radiators hissing from vents, one valve shooting water

CapZ

Hello all. I'm trying to help out a neighbor. The vents on 4 of her 5 radiators are hissing very loudly. One valve at the base of one is actually shooting water up near the valve handle. Aside from verifying the pipes are seemingly sloped correctly, I'm not sure where else to look. Its a one pipe system. Here's a couple pics. Hopefully someone can give me hints before I find a steam guy. One more clue is the psi rises slowly to 5 before the pressuretrol cuts out. Thanks

STEAM DOCTOR

Hissing

Sounds like there are two separate issues. The hissing from the air vents might be due to undersized radiator air vents or lack of main air vents. Also might be result of steam leaking out of air vents. Put a tissue on air vent hole and see if tissue gets wet. Be careful. Steam is hot! The leak that you are seeing by the radiator shutoff valve is a localized issue. The nut near the handle probably needs to be sealed/repacked. Usually not a big job.



Can you retake pics from further back? We need to see the piping on top of the boiler.

STEAM DOCTOR

Hoffman

The green air vent on top of the main (near the boiler) is an older version of the Hoffman 75. Base on age and the signs of leaks(brown marks) it might be time for a replacement.

BobC

Pressure too high?

Try tightening the bonnet nut right below the radiator valve handle, if that does not work you may need to replace the valve packing.



Do you know if the pressure has always been this high? Is the pressuretrol adjusted down as far as you can? It should be set for 0.5 on the main and 1 on the white wheel inside the front cover and that should turn the boiler off at 1.5 PSI. It's possible the pigtail under the pressuretrol is blocked or that the pressuretrol just is not calibrated.The gauge could be flaky also but if all the air valves are hissing loudly it sounds like the pressure os too high.



What kind of radiator air vents does she have?



Give us more pictures from further back.



Bob

CapZ

new pic

Here you go. Hope this helps. I added the main vent at the end of the end of the main thinking it would solve the problem. Previously this was plugged and NO main vents were present. Its old but was working fine on my system.

CapZ

pressuretrol

The front dial is set just under 1 and the inside white dial is at 1

Jamie Hall

With those pressuretrol settings

the boiler should cutout at not over 2 psi -- not 5 psi.  Check that the pigtail and pressuretrol openings are clear.

CapZ

pressuretrol

I cleaned out the pigtail and the fitting going to the gauge. I did not flush the pressuretrol at all. I just put it back on. I'm unfamiliar with the function of the pressuretrol. Is it just a safety cutout or does it actually regulate the boiler pressure?

BobC

Regulates

The pressuretrol regulates the maximum pressure the boiler can reach, on most systems you would like to keep the pressure under 1.5PSI.



If you turn a pressuretrol upside down and look into the base of the brass fitting you will see a very small hole that has to be clear. Unfortunately pressuretrols are often poorly calibrated, if you examine the insides carefully you will see there is a very small set screw that lets you adjust the lever between the pressure diaphragm and tension spring. If you turn that set screw just a little bit you can adjust the pressure at which it trips - by small I mean 1/16 of a turn on that 0.05" setscrew.



Bob

CapZ

Pressuretrol clear

I removed and checked the Pressuretrol and it seems to be working correctly. The boiler cuts out when it should. I added a brand new main vent, Hoffman 74 to replace the old one. With the boiler running for awhile and the Pressuretrol up to 5 +1, the boiler is staying at about 3.5 psi. The hissing is still present. The boiler pressure is still rising to the point the Pressuretrol shuts it down, but way before the radiators have time to heat the house. All the radiator vents are Gorton non adjustable. What else could account for boiler over pressure? Could a blocked exhaust cause the water to get too hot and possibly boil?

Fred

Pressuretrol and Hoffman Vent

The water has to boil to create steam.  

If you have the Pressuretrol set at .5 psi on the front of the unit and the white dial set at 1, the pressure should not go beyond 1.5psi, maybe 2psi at the very most. 3.5 is still way to high and I would say the Pressuretrol needs to be calibrated. To do so, follow these directions:

Inside the Pressuretrol, right below the micro switch, there is a pivot arm. At the end of that arm you will see a screw pin that is activated by the diaphragm at the bottom of the Pressuretrol. If you look very carefully at that screw pin, you will see it actually has a tiny (I mean tiny) hex head on it. It takes a .050 hex wrench and you can turn it clockwise (Towards the bottom of the Pressuretrol to decrease the Cut-out pressure or counter clockwise to increase the cut-out pressure (which none of us want to do but who knows, your Pressuretrol may be really screwed up!). Turn the power to the unit off first. You may find the first attempt to turn that screw a little bit stubborn (relatively speaking) because it has some Locktite on it but it does turn. Don't turn too much, a tiny fraction of a turn goes a long way towards getting it adjusted where you want it (maybe 1/32 inch turn to start with) . You may need to play with it to get it exactly where you want cut out to be.

