vapor vacuum heating co. Philadelphia

kev

This is the name on radiator lever valves of a two pipe no traps steam system I looked at recently.The boiler is flooding and the supply mains are banging. The boiler was replaced 5 years ago and the owner claims the system worked but heated very unevenly. Believe it or not the old original boiler is still there in place and connected though valved off. The supply mains (2) are pitched away from from the boiler to the far side of basement and drop down before they connect and run back to boiler. The returns are all dry and parallel The mains ending with a main vent befor dropping down into the returns at boiler. First thing I notice is the original water line was about four feet off the ground, which now makes the supply returns dry. New water line is about 18" off floor.  The hangers on both supply and returns are in need of some work to create proper pitch and I plan to correct. The dry should be wet returns will be lowered and replaced.

The questions I have are, can I replace the main vent with a hoffman 75 or similar? It seems as though the system is totally closed except for this vent. Would main vents help on the ends of supplys? I have been unable to locate and info on this particular system and would appreciate any directions to some . Thank you.

nicholas bonham-carter

old vapor system new boiler

this looks like the type of system which meters only the amount of steam into the rad, which can be condensed, so there may be an orifice or a metering valve in the supply end to adjust.

this sort of system used very low pressures, when the boiler was firing, so is there a vaporstat set to a few ounces?

you definitely need some main venting-more than a hoffman 75-more like a couple of gorton #2's each. the old vent may be a vacuum vent which would not be right with a modern boiler. 

i would also suggest those wet returns be down as far as possible below the waterline, with a straight shot down from the end of the dry returns, as any horizontal piping at the waterline height can play havoc with the waterline itself. are the returns still connected to the old boiler? that could hide some water as well under pressure [even a few ounces]. 

if it were mine i would cut off any auto fill there may be, and go with gravity, for a while at least. this boiler may never have been skimmed, and thus would benefit from that.--nbc

kev

Main vent

There are no vents out at end of supply mains. Only one vent at end of return mains before boiler. I was thinking that I do not need to vent very rapidly as the rads do not pass air quickly. Am I wrong and should these mains vent as rapily as possible?  The returns do not pass through old boiler (valved off ) but I will be correcting this by disconnecting all piping and moving returns lower. Would vents at end of supply mains help or should I leave as is?  Thanks.

Jamie Hall

I is almost impossible

to vent mains too rapidly.  Radiators, yes -- but that's not the case here.  The main vents really do two things: let the air out of the mains, and let the air from the radiators out of the mains.  On systems of this sort, there really is no need for there to be main vents on the ends of the mains -- provided that there is a way for air in the mains to get back to the main vent(s) at the boiler.  That means that there are dry returns, as well as wet returns.  If there are no dry returns, then there must be main vents at the ends of the steam mains (otherwise, where is the air going to go?).



It is possible that the system never did have wet returns; some don't.  If the dry returns are pitched to return to the boiler, they will carry the condensate back to the boiler quite happily -- as well as the air.  One possible problem, though, is that if the pressures are too high you may get steam in returns, which will pretty well stop any heating (as well as possibly holding condensate back, which may cause a water line or flooding problem in the boiler).



Since it is unlikely that you can raise the new boiler so that the water line is where the rest of the system wants it to be, can you pipe in a false water line arrangement at the boiler instead?  That might help a lot, and save the trouble of lowering all of the returns.

Steamhead

The Vapor Vacuum Heating Company

was the company that marketed the Kriebel system back in the day. Have you opened the return ells to see if they have "bafflers" (little check valves) in them?



The bafflers kept vapor that might have gotten into the dry returns from flowing into the radiators thru the return connections. Otherwise, the Kriebel is basically an Orifice Vapor system. Interestingly, in its original configuration, the Kriebel system did allow steam into the dry returns in order to close the main vent and form a vacuum. That vent was about two feet long and usually mounted on the basement ceiling near the boiler.



I'd use Gorton #2 vents to update this classic Vapor system. Here are some pics of a Kriebel where we replaced the boiler, rebuilt some of the hand valves and added vents.



You can find the Kriebel in chapter 15 of Lost Art.

kev

Thanks

Kriebel it is. There is no longer a main return/vent doohicky hanging in basement. I lowered the two main supply returns so they connect below water line and ran back to boiler, Removed main vacuum vent on return and installed #75 and corrected any missing pipe hanger and pitch issues. The system ran noise free and rads where piping hot. I removed a cap from a return ell at radiator and could watch the check valve burp the condensate, very cool.   Thanks for the replys.

Steamhead

And I'll bet

the owner thinks you're a hero!