water hammer plus gushing alot of water out of main vent plus slow steam

iopcool20 · March 2017

Sorry to disturb the internet folks but here is my story for this season. I have two family residence with one pipe steam boiler (peerless) with about 18 rads. Boiler is few years old (less than 5) Had a second floor room poorly insulated and was losing heat fast. My thought was to seal air leaks in room and send more heat to room or at least enough as well. I changed all radiator air vents added a few TRVs and changed two vents on the mains as well. This system was above boiler return pipe. Two vents replaced on main are one no45 (bullet shaped) and the other a groton no1. Also added a purge valve near the hartford loop for the return since there was none. Also on 2nd floor problem room took that rad and swapped with rad in another room. they are almost same size but one is newer and one is older type. Thought would make a difference.

On to the issues in order of severity. First water gushing out of the main vent at the end of the line (the groton 1). Gushing water is alot and spills on floor and goes across the floor to give you an idea of how much water it is. Usually or I have noticed at beginning of cycle accompanied with the water hammer. Water hammer happens at beginning of the cycle and last no more than 10 -15 minutes. I have notice boiling water heading up to the 2nd floor and two days ago i thought when I swapped the rads maybe that pipe fell causing a wrong tilt on the return so I checked that and one rad was full with water, too much water. Lastly the steam does get to all radiators but some faster than others and in initial start it takes quite a while to heat at least the steam valve before the rads. I also have an automatic feed that turns on daily (obviously because water isnt returning to boiler) I never had the hammer going on before I started to touch things. The hammer started once I put an addition trv on a rad and swapped the two rads. Need a little bit of guidance this is fueled by oil and it burns alot of oil. because of long cycles to get the heat up. I have noticed I have wet steam because water at some of the air vents at different times. I added the purge valve to the return 1 day ago and during that time drain the boiler completely and the water hammer and gushing main vent (could be a return vent pipe size 1 inch) is back very fast.

Other info main steam pipe are 2 inch circumference and return is 1 inch pipe.
one pipe system with return right below the steam main with a slight pitch.
auto feeder feeds daily
site glass is usually half or 3/4 full or higher. I drain a bit of the water whenever I see this to half.

Any advice is appreciated all work described done by myself.

BobC · March 2017

It sounds like the boiler is gaining water try shutting off the valve that feeds the autofeeder (if you have one), the valve in the autofeeder might be leaking by. Set the autofeeder to delay feeding water if you can. If you feed manually that valve might also be leaking by. If the pipes before and after a valve are cold that valve is flowing water. Find and fix any leaks and make sure the wet returns are free and clear so water can get back to the boiler quickly.

Make sure all horizontal pipes are sloped so water can find it's way back to the boiler and make sure there are no dips that might cause water to pool.

What pressure is the boiler running at, it sb 2psi or less. Has the pigtail been cleaned recently? They get plugged and then the pressuretrol can't see whats going on inside the boiler.

If the sight glass is bouncing around a lot or shows signs of oil the boiler needs to be skimmed to get rid of the crud - draining water won't work.

Buy the "Lost Art of Steam Heating" it's for sale on this site and at Amazon.com

Bob

Danny Scully · March 2017

As always, what is your location and please post pictures.

Paul48 · March 2017

In your description, you fail to mention boiler pressure or what is going on at the boiler. You say you replaced radiator vents....from what, with what? What TRV's? Do they contain a vacuum breaker? Not all come with them.

Jamie Hall · March 2017

Are the TRVs on the radiator vents? They should be. If they are on the radiator inlets, they are going to cause a lot of trouble -- the inlet valves to the radiators on a single pipe steam system must be fully open all the time.

The water gushing out of the main vent and the water hammer on startup both suggest that the near boiler piping -- the risers and header -- may be suspect. Would you post a picture or pictures showing the near boiler piping?

Problem is, you have several unrelated problems, and it's going to take a bit of sleuthing to get them sorted out and fixed.

