down?

Thanks!

BobC

Have you checked the pipe that feeds the radiator in the cellar to make sure it's pitched so any water can find it's way back to the boiler?If water is allowed to sit in a pipe and steam comes across that water it can hammer. You could also have a short horizontal pipe under the floor near the radiator that is pitched wrong.

Bob

wildrage

Thanks for the response. I don't think this radiator is even connected to this riser. The riser comes up out of the floor on the side opposite of the radiator valve. I also don't feel any concussion on the radiator at all while it is hammering. I'm thinking that maybe it's wherever that riser meets the steam main.

On another note, can any one shed any light on what setting my pressure is set to? Is it at 3.5 (I see a smaller dial above the larger one that is confusing me). Should I try knocking it down to 1.5?

Abracadabra

That pressure control looks like a white rodgers. Do you have the cover for it? Pressure looks like its' 3.5 cutout and .75 diff for a 2.75 cutin. way too high. You need to install a new pressure gauge that measures in the 0-3 psi range. Lower the cutout to 1.5psi to start. Your hammering may be due to the high pressure, but you say that it starts 7 minutes after boiler cycle starts. Need to have a functioning pressure gauge for more help. What kind vents have you installed? With a cutout of 3.5psi and depending on the size of the riser and runout that's hammering, the pressure may be trapping condensate in the riser. What's your near boiler piping look like? Pics?

wildrage

You were right on with the brand. I dropped the pressure - maybe that will help a bit. As soon as I dropped it the condensation pumped kicked on for a few seconds. Coincidence?

JUGHNE

Yes, more pictures please. It looks like an iron pigtail for your pressure control & gauge. Have you ever cleaned the pigtail. If it is sludged up the control and gauge will never be accurate.
The gauge for sure won't tell you much, even new. You need a 0 to 3 Psi as mentioned.

wildrage

Another observation. While it is hammering, while listening to the riser, I can hear the steam pushing up and swooshing, almost in waves, like 2 seconds a part. I wish I could describe the sound better. Like a hissing pulsating sound.

Abracadabra

Not thrilled with the reducing tee in the header. Curious as to why there's a condensate pump. Got pics of that? Why is there tape all over the barometric damper? What's that connected to? Is the return from the condensate pump piped thru that 1"? copper?

BobC

Does it sound like it's panting? That could indicate standing water in a pipe.

Bob

wildrage

Sort of like a hiss or swoosh...but it's definitely cyclical, and as if there is pressure behind it. Each 'push' lasts about 2 seconds and there is maybe 1 second in between. here are some pics. The pipes to the condensate pump start across the basement (about 20 feet), run down through a trench, through the piping in the second pic, and into the condensation pump in the 3rd pic. Yes, those copper pipes are returning from the condensation pump - i'm guessing that's a bad thing?

EDIT: Sorry, the 1st pic is rotated 90 degrees CW

wildrage

PS, that damper is for a secondary coal stoker that was installed by the last home owner (totally separate forced air system). Apparently it was only run once, and I haven't run it since I purchased the home 2 months ago (since natural gas is pretty cheap right now).

Dave0176

Near boiler piping leaves a LOT to be desired. There is no way 24" of rise above the water line for that header. That boiler with that piping must be a water siphon creating water hammer in piping.

Abracadabra

wildrage said:

Sort of like a hiss or swoosh...but it's definitely cyclical, and as if there is pressure behind it. Each 'push' lasts about 2 seconds and there is maybe 1 second in between.

sounds like panting to me. check riser takeoffs from main not being pitched properly and the main after that takeoff not being pitched properly. the near boiler piping is not helping the situation. Is this something that started happening recently? was it fine before?

wildrage

I've only been in the house since late October, so I don't have a lot for reference. I know it wasn't this loud when I first started using the heating system. Oddly enough it seems to have intensified 10x after I pitched the radiators and installed new vents.

ChrisJ

The new venting is allowing the boiler to breath better.
The piping around the boiler doesn't like this and is sucking water out of the boiler.

Don't change the venting, fix the piping around the boiler.

wildrage

Thanks. I think we can all agree that this isn't the season to be changing boiler piping...but I have some more observations after digging through the drop ceiling.

So the pipes in this picture are actually going towards the boiler, but are the last on the line at the same time. This main literally goes around the entire basement (I'm thinking in the neighborhood of 50 feet of pipe if not more (its a 1500sq ft basement)), then splits - 1 goes to the radiator(left) right next to the riser, and the other is the rise(right), going up to the second floor. Looks like a hatch was cut at some point, presumably a radiator pipe repair.

