Water coming out of second floor radiator air vent after cleaning out entire steam system.

joeeddy

I am a heating contractor with a fair amount of steam heat knowledge. I recently had a call at 1950s cape style home with heat issues. Found everything about boiler operation to be dysfunctional. It is a gas boiler with 3 radiators on second floor and 5 on first. It has a 2 inch loop in basement with 1 inch and 1 1/4 one pipe runs to radiators. On arrival the flame was cycling on and off and most radiators were warm at best. After completely rewiring control circuit and replacing some parts including all radiator vents the boiler operation was working well with heat at all radiators including one on second floor that customer said had not worked in the six years since the boiler was installed. The boiler was installed six years ago with distribution piping much older than that. I felt because the flame was cycling it never had enough steam pressure to push to furthest radiators. All was well until a week later when water was coming out of this same second floor radiator vent and banging in the wall causing customer to close valve. I have since been there 3 times with various boiler cleaners and flushing pipes. Valve and radiator look ok and can pour water down pipe from second floor and see it getting back to boiler sight glass. Seems to be clear passage and water doesn't back up. This vent has been changed twice and have almost 3/4 inch pitch to valve side on 24 in x 24 in x4.5 inch radiator. Piping to this radiator is one inch and leaves the 2 inch loop with 4 ft of horizontal pipe to a 45 degree elbow to 16 inches of pipe to a 45 degree elbow to a 12 inch horizontal pipe to a 90 degree elbow that sits on sill plate above block wall . A 9 ft vertical run inside of exterior wall goes up behind kitchen cabinets to another 90 degree elbow to a 5 inch pipe to another 90 degree elbow and up thru floor with an 8 in pipe to valve. Inside wall is not visible but believed to be one inch pipe. I have considered 1 inch pipe is small but changing to 1 1/4 is not an option due to its location. Could the 9 ft vertical pipe inside the exterior be causing the problem if not well insulated? Why is there so much water coming out of this vent that the boiler needs replacement water daily? I am at a loss and would appreciate any thought or wisdom you could send my way.

Thank you,
Joe Eddy

BobC

Have you tried lifting both ends of the radiator? One of the short horizontal pipes might be out of pitch. It's also possible the radiator valve disk has broken off so it's trapping water in that radiator.

Bob

Fred

With the banging in the wall, my guess would be that 5" horizontal pipe at the top is pitched the wrong way away from the vertical pipe and with only a 1" pipe the steam is pushing that water back into the radiator the whole time the boiler is running. Can you lift that end of the radiator a bit and see if you can change that pitch a little to see if the problem resolves itself?

Steamhead

You might have enough pitch on that radiator to cause a water pocket in the 5-inch horizontal pipe under the floor. This can make a radiator do all kinds of nasty things.

Readjust the radiator so it is dead level. This should not affect the flow of steam and water inside the rad since a rad that new should have a passage along the top as well as the bottom, and the steam and water will have no trouble keeping out of each other's way.

If that doesn't work, try putting shims under all four feet of the radiator, as high as you can raise it without putting undue stress on the valve and piping.

joeeddy

Im sure those short pipes have hardly any pitch so I will try and lift radiator. Valves look ok but Ill check again when I go back. Thanks!

Steamhead

The other possibility is that something has gotten into the rad and is blocking the valve connection. Unlikely, but not unknown.

aircooled81

Is there a way to slow the steam entering a radiator, to allow condensate less counter velocity to flow? I thought i read somewhere if an airvent vents too fast, steam rushes in but condensate cant overcome? Am i seeing this in my mind right?

BobC

Slow venting will limit the flow of steam and lessen the condensate. If you vent to quickly it can cause problems, what kind of vent does that radiator have now?

Bob

Jamie Hall

Slow venting. Also, make sure that the radiator valve is fully open. Do NOT close the valve on a one pipe steam radiator! As has been said, you may want to make very sure that that valve really is fully open.

Also, check your pressure. Keep in mind that the cutout should be around 1.5 psi.

joeeddy

Thanks for your responses. Was away from computer yesterday. The vents I get at Universal Supply Group in North Jersey area. They are called Heat Timer Varivalve and are adjustable. Has a slide door on side, says Varivalve quick vent on it and made in Fairfield NJ. These valves have a different look than most vents but seem to be made well, not from China. I was more a fan of fixed vents from Gorton and Maid o Mist in the past but seems now only other various brands of adjustables are available at supply houses.
The pressure is set off at one pound. I spoke with someone at Wallace Ennace Assoc. on this who suggested bringing pressure down under one pound might help because the original older boiler usually ran at really low pressures. This is something I was going to try when I go back along with info that comes from this forum to help plan my next efforts.
Thank you for all the helpful input.
Joe

KC_Jones

Those vents are MASSIVELY aggressive and could be part of your problem. At 50% they vent more than a Gorton #1 main vent.

BobC

What kind of main vents does the system have? I'd try tuning the varivents down so they are almost off and see if things change.