And as @Danny Scully said -- where are you? We may know someone in your area who could help you out.

iopcool20 · March 2017

Im in ny queens, so pressure starts at 1 and goes up to around 3-4 once system has been running for while. TRVs are installed where the rad air vents are and they have the vacuum breaker as well. I changed all air vents on all rads since this is my second winter in house and all these look years old and boiler is less than 3 years old. I got different size vents D, C, 5s. All rads are pitched properly. I will shut the valve at the auto feeder, maybe even kill the electric to it as well. Mine is the universal type with 4 dip switches not much adjustment. I dont think I have any wet returns all piping are above boiler except hartford piping. Dry return might be clogged Im thinking or water isnt getting to boiler. I plan to open the return today and see how much water is in there. also once I turn the auto feeder I feel that might stop the excess water in system. Could be a leak or faulty feeder idk.

tonight will open return see how much water comes out and attempt to get water from one end to the other. To discount blockage. I know dry return is rarely blocked but I did change a few rad valves by cutting and such so maybe something jumped in when I wasnt looking.

I will take pictures tonight of mains and return.

Well pressurtol wasnt checked boiler isnt more than 4 years old, ill find the book and find the exact date of boiler , so would it get clogged so fast?

Also one observation when I added the purge valve on the hartford loop the inside of the pipe had alot of gunch black and orange color in little balls on the wall of the pipe. It wasn't hard but very soft I could move it easily.

@ Paul I changed the old vents out just for maintenance and to insure they were working. I put mostly 5s and D on large rads and upstairs cold room. (Missed one on the main thats near some old asbestos wrap I dont want to go near, its ancient looking)

@ Jamie all valves are open

unrelated question I have a long radiator with valve leaking even after i repacked it. I would change it but its in hard to reach location Ill take picture, what question is what type of wrench can give me reach behind the radiator where I can only reach my arm in??

gtg call the oil man we have a snow coming tonight cheers guys.

BobC · March 2017

If the system is really going up to 4 PSI that is much too high, 2PSI is the maximum and hopefully less. Be warned 0-30 PSI gauges are not that accurate at the low end of the scale.

The boiler might be fairly new but the system isn't, all the stuff shaken loose in the pipes ends up in the boiler. How many steam mains do you have? You want to vent the mains as fast as possible and much slower on the radiators. Replacing an old slow vent on the mains will save fuel and make the system better behaved.

Bob

iopcool20 · March 2017

Two steam mains, Quetstion is the No 45 vent the correct vent size for the main? thats is what was on there and hence I replaced with same type. see my old picture of origin

Jamie Hall · March 2017

That vent is too small by modern standards. How long and what diameter is that main?

To echo the comments on pressure -- don't bother to change any more vents until you get the pressure under control. That much pressure almost certainly will damage the new vents.

iopcool20 · March 2017

Ill take pressuretrol off and see if its clogged tonight as well.

iopcool20 · March 2017

that main is 2 inch circumference pipe and that vent is piped off of the 2 inch pipe to 1 inch then the vent. Pictures to come tonight

iopcool20 · March 2017

sorry pressure on trol set to .05/1 lowest setting

iopcool20 · March 2017

Good morning last night I checked the presuretol which wasnt clogged and very clean actually. Next I turned off the auto feeder. After that the steam seemed to heat much faster and no more water hammer and no gushing main vent last night. I presume the auto feeder was not only filling the boiler but flooding the return line as well. Also the pressure gauge read 1-2 psi throughout all cycles. There has defiantly been a difference in time the rads actual got hot and also they dont seem to be heating extremely hot as before but more evenly throughout the whole house. Thanks for eveyone on the forum. I still have to figure out if I will either replace the auto feeder or leave it turned off. ( it wasnt leaking water pass its valve either) The auto feeder is the simple William and Donnell. I will attach pictures

iopcool20 · March 2017

correction this morning before end of cycle psi was up to 3

KC_Jones · March 2017

That boiler isn't piped correctly. If you have a manual you can look up the proper piping.

nicholas bonham-carter · March 2017

The vents can be damaged by pressure above 3 psi. High pressure plus wet steam from the incorrect piping makes for very ineffi$ient and uncomfortable heating.--NBC

Abracadabra · March 2017

You need to confirm that the gauge returns to zero when the boiler is off. Also install a lower pressure 0-15 or 0-30 oz gauge.
And as has been stated, the boiler is incorrectly piped which contributes to your wet steam/water hammer/water out of the vents problem.

iopcool20 · March 2017

ok reading manual now, gauge does return to zero when boiler turns off.

nicholas bonham-carter · March 2017

It looks like the LWCO has been mounted too high, and that could be a contributing factor in the overfilling.--NBC

Fred · March 2017

nicholas bonham-carter said:
It looks like the LWCO has been mounted too high, and that could be a contributing factor in the overfilling.--NBC

@nicholas bonham-carter , you're right. That LWCO is mounted way to high. It should be mounted with a nipple straight out of that Tee behind the sight glass.

iopcool20 · March 2017

Ok I see from the manuals the tees are suppose
To turn to the left not up as in my case. Can I get away with turning my bottom and top tee left 90 degrees left and removing the bottom 90 degree elbow ?

