master radiator vent, one pipe steamer

ch4man

found an odd one today, one pipe steamer, it appears the original design was to tie all the radiator vents to a common master vent. all but 3 were changed to conventional vents, hoffmans or gortons.

only one abandoned vent line was plugged. 2 were still connected with what looks like adjustable needle/seat adjustable vent rate assembly. and one still had hoffman vent(the chrome one) which looks to be what most all of the others were based on the nuts at the abandoned pipe.

thoughts. was this ever common?

Jamie Hall

Interesting. One has to wonder -- was this ever a vacuum system? If all the vent lines were tied together, it wouldn't be that hard to do...

ch4man

i had that thought as well, i cant find any info on the remaining hoffman vent. im hoping someone here has an idea. i'm mad at my self, didnt take pictures in the boiler room. nothing out of the ordinary except the 3/8" piping system that tied together to TEE where one larger air vent was. this "vent" system also tee'd into the return below the NOWL. all dry returns.

the steam header was typically screwed up. 2 risers used, but one tied into the header between the 2 main takeoffs. was short cycling on lwco, a MM 802.

whats i cant explain was the boiler was slightly overfilled. we corrected that by skimming through the relief ( yeah i know that was wrong). however.. in doing so the boiler was firing and the gauge glass on one side showed very low water level, yet we still had water skimming from the releif on the other side.

was it because of some left over oils ( this was the 3rd skim), or becajse we were slightly overfilled, the screwed up header or a combination?/.

when done it all settled down. p.s boiler is a new burnham IN5

EBEBRATT-Ed

Boiler water level can vary back to front or side to side. Could be one or more of the following problems:

Undersized risers and header causes high velocity to pull water toward risers

Skimming, dirty boiler water

Over fired or wrong nozzle or flame pattern

the_donut

Definitely a vacuum air line system base on size of tubing. Probably tied together to a vacuum device. Instead of replacing the pump or injector, they tied together with a master air vent. It didn’t work out after the hoffman thermostatic vents failed so they removed the problem sections and put air vents in.

Vent is probably a hoffman model 3 air line valve.

Takeoff is undersized drawing waterline up on header side. Pictures would be helpful. Problem is, the system piping is probably undersized because vacuum systems used a size or so smaller on piping. This will cause issues with condensate causing hammer due to not enough room in pipe for flow.

ch4man

the_donut said:

Definitely a vacuum air line system base on size of tubing. Probably tied together to a vacuum device. Instead of replacing the pump or injector, they tied together with a master air vent. It didn’t work out after the hoffman thermostatic vents failed so they removed the problem sections and put air vents in.

Vent is probably a hoffman model 3 air line valve.

Takeoff is undersized drawing waterline up on header side. Pictures would be helpful. Problem is, the system piping is probably undersized because vacuum systems used a size or so smaller on piping. This will cause issues with condensate causing hammer due to not enough room in pipe for flow.

thanks for the links, that answers a lot.

the risers were full size and header is larger., since skimming and lowering the waterline helped im assuming the waterline does tilt due to the messed up header. lower waterline and clean water keep the high side of the water line from getting pulled out or on riser. home owner says there is NO hammer, says its a very quiet system

i think?

the_donut

My concern is the tilting water line setting off an automatic feeder and flooding the boiler during a cold spell after a setback because of long cycles and slow returning condensate.

Fred

How high are the boiler risers before they connect to the Header? The higher the better, to prevent water being drawn up into the system. I have a 116 year old home and the piping configuration is the same as you describe. Mains are tied into the Header between the boiler risers. All piping, except the boiler risers are original. Risers out of the boiler are 4 feet up to the Header and the system runs beautifully. It is quiet, dry steam, even heat. The boiler is 35 years old and when it finally dies, I will change the configuration but there is no reason to do so until that time. Keep the system pressure low as well. I keep mine at a 4 ounce Cut-in and 12 ounce Cut-out. System typically runs at about 2 ounces unless we get down to or below Design Day. I'm guessing the pressure in the system you describe is running higher. Good Main venting will help a lot.
Are those vent pipes that have been disconnected at the radiators still connected, on the other end, to the venting system? I'm wondering if that has some impact on the behavior of the water level?

ch4man

has an xvt set to 1 gallon, 2 minutes.