The other issue is if you put a Hoffman #74 vent on the main, that won't work. It should be a Hoffman #75. The 74 is for a steam heater unit with an operating pressure of up to35psi. The #75 is a Steam Main vent.

I also notice an auto water feeder on that boiler. How high is the water level in the sight glass? Is it over filled? It should be no more than 2/3's to 3/4 of the way up the sight glass.  If so, it may be that the boiler is being flooded by the water feeder, thinking there is a low water condition. If it's not overfilled Is there a lot of bounce in the water in the sight glass (more than 1/2 inch to max 1 inch? If that's the case, the boiler probably needs to be skimmed.

There are some near boiler piping issues that one can see but the homeowner will need to deal with that when the weather breaks. It doesn't look like there is a Hartford loop and no swing joints on the header which adds a lot of thermal stress on the boiler and I'm not even sure there is a header there. Hard to tell from the pic.

CapZ

Main vent etc.

Thanks Fred lots of useful info there. Regarding the Pressuretrol, I took it out of the equation by turning it way up , so as to see how the system behaves when it has been running for awhile. When I lower it to the proper 0.5 +1, it cuts out before steam even reaches the radiators. So that's working fine. The other issues need to be addressed. When running there is 1/2" or so bounce in the glass. It's initially clear when off then quickly turns brown. So it clearly needs a skimming/flush. It is properly set at 3/4 but lowers often.

I ordered a #75 vent. I'm curious why the 74 wont work though. Lack of the Hartford loop was brought up by a plumber who looked at it briefly, hopefully that can be addressed. There is a header top right in the shadows. I'll get a picture of that tomorrow. It branches left to a main for 4 radiators and right to a main for 1 radiator. As I stated earlier. Neither one of these mains had vents. There is a manual valve on the pipe going to the single radiator. Not really sure of its function but there is water hammer there. Picture of that tomorrow also. Thanks again Fred, I think I'm a few steps closer to the answer.

Steamhead

How long are those steam mains

and what pipe diameter? If you're not sure of the latter, just measure the outside diameter- pipes are designated by inside diameter but we can tell this from the outside diameter.



This info will help us make sure your main vents are properly sized.



Also, please post a better pic of the steam piping directly above the boiler. It doesn't look right, but we would like a better view before getting more specific. This piping is crucial to proper steam production.

CapZ

mains and header

Here are more pictures. I'm not sure how to distinguish the mains from the header (if there is one).

CapZ

mains

The 2nd picture shows the riser up to one main, going to a single radiator. The mystery valve on that line is shown in the last pic. The first picture shows the area above the boiler which then goes left to the lines to the other radiators, 3rd picture

CapZ

mains?

Question: in the 3rd pic, are the lines that extend to the walls then 90 degrees up, are they all considered mains or just pipes leading to radiators? If its the latter it looks like there is no header

Fred

Back to basics

OK, Let's take a few steps back and get some basic questions answered. Is this a new problem or one that has existed since this boiler was installed? If it is relatively new, think back to when it began and tell us what changed around that time (plumbing, thermostat anything).

My suspicion is that this system has been a problem for a long time. There really is no header above the boiler. The Main that takes off at the right side of the riser (the pipe going up from the boiler is the riser) should be on the other side of the riser, somewhere before the equalizer (the pipe that goes down from the left side of the riser to the floor is the equalizer). There should be a header , a horizontal pipe, at least one size larger than the riser attached to the riser and your Main attached off of the top of that with your equalizer coming off of the end of the header. In the configuration you currently have, you're trying to push the steam in two directions, towards the equalizer and towards the main at the other end. Clearly the equalizer is a much shorter run so you are probably building pressure at the boiler before the steam has a chance to get pushed out the main and into the radiator runs. If the main was on the side, just before the equalizer, the steam would push out into the main, taking much of the pressure off of the equalizer and allowing it to "equalize".

Most of us heat our homes on ounces of steam (4 to 12 oz.) so the  pressuretrol really should rarely activate ( at those times when you are trying to raise the temp in the house 3 or 4 degrees or when it is zero or below outside and the boiler runs for extended periods) The pressuretrol acts like a safety device and to ensure the pressure is controlled. Believe it or not, steam travels fastest at lower pressures so you want to manage your pressure to be as low as possible, never over 2 lbs (even that is the top end of the spectrum).

I also see none of the pipes are insulated so steam begins to condense all along those pipes before it even has a chance to get to the radiators. One thing you can do is feel along those pipes in the basement and see where they are hot and where the heat stops. At the point where it stops will tell you how far along the path the steam gets. Also Make sure the main vent and radiator vents are adequate because if the steam can't push the air out of the system it will just push it as far as it can and sit there condensing. Make sure all the radiator valves are open. If some of the valves are closed, you are compounding your pressure problems. In a one pipe system, the valves need to be all the way open. You adjust the amount of heat in the room by the size/type of radiator vents you put on that radiator.

That mistery valve in the basement looks like a radiator valve. Is there any indication (like a whole in the floor above it) that a radiator may have been removed at some time? Not sure why they would have put the valve in the basement, unless there was not enough room next to the radiator to be able to get to it??

