In a Gravity feed, Vapor system

Steam Bunny

When 1) wet return carries
a) condensate from the steam mains and
b) *wet* condensate from untrapped indirects.

2) dry return
a) carries radiator condensate (Mouat traps) &
b) utilitizes untrapped indirects to pass air from the supply to return side.

If I find, with the new boiler, I can’t prevent steam escaping from the indirects into the dry return, could I be asking for problems if I disconnect the indirects from the dry return, preserve their access to the wet return, and give each it’s own vent?

Steamhead (in transit)

You could do that

or you could insert traps in the air lines from the indirects. either way would work.

Steam Bunny

I can’t believe you understood

what *I* wrote, Steamhead! It’s as if you’re standing in the basement! This part of the system has entertained me for months, and I still don’t get it-

for simplicity I’ll relist the description of the return piping:

****

1) wet return carries a) condensate from the steam mains and b) *wet* condensate from untrapped indirects.

2) dry return a) carries radiator condensate (Mouat traps) & b) utilitizes untrapped indirects to pass air from the supply to return side.

****

If I trap the indirects is it possible I could lose the extra steam pressure needed to return the condensate to the boiler (am attempting to avoid a boiler feed pump)? Can I ignore the rules from 0 to 8 ounces?

The indirects tend to congregate at the ends of the sub mains (6 are paired- eg 3 Siamese twins- & my middle name is “Steam Chaser” :-/) If we vent in order to disconnect them from the dry return, are we then effectively venting the main? If this isn’t standard fare in a two pipe system what would be the cost? When venting is isolated from the dry return, perhaps as a closed circuit, is it possible there’s no cost? (I’ve been trying for months to visualize cause & effect but, thus far, the gray matter refuses to cooperate.) Am I dealing with steam, pressure, air, ghosts? H E L P ! ? ! ?

Would either one of the above *solutions* have an advantage over the other?

gerry gill

are you sure your

blowing steam into the dry returns? or are the indirects orificed in some way? why do you think you need a boiler feed pump Vicki? cause someone told you you do? cause its the easy way out? the tank would work and gravity beats pumps anyday..

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Steam Bunny

As even I wasn't able to understand what I wrote, I've attempted to translate my previous post and the follow ups into one drawing. Am wondering if this approach could effectively *isolate* a few errant 1 pipe steam radiators from the otherwise intact 2 pipe system? (would prefer not to repair them right away but don't want them muddling the system when it first comes up)

If it is a viable solution, would I be losing any efficiencies or advantages by doing this?

Steamhead (in transit)

Trapping wouldn't make any difference

to the dry return, since there's not supposed to be any leftover pressure there anyway due to the Mouat water seals. When steam reaches the traps, they close. That's it. That keeps steam out of the dry return.

The WET return connections from the indirects should not be routed thru the traps, for precisely the same reason: You NEED that leftover pressure in a wet return connection, otherwise water will back up into it.

But Gerry is right: it's hard to believe the Dead Men didn't make some provision for keeping steam out of the dry return when they put those indirects in. So, are you actually getting steam flowing from the indirects into the dry return?

As I said earlier, those 1-pipe rads that were 2-pipe originally need to be changed back to 2-pipe. That's the only way they will work right on this system.

gerry gill

i dont know if it will help..

cause i don't know if there is steam in the returns from the indirect..there may be no trap cause maybe, just maybe, mouat had some restriction built into the supply pipes feeding the indirect, rendering the traps on the indirect meaningless..if so, putting the air vent there would do nothing..but if your blowing steam thru the indirect, then yes your plan should work.

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Steam Bunny

Trap only the indirect’s dry return.....

An absolutely incredible unobviously obvious suggestion! –AND Steamhead's still alive!

But before I relay what I realized as a result of his post (almost drew it last night, without thinking- duh) I've got to ask if someone might help me with 2 issues- first is a no brainer, but (perhaps because I got it) I just don't get it.

A) I'm having difficulty understanding why 1 pipe radiators shouldn’t be on a 2 pipe system. Is it because

1) risers aren’t piped for 1 pipe

2) do they somehow raise havoc with 2 pipe steam supply?

3) is it a matter of balancing the system? only on or only off?

4) None of the above

Could inadequate venting be, not the cause, but a contributing factor to the freezing that created the 1 pipe situation before we moved in? Through trial, error, & a bit of hindsight comedy, I've become VERY familiar with how to get air into water lines if one expects to do a successful solder. Consequently, I've been defensively inclined to vent both the main and the dry return (air from both supply & return sides) if it could help to release the condensate more quickly, make a freeze less likely, and not lower the efficiency. In other words, I wondered if I might magically solve multiple issues by venting the indirects to the wet return, particularly if the wets need to be replaced.

