New to steam

IMS47

Hi all, my wife and I just bought an old house with steam heat. I am new to steam, but I know my system has some issues.

I have a two pipe steam system, that has 6 radiators (3 upstairs, 3 downstairs), and 2 baseboards in an addition. 2 upstairs radiators have vents, and I think there is a vent on my condensate, but Im not sure because it was painted. There are no traps on any of the radiators, but there is a large pipe trap in the basement. There are 2 mains coming off the boiler, one feeds the front of the house and the other the back. Both radiator vents are on the back of the house main. My major issues are: the vent on one radiator sounds like a tea kettle, and the piping attached to this same vent bangs really loud. Also, I am just not sure my system is set up properly, it feels like it was pieced together over the years. Also, my boiler is almost new and runs well.

I work on HVAC piping systems for a living so this stuff makes sense to me, but I don't have much steam experience. I am hoping you guys can help me get my system in tip top shape. Thanks!

KC_Jones

2 pipes and vents on the radiators? Take pictures of this and the basement piping and anything else you are curious about. Let's have a look. The 2 pipes with a vent could be correct or it could be very wrong, we need to actually see the radiator to determine which it is.

Fred

Pictures please. Most 2 pipe systems don't have vents on the radiators. Make sure that radiator is pitched correctly so that water can run out in the right direction (if it is truely a 2 pipe, pitched to the pipe opposite the steam inlet pipe). Also tell us what your Pressuretrol is set at. It should be set at .5PSI cut-in and Differential should be set at 1. If the Pressuretrol is an all grey unit with one scale on the front, take the screw off at the bottom center of the Pressuretrol, on the front cover and you should see a white wheel inside that sets your differential. Also make sure the pigtail (looped pipe that your Pressuretrol is mounted onto) is not plugged. That loop can , and often does get plugged with gunk and the Pressuretrol can't see the steam pressure. If the pressure gets too high, either because of the settings or because the pigtail is plugged, that can make vents sound the way you describe.

IMS47

Here is the boiler, the main to the right is the front of the house, the main to the left is the back. On the trap, the steam feeds into the left side and condensate on the right. This is the only trap other that the condensate at the boiler. The radiator is one of two with a vent, both are the same. This one sounds like a tea kettle

IMS47

The pressuretrol is set to .5 cut-in and the differential is 1. The cut-in was slightly lower than .5 when I checked so I adjusted it.

nicholas bonham-carter

The supply pipes are wrong, with both risers feeding the header in the wrong place, and you no doubt will need more main venting.
Noisy vents indicate higher than normal pressure, for such a system (ounces). And they are probably not needed.--NBC

Fred

Shouldn't need vents on a two pipe radiator and the drain pipe on that radiator is pitched towards the radiator. It should be pitched the other direction so water can run back to the boiler. That's probably what is causing banging at that location. Also, when is the last time you took the pigtail )(the looped pipe the Pressuretrol is mounted to) off and cleaned it out. It it is plugged with gunk, the Pressuretrol can't see the pressure even though you set it correctly.
EDIT: That's a Sarco 8T vent you have there on the main. They are cast iron and probably original to the system when it was coal fired. They only vent a .5 PSI at 1 ounce of pressure. About the same as a Hoffman 75. I'm sure you need more venting on your system, as well.

IMS47

That line is just slightly pitched back to the rad, but I need to fix it. Bigger problem I found is that line in the basement is pitched the wrong way by at least an inch. Need to figure out how to lift that whole run an inch or so.
As for that vent, I am going to replace it, what should I get? The vent is on the return line. Again I have 6 rads and 2 baseboards. The house is just over 1600 sq ft. And when I replace that vent, should I remove the rad vents and just plug that whole?

Fred

If you fix the pitch on that pipe that connects to that radiator and properly pitch the pipe in the basement and make sure any traps on your system are working properly (I don't see a trap on this particular radiator) you should be able to put a plug in the hole where that vent is. If the pipe in the basement is pitched in the wrong direction by an inch, if it's the supply side, it probably isn't letting much steam get to the radiator. If it is on the return side, it probably has enough water in it to block air from escaping.