Does this help with the analysis any better? Or am I still where I left off?

PS. Excuse my unsightly asbestos.

ChrisJ

Where does that drain to?

Fred

You have to focus on the area where you hear the banging and the sloshing. That's where the water is sitting. Is the noise at that "Y" ? Is that Main with the "Y" in it pitched towards the dry return end or in a direction opposite the pitch of the rest of the main?
As been said, the header over the boiler needs to be raised up, in the Spring when the weather breaks. While your doing that, also take that reducer out of it. That Header is also holding water because of that reducer.

wildrage

I'm going to have to play some more drop ceiling bingo, but my guess is that it goes back around the basement through that 50 feet of pipe, back to the boiler, hopefully pitched decently. There is a steam trap/hoffman condensate unit that intercepts about 15 feet from the boiler. This is the end of the line, and the absolutely furthest pipe from the boiler - so far away that it basically circles back, and is only 5 feet from the boiler.

I have to double check with a level, but the pipe appears to be pitched 'down hill' from that Y. The noise is definitely coming from the right pipe in that Y going up to the riser. I can literally put my ear on the radiator (the left pipe of the Y) while the riser is banging away, and hear absolutely nothing. I thought about the possibility of the radiator above the riser causing the banging, and resonating down, but on the 2nd floor, the noise is barely noticeable. The banging is most pronounced on the lower 1/3 of the riser, going from the floor to ceiling of the 2nd floor.

Jamie Hall

Make sure that right hand pipe is pitched strongly back to the main -- the one that keeps on going around -- and that the main pitches on strongly away from that Y, whichever way it goes. That set up -- with a horizontal Y takeoff like that -- is an almost ideal example of how to pipe to create hammer! Unless things are pitched like mad, whango.

Fred

My guess is that "Y" is problematic. Steam is headed from the main, at the top of your picture (Where there is no insulation) into both of those legs in the "Y". Condensate is trying to return from the riser/radiator on the right leg of that "Y' and colliding with the steam. That section of pipe and/or the "Y" has to be pitched into the flow of steam. From what you have said, I assume you have a parallel flow system that loops around the basement and returns to the boiler. It would appear, the water has to make an ackward turn to follow the pitch of the rest of the main/dry return but I don't see where the main continues past the end of that left leg??? If that's the case, either that "Y" needs to be removed and the run-out to the riser take off at a 90 degree or that Right leg of the "Y" needs to be pitched down towards the riser end and a drip leg installed at the elbow where it turns up, essentially replacing the elbow with a Tee so that the return water can drop into the drip leg. If you use a drip leg, that has to tie into a wet return below the boiler water line.
More pictures of that area and how the main runs would certainly be helpful.

Abracadabra

What size vents have you installed on the radiators?

wildrage

They are all pretty small. I did notice that the radiator (that comes up on that other side of the Y) seems to be pushing air out like crazy when the furnace begins to cycle. Do you think a larger vent may help my situation? To give some context, this radiator is on the first floor. It is a 3 story house with approximately 15 radiators in the system.

Abracadabra

wildrage said:

They are all pretty small. I did notice that the radiator (that comes up on that other side of the Y) seems to be pushing air out like crazy when the furnace begins to cycle. Do you think a larger vent may help my situation? To give some context, this radiator is on the first floor. It is a 3 story house with approximately 15 radiators in the system.

Small? Do you mean slow? how slow? Pic? Model? #? You don't want a faster radiator vent in this situation.

wildrage

It has a Durst #40M...very small pin-hole sized opening Durst #40M

Last night, for sharts and giggles, i replaced it with a larger Maid o Mist (#C). I observed it spitting water while the steam hammer was occurring - in harmony with the hammer.

Jamie Hall

wildrage said:

It has a Durst #40M...very small pin-hole sized opening Durst #40M

Last night, for sharts and giggles, i replaced it with a larger Maid o Mist (#C). I observed it spitting water while the steam hammer was occurring - in harmony with the hammer.

Not really surprised... nice to know that that particular bit of piping may be the problem. It would be nice to really repipe it properly, but I couldn't tell from the pictures whether you had enough head room there.

wildrage

There is a bunch of room, but def a project for the spring. Just trying to think of ways to quell it a bit until then. Was just looking at the radiator that's on the other side of the Y on the pipe, and the pitch is extremely minimal, if anything. Could it help pitching it a bit better?