Fred · March 2017

iopcool20 said:
Ok I see from the manuals the tees are suppose

To turn to the left not up as in my case. Can I get away with turning my bottom and top tee left 90 degrees left and removing the bottom 90 degree elbow ?

Yes, that's what you need to do but remove the glass protectors (rods) and the gauge glass first. You may also need a longer vent pipe (brass pipe out of the top of the LWCO). Measure where it will hit when you drop the LWCO. If your lucky, that vent pipe may be long enough when you turn both tee's or it may need to be cut a little shorter.

iopcool20 · March 2017

Thanks where do I buy a longer brass tube for the lwco if I need it does plumbing supply carry those? I didnt see on supplyhouse.

Fyi boiler was installed in 2013 and the pressure seems to get to 3 psi daily and boiler is cutting off fast sometimes less than 10 minutes then once pressure goes down it starts up again. Ill take apart lwco and sight glass tonight and see if it reaches or if I need to purchase two tube.

Fred · March 2017

Most local plumbing houses will have that tube and, if you call Supplyhouse.com and tell them you need the vent tube for a McDonnell Miller #67 LWCO, I'm sure they have them.
As to pressure, 3 PSI is too high. Make sure the white wheel inside the Pressuretrol is set to "1" (facing front of unit). Also, make sure the pigtail that the Pressuretrol is mounted on is not clogged and that you have good venting on the mains.

iopcool20 · March 2017

I checked the pressure control tubing its clean and clear, the outside of the control is set to 0.5-1 ill check inside white wheel wheel tonight. The mains have three vents two number 1s and 1 old original vent I have no idea what size. (cant change it, right next to asbestos wrap). Think I need more venting???

Fred · March 2017

How long is each main and what diameter pipe? I would guess you do need more main venting, especially that original vent. Why can't you change it? Being next to asbestos wrap isn't an issue. It's not like you work in an asbestos mill,

and you can't just ignore that vent. If it isn't even working, it's a problem. If you are really that concerned, Wrap the asbestos in plastic while you change that vent. Gorton #1's aren't very fast vents either but let's see the size of those mains.

iopcool20 · March 2017

mains are 2-1/2 in size length not sure one is at least 13 feet and other is 25 feet long. I have to measure to get exact lengths (maybe tonight). What would a good size for main vents be?

Fred · March 2017

Two Gorton 1's on the 13 ft main is fine. The 25 ft. main would benefit from a Gorton #2

iopcool20 · March 2017

Actually its the other way around the 13 foot main has one maid of mist(new) number one vent. And the longer main has two vents a groton number one(new) and the older vent.

iopcool20 · March 2017

whats a good placement of an additional vent on a longest main run?

Fred · March 2017

Switch them and put the two Gorton #1's on the 13 ft. Main and put a Gorton #2 on the 25 ft. main.

iopcool20 · March 2017

Ok thanks Ill update tomorrow.

iopcool20 · March 2017

Finished moving the lwco down to correct position level with lower tee for the sight glass. Was able to use all current piping to get it done although I had to remove all pipes on all front ports to turn the lwco. When removing the pressure gauge pipe I found pieces of debris in the pipe(see picture). The auto feeder hasnt started since moving the lwco down. Also the heat seems to be moving faster to radiators (just heated up to temperature in one cycle) Overall since the return isnt flooding anymore heat has been fast and thats a good thing. I ordered the number 2 vent for the longest main waiting for that. I really appreciate the help Thanks and have a good day.

Fred · March 2017

Those 1/4" pipes and pigtails to the Pressuretrol, gauges will gather junk. It's important to clean them out annually. Glad you were able to get the LWCO to the right location. They are on a system to detect a "Low Water" condition, not to maintain the water at the correct level, which appears to be what someone thought when they mounted it up high.

iopcool20 · March 2017

Installed the number two vent on the longest main. For this system I thing I only need to change oil tank filter when I have a chance.

This forum has been so helpful I think I'll look to maintain my other three furnaces in my rental as well thanks

water hammer plus gushing alot of water out of main vent plus slow steam

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