IMS47

Any advice on what vent to get? The only main vent is on the condensate side.

KC_Jones

You need to measure the length of your mains and the pipe size. That will determine how much venting you need. It is very possible you will need more than one vent. The rule of thumb is 1 Gorton #2 vent for every 20' of 2" pipe.

SteamedInWharton

@IMS47 your pictures reminded me of another system I've seen on this forum: http://forum.heatinghelp.com/discussion/147914/please-help-with-banging-steam-pipes/p1

both the loop traps and radiators without traps look similar.

I'm a mere novice at these things (just a single pipe homeowner), but if I'm correct (and @Steamhead can confirm), you have a two-pipe vapor system designed to operate at OUNCES of pressure controlled by a vaporstat and not the 1.5 lbs setting that's the lowest allowed by a pressuretrol.

Most two-pipe systems use radiator traps that close too keep steam out of the dry returns while allowing air and condensate to exit when the trap is open. A vapor system has no radiator traps, it relies on a small orifice on the input valve that combined with low pressure allows a small, controlled amount of steam into the radiator that doesn't exceed the radiator's condensing capacity and keeps steam from entering the dry returns despite lack of an actual seal or trap.

Steamhead

Most of them do use traps, but as Steamedinwharton says, this is an exception. This does look like a Tudor or "orifice" system, in which the radiator valves have orifices which allow only enough steam to fill the radiator about 85% with steam as long as the pressure doesn't get too high. If the return elbows on the radiators are wide-open, without anything in them, it's a Tudor.

First thing to do is add vents to the ends of the steam mains based on their length and diameter, and replace that dry (overhead) return vent. I'd use a Gorton #2 on the dry return. Remove the vents on the radiators and plug their openings; you don't need them.

Then replace the pressure control on the boiler with a Vaporstat which will keep the pressure low enough that the steam shouldn't reach the dry returns.

Then watch how much better it works.

IMS47

That's for the info. I will get the Gorton #2 for the return but what about the supply mains? Each one is about 3' long.

As for the vaporstat, if I replace what I have now, what settings should I use? I have the current one set at 0.5 psi.

How sure are you that this is a Tudor system and needs these things? I only ask because I'm going to spend a few hundred bucks on parts based on a few pictures. Thanks for all the help.

Fred

If the Mains are only 3' long, one Gorton #1 on each main will be enough for those. Those are really short mains?? As for the Vaporstat, when you get it, you will want to leave your Pressuretrol on the boiler as well. Put the vaporstat on a seperate pigtail and mount it somewhere else with a low pressure gauge (0-3 PSI) , if possible. Leave the Pressuretrol on it's own pigtail. That will become a back-up safety device should the Vaporstat fail, the Pressuretrol andwill still cut the boiler off on pressure. Using two seperate pigtails will help ensure that if one get plgged up, the other will likely still allow the device to see pressure. I would set the Vaporstat at about 4 oz. cut-in and a Differential of about 8 oz. for a cut-out of 12 oz.

KC_Jones

IMS47 said:

Each one is about 3' long.

I am guessing that is a typo? I see more than 3' in the pics you posted.

IMS47

Yeah, that was a typo, each main is about 30' long.

Fred

So you need one Gorton #2 and ywo Gorton #1's on each of those mains. Of course you can use two Gorton #2's on each main, if you want. Depending on which is least expensive.

EBEBRATT-Ed

Maybe I am looking at this wrong but you need the air vents on the radiators and there are no traps because the radiator returns are connected with loop seals. It's a two pipe air vent system. Most all the air is vented at the radiators air vents. You have to keep the pressure really low so you don't force the water out of the loop seal. I can't see the overhead return being a dry return because it carries only water-no steam.

Ok, If I'm wrong let me have it with both barrels. And yes the boiler is pipe wrong. Steam in the header being pushed from both directions and the header size???. also, does it have an equalizer??

Fred

Steam is geeting to that return that has the old Sarco vent on it. I would guess that is before the loop seal.