To your question about the difference between the Hoffman #74 and #75 vents, the #74 has a very small vent hole and is not designed for low pressure systems.

Fred

Radiator runs

The pipes that branch off of the main and go to the radiators are radiator runs. The pipe that loops around the basement is the main.

CapZ

multiple problems

You're right about the problem being around for awhile. As long as I can remember. A repiping, is probably off the table for the landlord, since it is putting out heat. And it may not be necessary. I'm going to try and lessen the problem for my neighbor by first getting the correct main vent and adjustable radiator vents. Thanks for the info on the 74 vent. The only reason I used a 74 was because that's what was on my system. Probably piped by the same guy. Both houses were built at the same time. And BTW I don't have a Hartford loop either. I'll also insulate what I can. I'll definitely come back and tell you all how its going. Thanks for the help. I learned a lot!

Fred

Efficiency

I assume the tenants are paying the oil bill. There is so much efficiency that can be gained by re-piping the near boiler pipe correctly. I would bet the boiler is running 30% to 50% more than it actually should to satisfy the thermostat (if it can even get the house to temp in its current state) Also, you say "it may not need to be re-piped". Trust me, it will never be right until it is. The vents and pipe insulation will help but won't fix the major issues. Also, without those Hartford loops, if you ever spring a leak in the wet returns, those boilers will empty out and, if the auto water feeders are working properly, it will flood the basement and the boiler still may not hold enough water to keep from running dry, cracking the boiler block and maybe even causing an explosion (not to cause you to be alarmed) but that is the minimum that needs to be done immediately Best of luck. Keep us posted.

CapZ

Progress

Ok I talked to the landlord and as I expected a repiping is out. The system really does put out good heat. I mentioned the Hartford loop is a good insurance bet if it springs a leak but I wasn't convincing enough. You can lead a horse to water......He did give me the go ahead to change out the vents and flush it out. The water was real dirty. I flushed it 3 times, letting it settle in between. It's still not clear, kind of like a light tea color. I cleaned the exchanger top and bottom and cleaned out the pigtail.I added the #75 vent and replaced the radiator vents with Heat timer varivalves. I set the pressuretrol at 0.5 +1 and fired it up.

The pressure is still rising to about 4.5 psi. The Pressuretrol does not shut it down at this point. What does shut it down is the CycleGuard performing the intermittent level test. Before, I mistakenly thought it was the Pressuretrol cutting it out. So it kicks back on after a minute and the pressure holds steady at 4.5. I noticed the water in the sight glass rises from a half to 3/4, then bounces a little, not violently. I had the varivalves wide open. There was a little hissing from a few radiators. One was outputting steam, same as with the old vent on it. The system did heat up fast but I would like to get an answer as to how to get the pressure closer to zero. I understand the Pressuretrol might be junk and should be replaced as a safety measure, and the piping isn't ideal, but I don't understand why the pressure gets so high. My system is setup so similarly, with no Hartford loop, or header as far as I can tell, and my pressure stays near zero.

CapZ

Also...

One more thing I want to add. When the system shuts down, either from the cycle guard or a satisfied thermostat, the pressure on the gauge actually rises a bit. It shut down and I watched the gauge climb from 4.5 to 5. Shouldn't it start dropping on shutdown? In what timeframe should it go to zero?

Fred

Combination of Issues

Capz, it is impossible to try and trouble shoot a system problem when so many of the important factors are taken off of the table, as if they can be worked around. The lack of a header is a huge issue. You mention this boiler is configured much like yours and yours works. Are both boilers the same size? This one could be over-sized for five radiators. Do you both have the same number/size radiators? Clearly the Pressuretrol is not doing its job or it would be cutting the burner off at about 1.5 lbs. Did you re-calibrate the Pressuretrol, per the instructions in my earlier post? If not, you need to do that or replace the Pressuretrol. Getting that corrected will probably resolve the hissing vents but may create short cycling at the boiler if the boiler has to run for extended periods of time to generate enough steam to satisfy the thermostat.  In addition to the piping issues, the lack of insulation on the pipes that are there is another big factor. Are you 100% sure the pressure gauge is functioning correctly? The rise in water in the sight glass is probably the equalizer set up you have with no Hartford loop. The steam pressure is probably pushing all the water in the wet returns back into the boiler. Just so many components that need to be considered and corrected that you are not going to find that "magical" solution that allows this boiler to run correctly when all of the piping rules have been broken. Try to calibrate or replace the Pressuretrol, make sure the pressure gauge is registering pressure correctly, see if you can get the landlord to put that Hartford loop in  and wash your hands of this problem until the landlord understands how important it is to include effective, efficient, properly working systems for his tenants.

CapZ

good advice

You're right Fred. I think I'll take care of the pressuretrol and point the landlord to this thread. Hopefully he'll take the necessary steps. Thanks for the help and sharing of knowledge. Very happy I found you guys. My system was a mystery to me for too long.