Banging Radiators

diy_ny

Hello,

My steam boiler was cleaned out back in November because I had banging in 2 of my radiators on the 1st floor on the opposite side of the boiler (Kitchen and Living Room). After the cleanout, the steam heat was perfect with no noises or banging and proper heat throughout the house for 4 months straight. A few days ago, now I'm starting to hear loud hammering on the same 2 radiators and I also have no heat on the second floor on that side as well. Maybe it helps to tell you that 2 of the radiators have a crappy home depot "Hoffman like" air valve. The other is an actual Hoffman #40. These 2 radiators branch off before the end of the main. Also, back in November, the main vent Gorton #1 was put as high as it could go. The sight glass always shows with clean water in the middle.

One other thing, if I drain some water from the boiler, the automatic water feeder comes on the next cycle or so as I hear it for a few seconds. I used to hear it come on like once every few weeks. Now it's almost once a day and concerned about having fresh water being put into the system. Also, the wet return is original from 1947 and I'm not sure if that's clogged or not.

Any thoughts?

Thanks.

Lard

Check for clogged pigtails (could cause a sudden change like this). Also check the pressuretrol settings while you are at it. 0.5/1 is the happy spot. A leaking auto feeder can also overfill the boiler slowly and cause wet steam to barf into the system.

Radiator pitch is also extremely important. There must be a slight slope towards the shutoff valve. The valve must never be closed or left “throttled” as this will cause hammer too.

Pictures of the boiler and the pipes around it are extremely helpful to reveal any obvious issues with the installation. Even the smallest nuances will be picked up here!

diy_ny

The radiators are pitched with a shim on the side directly under the air valve. The air valves are non-adjustable. The radiator valves are all completely open. The pressuretrol has been set to main: 1.5 and the diff is 1.5. I noticed in the past if I set the pressuretrol to .5 (I don't remember which setting but the boiler would never kick on). How can I check if I have a leaking auto feeder? Also, how can I remove the pig tail because the pressure gauge and the lwco would get in the way. Do I need to shut off power switch to the boiler and disconnect the cables and remove the pressurerol from the brass nut at the bottom which is connected to the top of the pigtail?

Fred

If the auto feed is leaking, when the boiler is idle, the water level in the boiler sight glass will be higher that it originally was and continue to climb over time. Is that the case? If not, then the auto feed is probably fine.
It is possible the return is partially clogged and water is slow to return to the boiler. If possible, you need to flush any wet returns (those below the boiler waterline) out to restore proper flow.

If the water level stays stable and you see no obvious signs of water on the floors and no leaks at the radiators and/or valves, it is possible the boiler has a leak/hole in it above the boiler water line and steam is going up the chimney, when the boiler is running. Check and see if a cloud of steam is coming out of the chimney the next time the boiler is running. If you don't see steam, you can shut the boiler down, let it cool, over fill it and see if water runs out onto the floor. If so, the boiler is probably shot.

To the pigtail/Pressuretrol, it is very possible that the pigtail is clogged and the Pressuretrol can't do its job. Yes, you will need to shut the power to the boiler off and disconnect the two wires to the Pressuretrol to remove it. Is the pigtail brass or steel? Steel ones clog faster but, given what you are saying about how the Pressuretrol is installed, it likely has never been cleaned. You may need to buy a new pigtail (a Brass one) cut the old one to allow you to turn the stub out of the boiler and add a couple nipples and a union when installing the new one so you can turn things to clean it in the future.

diy_ny

Thanks Fred. This boiler was put in early last year with a new chimney liner. I did not see any white cloud of steam coming out of the chimney while the boiler was running. I did not see any obvious signs of water leaking onto the floor. The water level is stable at the same line in the glass as it always have been. So I have not seen it going above the normal water level line. I have seen some droplets of water coming out of the living room radiator valve. When I took it out, some water came out, maybe that should be replaced? My wet return line has a gate valve and then when I opened it, it was like chocolate milk that came out for a bit but it was flowing at a fast rate so I'm not sure. I'm wondering if I should get the whole wet return line replaced?