BobC

Anything you can do to get a bit more pitch might help but make sure it doesn't harm the pitch elsewhere. Come spring you can get someone in there to correct the piping.

Bob

nicholas bonham-carter

Probably the condensate pump was put on to as a bandaid to compensate for the large amount of water thrown up by the improper piping.
Massive main venting, with slower rad venting would at least reduce the amount of water rising up from the mains to the radiators.--NBC

wildrage

Thanks - I sort of suspected that. Others have commented that my one pipe system really shouldn't need a condensate pump.

I know for a fact that I have little to no main venting. With well over 50ft of main, I know that definitely needs to be addressed. I've been searching for a local supplier of main vents and have come up with nothing. Any suggestions for online suppliers?

nicholas bonham-carter

Supply house.com has been my choice for Goton #2's. You may need a couple of them at least if the dry return is 50 feet long.
In your case especially, you want a very low resistance to the air escaping out of the dry returns, and a somewhat higher resistance to the air leaving the aviators. This hopefully will keep the excess water in the mains, to be drained into the wet return/condensate tank.
I wonder if there is any restriction in that trap, causing water to back up. That would be another reason to get rid of the trap, tank, and pump.
The 0-3 psi gauge comes from Valworx, and later when you have all these problems sorted out, you will be able to use a 0-15 Ounce gauge, and vaporstat!--NBC

wildrage

nicholas bonham-carter said:

Supply house.com has been my choice for Goton #2's. You may need a couple of them at least if the dry return is 50 feet long.
In your case especially, you want a very low resistance to the air escaping out of the dry returns, and a somewhat higher resistance to the air leaving the aviators. This hopefully will keep the excess water in the mains, to be drained into the wet return/condensate tank.
I wonder if there is any restriction in that trap, causing water to back up. That would be another reason to get rid of the trap, tank, and pump.
The 0-3 psi gauge comes from Valworx, and later when you have all these problems sorted out, you will be able to use a 0-15 Ounce gauge, and vaporstat!--NBC

Thanks! And I'm within the range for their FastTrack shipping, so I should get it by tomorrow!

wildrage

Thanks for all your help guys. I just examined every foot of steam main in my basement (must be atleast 100-150ft), and only could find 1 vent. I looked for plugs, or anything that looked like it could support a vent, and found nothing else.

Worse yet, the vent is on the condensate return. Does this even do anything? Is it even worth replacing with a Gorton#2?

Also, are there any areas I should re-examine? Where are these typically installed? I did a pretty thorough exam, but it's worth checking again.

Jim

wildrage

Hope everyone had a great holiday. I made a few new observations on my system.

1. Steam is shooting and spitting out of the radiator on that same Y pipe split. There is even a little bit of steam spitting out of the shut-off valve.

2. The fitting right before the Y is going to need to be replaced. When the system is running, approximate 1 drip occurs every 30secs to 1 min.

What could be causing the vent to not close, and continually spew steam? I've tried 2 different vents (1 larger, and one smaller), and seem to have the same result.

Almost seems like there is too much pressure, and steam is trying to escape anyway it can. The pressure in the system has been turned down to 1.5.

Any thoughts?

BobC

That gauge may be lying to you, try another one to be sure - I would just add a 0-3PSI gauge onto the pigtail along with the pressuretrol.

Bob

Steamhead

Another possibility is that the F&T trap near the Y where the banging is, has failed closed or partially closed. This would let water back up into the steam piping, causing banging.

You need to get rid of the condensate pump and the traps, add the proper main vents, restore the return piping to its original state, fix the leak and repipe the boiler header.

This is a job for a Steam Man. Where are you located?

wildrage

I'm in NE PA, 17901 (Pottsville). About 120 miles due west of NYC on the 78 corridor or 80 miles NW of Philly.

Can't seen to find any good recommendations for my area, although I know there must be a ton of steam systems in operation around me.

wildrage

I also just got shocked by the pressuretrol. I'm assuming that's not normal. Sigh.

Steamhead

You might have touched a live terminal. Turn the power off before opening the pressuretrol cover.

I've actually driven thru Pottsville on US 209. It's roughly a 3 to 3-1/2 hour drive from Baltimore. If you can't find anyone closer, let me know.

wildrage

Thanks. Might be worth it to me just to get someone who can be trusted. I'll message you privately later.

nicholas bonham-carter

You would have the best eyes on this with Steamhead.--NBC