KC_Jones

On 2 pipe air vent systems the radiator is generally connected at the bottom on both sides with a standard radiator valve. This one also has a more classic 2 pipe valve on the inlet that is adjustable. Also the pipes don't appear large enough for 2 pipe air vent I would expect something sized more like a one pipe system. I am with steamhead on this one.

Steamhead

Tudor System info:

https://heatinghelp.com/heating-museum/european-heating-systems-circa-1907/

IMS47

The diagram in that manual is spot on how my system is set up.

It seems like over the years everyone who has owned my house has tried to fix it without knowing what they are dealing with. Here is my plan, in the order I plan to do it, let me know if I am off base.

1. Replace return vent with Gorton #2
2. Remove radiator vents and plug holes
3. Switch to a vaporstat
4. Add vents to the two main run-outs

Fred

Do both of your mains tie back into that return that has the old vent on it? If so, you can put all your vents at that location. I think that old Sarco vent is a 3/4" threaded opening mounted on a 3/4" pipe. If so, that should be sufficient for all your vents.

SteamedInWharton

From his pictures, his mains to tie into the return, but through loop seal traps to return condensate instead of crossover or F&T traps to vent the air. He'll probably want to vent the mains separately.

IMS47

OK, so I replaced the old vent with a Gorton #2, fixed all the return pipe so it pitches the correct way, and removed all the radiator vents and plugged holes. Haven't added main vents or vaporstat yet, but I will in the next few weeks. I still have a loud bang on my return when the system is running.
I did some research and found when the system is hot, all of the radiator inlets are nice and hot and the returns are cool to the touch, which is correct, I think. The two baseboards I have get scorching hot, and the returns feeding back into my condensate return are really hot. Over a short period of time, these baseboard returns make my condensate main really hot. Once it's nice and hot, the banging starts. And the banging is coming from the radiator that is out past where the base board returns tie in.
It seems like the steam in the baseboards isn't condensing like in the radiators, and dumping steam into my return main. If I understand this stuff right, that's bad. There are no traps on my baseboards, would it help to install them?

Jamie Hall

Uh... yes. If those baseboards are making the return hot, like blazing hot, there's a good chunk of your problem Traps are indicated!

Steamhead

Instead of traps, I'd use orifice discs. These go in the baseboard supply valve unions and are drilled out just enough to heat the baseboard to near the end at the system's maximum pressure.

This way, all your radiation will work the same way.

IMS47

Ok, so it's been a while, but I am finally getting to adding the Vaporstat to my boiler. I'm looking to get some help wiring it up. If the terminals were the same, no problem, but since the are different I am a bit lost. Below are the pressuretrol and the Vaporstat, if anyone can tell me which wire's go where, it would be a huge help.

Fred

Most of us keep both the Pressuretrol and the Vaporstat on the boiler. The Pressuretrol becomes a back-up to the Vaporstat. In that case,They are wired in series. Otherwise, one wire (either one). from the pressuretrol goes to the top terminal on the Vaporstat and the other wire goes to the bottom terminal on the Vaporstat.

IMS47

Ok, got it all set up. What settings should I use on the Vaporstat? My plan was 4oz on Main, and 8oz Diff. Last year, I put a low pressure gauge on and the highest it ever read was 4-5 oz. Do these settings make sense?

Danny Scully

No, the difference is subtractive. So, the opposite.

vaporvac

Did you ever get the pitch corrected? You mentioned after making many of the changes you still had banging. Until the pitch is fised to will continue to have it. Even a small amount get result in that. @Jamie Hall wrote about his rad a couple of years back and you wouldn't believe how such a small discrepancy can make such a loud noise. For pipes in the basement, you may need straps to help raise it. I had to do the same on my vacuum equalizer line; it was more that two" out of plumb and shook the all the lines on start-up. It's completely silent now.

IMS47

Danny- so 8 on main and 4 on diff?

Vaporvac- I did get the pitch issue squared away. By the end of last heating season i had no more banging pipes.

Danny Scully

Correct, that would cut in at 4oz (8-4) and cut out at 8oz. Just as an example, if you set the main to 8 and the diff to 6, it could cut in at 2oz (8-6), and cut out at 8oz.