2-pipe return system

HansL

New here and to boilers in general.  We moved into a 100yo house with a 2-pipe system.  11rads total on two stories with boiler in partial basement. The system had not been well-maintained with a lot of sediment in the boiler and sight glass.  After a couple rounds of 8-way, the sight glass is clear and staying so....

Question:  the system has two condensate returns down into the boiler.  A dry return suspended from the floorboards that drops into a vented reservoir and is pumped into the boiler.  There are also two parallel gravity return pipes along the crawl space from front to back of house and then drop at 90degrees to a went return that runs along basement perimeter to the boiler through a loop (Gifford I think?)

Is this dual return system normal?  The gravity return hammers really loudly pretty early in the cycle and there is a leak in a stretch of the “dry” part of the return that will be replaced by a plumber soon.  I haven’t been able to locate an F&T trap on the gravity return piping...should there be one?  If so, where?  I do not know how the upstairs rads are plumbed and don’t know which radiator is the end of the main, so no idea where to look for a trap.

Any insights from this group would be much appreciated!!

Thanks

Jamie Hall

It will be essential to know how the radiators are plumbed, and what -- if they have two pipes (inlet and outlet) fittings are on the outlets. Pictures of a typical radiator will help -- a lot.

Returns can give a lot of trouble if the elevations are wrong. You mention a wet return. What is its elevation in relation to the boiler water line? It should be at least a foot below the boiler water line for its entire length -- if not more. Then you mention two parallel gravity return pipes. What is their elevation with relation to the boiler water line? Are there radiator returns connected to any of these pipes? Then you mention a dry return which drops into a vented reservoir which is pumped to the boiler. What connects to that dry return? Radiators?

You enquire about an F&T trap on the return piping. No, usually one should not be needed. They serve one purpose, and one purpose only: to separate a steam main, carrying both steam and condensate, from a return line carrying only condensate. They allow condensate to pass, but not steam -- and there are better ways to do that if the elevations are correct. The presence of a vented receiver, however, can complicate things tremendously in that regard (as well as in other ways...).

If the elevations are off, it's not surprising that the gravity returns hammer.

So... a few pictures, if you can, and perhaps a nice sketch of what connects to what, and the relative elevations of things would be quite helpful here.

EBEBRATT-Ed

It's likely that the dry return couldn't be pitched enough or there were obsticals in the way so they used a condensate pump. Not that unusual.

A condensate pump has a vented overflow so that requires steam traps somewhere or a loop seal

Pictures will help of the boiler, piping around it, condensate pump and a few radiators

Steamhead

Either that, or there used to be a Return Trap and someone replaced it with that condensate pump.

In most cases, a Return Trap was there to make sure the condensate could return if the boiler pressure got too high. On a modern boiler, we get around this by using a Vaporstat instead of a Pressuretrol.

Where are you located?

HansL

Here are some pix of near boiler plumbing...Weil-McLain 

HansL

HansL

Here are some pix of return at boiler...went return along basement perimeter...vented pump and dry

HansL

Wet return coming into basement from crawl space.  Pitch in crawl could be an issue, but wet lines come in 2-3ft above boiler water line (see white pvc marking approx water line)

Each of the gravity lines also have a Warren Webster 512 trap on each that drips into the dry line that goes to pump.

HansL

We live in Greensboro, NC and would love to connect with a steam guru in the area.

Winters are pretty mild down here but we still need heat.  

Once the system is hot it does a great job heating the house.  Have vaportstat and new gauge ready to install that will hopefully make it that much better...

I wish I had a better sense for how the system is plumbed. 

Seems that the steam mains run along both sides of the house and have dry returns that parallel the mains that feed the reservoir/pump.  Not which rads feed into the gravity return lines that come front to back of the house midline.  They get hot pretty early on in the cycle....the Webster thermostatic traps on those returns make me think the wet return carries steam but not sure why.  

Would be great to have someone look at the system in detail if possible.  Crawl space is pretty tight, but can go in to take some more pix ...

Steamhead

Whoever installed that boiler should not be in the business. Post the model number- should be EG- or PEG-something, and we can tell you how it should be piped.