All 1 pipes are on the same sub-main and have the least access to all but the Mouat vent. I can't even confirm the Mouat was part of the original installation. But, if inadequate venting could contribute to freezing, in a 3000 edr system there is:

1) Mouat Air Vent end of dry return

1) Hoffman 75 off primary main at first drip riser

1) Dole #5 an indirect dripped to wet return
&, I all but forgot the one on the WET return

Thanks to Gerry & Steve’s “Venting Capacity Chart” I don’t have to get my calculator out to know these don't replace Mouat’s 1” chimney vent.

Am working on the next post, attempting to translate answers to your questions into *Steamglish*. Clear, concise, articulation is not one of my strengths, particularly when it entails foreign doohickeys & thingamajigs.

Steamhead (in transit)

If I remember correctly

those 1-pipe rads were originally 2-pipe, and the returns were eliminated. Since the steam lines to the rads were not sized to handle condensate flowing against the steam, they probably bang a lot.

I'm curious as to why the pipes froze. Normally these pipes drain dry when the system is off. Maybe they got off-pitch somehow, trapping water in them?

Steam Bunny

Is that it?

The supply to the two 1 pipes I occasionally turn on, share a 1 ½” supply riser. Both it & return are pitched @ 45 degrees). 1 ½” riser is also shared by an intact 2 pipe for a total EDR of 88 (may be 2 others on riser, but I’ve never had them on). Most ‘banging’ is quite minor, pipe expansion "I have arrived" type noises. If they don’t cause banging is it still preferable to convert them back to 2 pipe?

I don’t wonder about the frozen returns, I’m paranoid! Two other 1 pipes with undersized piping (I rarely turn on) would be relatively easy to repair, but if the problem isn’t corrected, down stairs there’s a 16 ft high molded plaster ceiling for the condensate to go play in. I just checked and their down risers are not off pitch.

I’ve speculated, if the Mouats were in a supply side vacuum, the traps might drip condensate too slowly -permitting cool down to ambient temp before entering the return risers... And if outside temperatures were cold enough, it could be feasible to get a build up of ice droplets in the return riser in a relatively short period of time. Could something like that happen?

gerry gill

isn't your return pipe vented

into the chimney? i'm trying to visualize a supply side vacuum with a vent pipe into the chimney..

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Steam Bunny

No Gerry, It's still connected to the chimney but not the boiler. Because it'd been a part of the heating system I thought it would be best to just leave it. I love historical tidbits- even if they're rusty.

Also, when I answer your question re steam in dry return....
For years we'd have occasional plaster *droppings* off our music room ceiling. I'd go crazy- couldn't find the cause & was concerned it could be the steam pipes. Finally when I took the roof off- there it was. The clown who "repaired" the frozen pipes (converted to 1 pipe) never capped the return side. Also, when I'd move a radiator to sand a floor, etc. I'd close up both sides because I knew, when I wasn't looking, the return side might decide to have fun with the wall paper, too.

Steam Bunny

I spent last winter chasing steam with an infrared thermometer. In all fairness to the system, steam doesn't enter the dry return until the radiators are filled with steam when, with a perfect boiler, the input btu's could be cranked down.

ALSO, I shouldn't forget, the boiler had a small crack in the steaming chamber, and that certainly could have changed the dynamics of the system in some fashion, & new boiler could change it, too)

Mouat connected the indirects (72 to 102 edr) to his Mouat Power8 Valves (???) (see attached photo for clarification). The valves should all be in working condition. Perhaps these valves were the equivalent of variable *orificing* for steam control.

Last winter each major Siamese twin would dominate its minor & I doubt orificing the valve would correct this. (see below & if it won't work, I drew it wrong) I show 1/2" pipe in red which apparently Mouat intended to use as a steam restrictor/orifice??? Would appreciate more information on this if anyone knows. It appears after our home was built he made them quite a bit longer, but I'm not sure because people have stopped inviting me to their homes.

gerry gill

what controls the powers valve?

is it air driven? capillary tube?

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Steam Bunny

I presume it was pneumatic, but don't have the know how to be positive- attached is what's in a side room. Maybe you can tell from that?

Unfortunately, or perhaps fortunately, most of it had been disassembled before we moved in.

Steam Bunny

I presume pneumatic. Appears to have been interconnected by 1/4" (??) black pipe. Photo marked Heat Regulator has a piece above it. (see attached)