time will tell

ch4man

fred, i really wish i had pictures.. the header is just a 3" pipe capped at both ends with 5 threaded pipes about 3" long each. 2 on top, 3 on the bottom. the rises start about 10-12" then ell over 5-6" and the ell up to the bottom of the header. 25" above NOWL.

im wondering if its possible that the far end riser overpowers the other feeding the mains and blocking the riser thats between the mains causing the pressure imbalance

Fred

@ch4man , If the header is capped at both ends, where is the equalizer? If it's not on the end of the Header but on the bottom of the header or off of one of the other pipes/riser, that may be a source for some of the water problem. I feel like having the mains tied in between the boiler risers will more likely cause an imbalance in steam flow to each main but I doubt it has enough inertia to block a riser. Fortunately, in my case the connected EDR on each main is pretty much equal so it seems (at least my theory) that each boiler riser is most likely favoring the fill requirements of the main nearest it. If there were only one main, I'm sure the steam from each riser would collide. I have a 5" header too. That has to help my situation.

the_donut

I assume the 3rd pipe going down is to a equalizer and 2 up are going to separate mains. If this is the case, one main vent may be plugged. What’s the main venting like?

ch4man

oh dear,,,, donut i failed to include main vents. there are 2 mains, both vented through 1/8" welded nipples. one has an old unidentified vent, the other a hoffman radiator vent. A1 i think. but what can you do with 1/8" tapping. yes third tapping on the bottom is for the equalizer. 1-1/2" and is as spec'd for per install manual

i didnt do it, was just here to figure out the low water condition a week after install

Fred

@ch4man said: "however.. in doing so the boiler was firing and the gauge glass on one side showed very low water level, yet we still had water skimming from the relief on the other side."
This is very telling. What is causing the water to be that tilted in the boiler or is the sight glass not representative of the water level in the boiler? Are you sure both the upper and lower gauge glass valves were fully open?

the_donut

1/8” will vent 2.5 cfm at 3 ozs of pressure. That’s enough to feed a gorton #2 or a Barnes & Jones vari-vent. If it is a 1A, max cfm is 0.3 cfm at 3 oz, which is less than an eighth capacity. The Hoffman 3 air valve on the one radiator pulls 0.42 cfm at 3 oz. which may be higher than all the main venting. The unidentified vent may be an older vacuum vent.

I am leaning towards the main on the right takeoff facing front of boiler is pulling steam much faster than the left. It may be the venting is much faster on this side or the connected edr is much higher.

I’d take some pictures, measure pipe sizes and lengths. Sounds like more venting is needed and most of venting is being done at radiators.

Fred

A 1/8th inch tapping is something less than that with a vent screwed into it. That coupled with the fact that I don't think a 1/8th inch tapping is enough room to let steam into it and any condensate out. Larger vent may not work reliably. It would be much better to find a place to put a larger tapping or Tee for the main vent.

Steamhead

This was likely a Paul system. See chapter 15 of Lost Art for details. Perfect place for a vacuum exhauster.

ch4man

so what i found is this....

i had found a one pipe Paul system varient, or maybe an air line system.
maybe the difference between a paul and an air line system is if it utilized a vacuum pump or not, or if one pipe or two.

https://heatinghelp.com/blog/its-a-wonderful-life/

the_donut

Hoffman 3 is Paul system. Air line is just broad category that Paul falls into. Air line is vacuum. Would be some work to get system back to original. Depends on owner.

ch4man

going back to original aint gonna happen. 9 of 12 radiators have been updated. of the last 3 only one has a hoffman @3. the other two are still ones i haven't identified and may be gutted as there is nothing inside them ( i looked )

its heated fine for years, im just here to dial in the new steamer

ch4man

well i may have a chance for more pix. im on the couch watching the race and i get a text from a coworker whose there now watching it short cycle and and pump water somewhere.

stay tuned

Mike Cascio

If all the lines are still present, it would be a great opportunity to put back the paul system. The #3 vent is still available from hoffman and a modern vacuum pump can be installed. The fuel savings would be tremendous.

ch4man

before



after



still short cycles on LWCO at 3/4 psi boiler pressure? all rad vents changed to A1's set to 5 and 6. the last 3 rads on the Paul air line have been changed to vents

nicholas bonham-carter

Those Hoffman main vents are only good for about 10 running feet of 2 inch pipe, so you most likely need more capacity.—NBC

ch4man

they're a lot better than what was there!