HansL

EGH-85

Steamhead

This boiler requires a 3-inch header, though you can get away with 2" risers from the boiler to the header. Piping diagram is on page 17 of the manual, here:

https://www.weil-mclain.com/sites/default/files/field-file/EGH Boiler Manual.pdf

Also, the steam takeoff from the header does not belong between the risers from the boiler. And, the header must be 24" above the highest possible water level in the boiler.

Your present piping is undoubtedly not able to separate the steam from any water that may be coming up from the boiler. This results in "wet steam" and reduced efficiency.

HansL

Thanks for the insights!  I wonder if the boiler was replaced without re-plumbing the system or if the installer was just incompetent?

Would you recommend redoing the plumbing or waiting a few years until the boiler needs replacing?  Both seem like big projects...

any thoughts on the return plumbing?

I see you’re in Baltimore...we moved to NC a couple years ago from Belt St in Riverside/Locust Point.  We miss that place a lot

thanks

Jamie Hall

Indeed the boiler piping is dreadful. But I'm still trying to piece together in my mind the rest of the system. For instance -- the two big Warren Webster traps you picture. You say they go from the gravity line to the dry return which goes to the pump. I would usually think of those as crossover traps -- but that would mean they went from a steam main to what was originally a dry return. I can't think of any reason at all why someone would have connected them between a dry return and a wet return.

I really do need a sketch of this thing. I'm beginning to wonder if it might not have been a vapour system at one point, and got thoroughly knuckleheaded over the years.

HansL

Hi Jamie-

Here is my best attempt at a sketch. Pretty bad, but hopefully you can interpret. Based on your comment about crossover traps, I looked up some schematics of vapor systems from Dan Holohan’s book and I think you are probably right. After crawling around in the crawl, I am pretty sure that what I was referring to as dry returns are really just the end of the steam main(s) that come into the basement 2.5’ above the water line....have ascending pipe to Webster 512 “crossover” traps and drop at 90° into a wet line that runs along the basement floor perimeter to the loop. One of the steam mains running down the center of the crawl has 3 big patches clamped on it and is still leaking and rusted out. Pitch on a lot of the pipes down there looks questionable....

I also included sketches of the 1st and 2nd floors with radiators in red....not really sure how the steam and returns are piped up there.

This seams like a lot of wet line for just returning condensate from the end of the main....is it needed? Any chance of restoring this back to a vapor system (if that is indeed the original form)?

I also have a few photos from my trip into the bowels of the crawl space if those would be helpful, but didn’t want to overwhelm.


Thanks!

Steamhead

HansL said:

Thanks for the insights!  I wonder if the boiler was replaced without re-plumbing the system or if the installer was just incompetent?

Would you recommend redoing the plumbing or waiting a few years until the boiler needs replacing?  Both seem like big projects...

any thoughts on the return plumbing?

I see you’re in Baltimore...we moved to NC a couple years ago from Belt St in Riverside/Locust Point.  We miss that place a lot

thanks

That boiler looks fairly new. I'd get it repiped, and do it in such a way that if the boiler dies, the header won't have to be replaced.

Many folks are leaving Baltimore these days- really can't blame them.

HansL

Steamhead said:

That boiler looks fairly new. I'd get it repiped, and do it in such a way that if the boiler dies, the header won't have to be replaced. Many folks are leaving Baltimore these days- really can't blame them.

Thanks.  Boiler was apparently installed in 2003

Jamie Hall

Are those two steam mains joined to each other at the location where the crossover traps are? They shouldn't be.

If those two crossover traps are working, and if the pipe going on from there and dropping to the condensate reservoir can breath freely, that is a workable system. Not quite the way I'd have done it, but it will work.

Now that said, you do need to have traps on the outlets to the radiators. Any hope of a picture or two of the radiator inlets and outlets?

HansL

Jamie Hall said:

Are those two steam mains joined to each other at the location where the crossover traps are? They shouldn't be.

They join below the waterline (at basement floor).

I put Tunstall capsules in both “crossover” traps and they seem to close in steam (hot on steam side and cool on condensate side), but have not verified that they are open for condensate and air.

HansL

Jamie Hall said:

Not quite the way I'd have done it, but it will work. Now that said, you do need to have traps on the outlets to the radiators. Any hope of a picture or two of the radiator inlets and outlets?