I have a brass pigtail. Is there anyway of preserving the same brass pigtail and cleaning it out rather than bending it since it's only a year old? I did hear about using a 1/4" brass nipple with a1/4" brass union to connect to the brass pigtail. Sounds like a good idea.

Fred

Post a picture of the pigtail and let's see if it can be turned in some way to clear the LWCO and pressure gauge.
If the water level is not going up, in the sight glass, then water may be leaking somewhere or the auto feed wouldn't come on daily. Has this boiler, been skimmed? If it's only a year old it may need a good skimming to remove the oils off of the surface of the water. If there are oils on the water, it can make it hard for steam bubbles to break through the surface and that can cause water to be pushed back into the wet returns causing the LWCO to think the water level is low. Once the boiler stops on a perceived low water situation, the water rushes back into the boiler and the boiler fires again with little to no water being added.
When the boiler is running, does the water in the sight glass bounce a lot? Is there any condensate on the top half of the sight glass? Both of those situations are indications the boiler needs to be skimmed.

diy_ny

The skimming was done in Novemeber with a can of squick. Yes, the water bounces a little especially on the first 2 cycles and then empties out which then the lwco comes on and fills to the normal water line. I believe there is condensate dripping from the top to the bottom of the glass. Would another skimming fix the banging in the 2 radiators? I will upload pictures soon of the pigtail. Thanks.

diy_ny

I just uploaded the pressuretrol with the brass pigtail. I'm sure I can remove the pressure gauge.

Fred

You should be able to take the cover off of the LWCO and take the screws out that mounts it to the boiler. As long as you don't take the probe out of the boiler you don't need to drain the water out of the boiler. Once you have the mounting screws out of the LWCO, you can take the pressure gauge off as well. It is above the boiler water line also so you don't need to drain the boiler. Once that's done turn your pigtail off and take the Pressuretrol off. Clean the pigtail and buy a nipple and union that will allow the Pressuretrol to extend out to clear the LWCO and gauge so you can take it off for future cleanings.

Having said that, if you still have Squick in the boiler, drain and flush the boiler. Squick, by itself will cause foaming and unstable water. Refill the boiler and skim it again. It usually takes a few long skims to get all the oils out of the boiler and Squick will only encapsulate the oil and carry it to the bottom of the boiler. After a while the oil will float to the surface of the water again. The fact that water pushes out of the boiler is also an indicator that there is oil in there.
Yes, Squick and oil can cause all kinds of strange things to happen in a steam system, including wet steam and banging.

I might also ask, is this a Burnham Boiler? They are super sensitive to oils. I know, I have one.

BobC

If you see drops of water in the sight glass the boiler needs skimming, listen to what @Fred said and empty and fill that boiler a couple of times (do this when the boiler is cold or just warm) to get all the squick out. Then run the boiler up to steam to get the oxygen out of the water.

Next comes the skimming, raise the water level slowly till water slowly trickles out of the skim port. You want to float any oils out of the skim port so it's important the surface of the water in the boiler is still. It should take a couple of hours to fill a 5 gallon bucket when skimming.

Bob

JohnNY

The pressure reading on the gauge looks high.

diy_ny

Thanks Fred and Bob C for the skimming process. Yes @Fred I have a New Yorker. About the pigtail removal, after removing the screws and the lwco enclosure, do I remove the pressuretrol from the top of that pigtail or do I spin it out of the bushing in the boiler from the bottom? @JohnNY good catch I did notice that pressure gauge reading to be a bit high. Maybe that needs to be cleaned as well or replaced?

JohnNY

diy_ny said:

@JohnNY good catch I did notice that pressure gauge reading to be a bit high. Maybe that needs to be cleaned as well or replaced?

Screw it out of the boiler and see if the needle falls down to zero. If not, then yes, replace it. But if it doesn't, then I'm thinking the elevated pressure reading is related to the issues you're having. You may need some on-site assistance.

Fred

@DIY_Guy , If you can get the Pressuretrol off first, then do that and blow into the pigtail. You may be able to blow crud out of it and into the boiler. If you can't take the Pressuretrol off first or clear the pigtail, then spin the pigtail off with the Prerssuretrol still mounted on it. Then take the Pressuretrol off and clean the pigtail.

Danny Scully

Where in NY are you located @diy_ny?