You can buy Gorton and MOM vents at supplyhouse.com or Amazon.

Bob

joeeddy

Hi all. After accumulating thoughts and ideas I made another visit to radiator job. I noted the radiator in the opposite bedroom is piped the same way in an outside wall with horizontal nipples less the 2 45 degree Ls and it works. I dropped the pressure to one half pound, as low as possible. There is a main loop vent at end of return which is a Hoffman 4A quick vent. I lifted the entire radiator 3/4 inch, the maximum amount possible. Radiator valve is older but seems to open and close as much as new one . I tried adjusting varivent at all possible positions, drained out the last of 3 cleaning chemicals and installed a maintenance cleaner to leave in system. Turned heat on and in 10 to 12 min all other seven radiators on first and second floor were hot, entire 2 in loop in basement was hot back to boiler, and 1in pipe in basement going to non operational radiator was hot. At radiator on second floor it took 15 to 20 min with some pinging and banging but as valve and first section finally started to get hot I could hear water noises in the radiator. 30 sec after noises started water came out of vent with much force while the radiator was still mostly cold. I left with the valve closed and the radiator not in use.
The solutions that I am offering are a new radiator and valve on existing pipes. If no change I would repipe visibly in the next room with less Ls, pipe and not in outside wall with the new radiator and valve. I assume this would work but it would be costly. The electrician in me says go with electric baseboard at the lowest cost.
Thanks for your help and would appreciate your continued input.

Frustrated Joe

nicholas bonham-carter

Drain out the chemicals, and replace with pure water. If these chemicals are foaming, that will shoot a lot of wet steam and water up into the radiators. After all, when you have a shower, you rinse the soap off, after you have loosened the dirt on your skin!
I can't remember what your main venting is like, but if it is inadequate, then the excess air will be trying to escape through the radiator vents, bringing more water with it, and those radiator vents are notorious for spitting. It would be best to install Hoffman 40's, along with generous main vents to keep the air removal in the basement.
Probably, this system worked properly at some previous time, and the job is to find out what changed.--NBC

KC_Jones

joeeddy said:

There is a main loop vent at end of return which is a Hoffman 4A quick vent.

Frustrated Joe

Definitely not enough main venting.

joeeddy said:

The solutions that I am offering are a new radiator and valve on existing pipes.

Frustrated Joe

If the current rad isn't working what would a new rad accomplish? It will do the exact same thing as this one. You have a system issue that needs to be resolved. You are assuming the problem is the rad...its an empty shell that contains steam. A new empty shell that contains steam will perform exactly as the system it is connected to will dictate. You either have bad pitch somewhere (that needs to be determined) that is holding water, or a venting issue, or a combination of the 2. What chemicals did you put in the boiler? As NBC said some can cause issues, some are beneficial, but can cause issues in excess. Also closing the valve will potentially cause a whole bunch of problems one of those being to potentially fill the radiator up with water. The banging you describe is an indicator of water laying in pipes and/or wet steam. If it was me I would check EVERY pipe in the entire system for proper pitch as a starting point. Then get that main venting sorted out. Dump all the varivalves in favor of something much less aggressive. Then see where I was at with this. If none of that fixes the issue then would need to look a bit deeper. Could you post pictures of the near boiler piping? If it isn't proper you could be getting wet steam from that which will exasperate the issue.

BobC

I agree with everything these guys have suggested. Get a much bigger main vent and replace the varivalves with sme reasonably sized ones (Gorton, Maid O Mist, or Hoffmans). All that has to be done anyway for the system to work right.

Then put a level on every pipe you can reach and post pictures of you boiler and the piping around it. If none of these suggestions work it has to be a buried pipe that's pitched wrong, old buildings settle and pipes go out of pitch.

Bob

Fred

If water is coming out of the vent "with force" 30 seconds after the pipe and valve gets hot, it would suggest to me that maybe that radiator is flooded with water that can't drain out of the radiator. Have you taken the coupling between the radiator and the valve loose to see if something is blocking the water from returning, like maybe a broken valve disc or some other obstruction? With a 1" supply pipe, I assumed it is a relatively small radiator right? I would make sure I had a bunch of towels and maybe a container I could slide under that coupling to catch water. It may be a good amount.

nicholas bonham-carter

Take the valve bonnet off to check the valve, as it is easier.--NBC

Steamhead

Fred said:

If water is coming out of the vent "with force" 30 seconds after the pipe and valve gets hot, it would suggest to me that maybe that radiator is flooded with water that can't drain out of the radiator. Have you taken the coupling between the radiator and the valve loose to see if something is blocking the water from returning, like maybe a broken valve disc or some other obstruction? With a 1" supply pipe, I assumed it is a relatively small radiator right? I would make sure I had a bunch of towels and maybe a container I could slide under that coupling to catch water. It may be a good amount.

It's also possible something is stuck in the radiator- check in there too. Might just be a load of dirt or rust that needs to be flushed out.