How would you have done the end of main plumbing?  Since I need to have the leaking/rusted sections replaced anyway, wonder if I should have it redone in a different configuration? Or if we are pretty much wed to the weird “crossover” trap situation without major plumbing.

Do you want pix of inlet/outlets from the crawl or valve and thermostatic trap at each radiator?  The latter is easy, but have some crawl space plumbing pix.

Jamie Hall

Well let's see here. I don't think there's any need to redo the end of main plumbing. It's just a little... different, shall we say. But it should work fine just the way it is.

It's actually not that weird, in some ways -- all that happened was that for some reason the steam mains got extended over to that location, rather than extending the dry returns. Quite likely because it was much easier to do...

I have a distaste for boiler feed pumps. In general. Therefore, the change I would at least contemplate is taking that dry return over to the boiler -- as it does, after a fashion -- making sure it was at least 3 feet above the boiler water line. Then I would put two or three Gorton #2 vents on it at that point, then I would drop it right down to the existing wet return and into the boiler, eliminating the feed tank and the pump completely.

Then I would go around to the other side of the boiler and put on a vapourstat and set it for no more than 14 ounces per square inch to start with, and turn it down as I could to find a good pressure to run the system at.

Don't need a lot of pictures, but ones of a representative radiator outlet arrangement and inlet valves would be mighty useful.

HansL

Thank you for the advice. I will try to find a good plumber in my area before doing any of the major re-plumbing of the near boiler or return, but definitely like the idea of getting rid of the pump and reservoir.

I have attached a revised drawing that includes a few details such as what appears to be plumbing to risers and 1st floor radiators. I have numbered the radiators and included a few pictures of valves and steam traps. Only 2 of the 11 radiators (#1 and #7) have steam valve near the top and the rest are at the floor....not sure how these were "originally" configured, but wonder if this gives any indication of whether it was a vapor system? also, with a low pressure steam system is there any functional difference between valve on top or bottom?

Traps are a hodge podge, although most are Warren Webster 512HB traps. I still have a few traps to repair, but most are now Tunstall capsules.



Here are some photos:

#1




#2




#3




#4




#5



#6




#7



#8




#9




#10




#11



I will also add some pictures from the crawlspace later. There are a lot of broken hangers and suspect that pitch is a major issue in the mains and returns....here is a sneak peak.

EBEBRATT-Ed

Poor boiler doesn't have a chance with that "header" 24" above the water line.......not

HansL

What would you recommend? do you think this should be a drop header? I haven't been able to find any pix of near boiler plumbing like mine, so other than totally starting from scratch, I don't know what to do...
Thanks

SteamCoffee

One pipe radiators?

HansL

Also wonder if anyone knows the manufacturer of my radiator #1?

HansL

SteamCoffee said:

One pipe radiators?

Are you suggesting converting the system to 1-pipe and getting rid of the return system altogether?

ethicalpaul

HansL said:

What would you recommend? do you think this should be a drop header? I haven't been able to find any pix of near boiler plumbing like mine, so other than totally starting from scratch, I don't know what to do...
Thanks

It can't really be a drop header because there's no where for the risers to drop to since they are about 1" high.

It needs to be repiped at the boiler following the installation manual. It's a very straightforward job for a qualified contractor. Even some homeowners can manage it. But you have to find someone who knows steam, or at least will be willing to look at the manual. Try the "Find a Contractor" link on the home page of this site.

Steamhead

HansL said:

Also wonder if anyone knows the manufacturer of my radiator #1?

That looks like a standard wall radiator. Pretty much every radiator manufacturer had something like that, including American Radiator Co. which made those lovely Rococo radiators.

ISTR most Vapor system manufacturers were able to upgrade existing systems to Vapor, even if they were using steam-type radiators such as these Rococos.

HansL

Try the "Find a Contractor" link on the home page of this site.

Nothing comes up within the 100 mile cut off =(

ethicalpaul

OK well that's not great, but you could have your contractor make a proposal and you could ask him to show you in the installation manual the diagram that he will follow. We can help with any questions that might come up after that.

SteamCoffee

HansL said:

SteamCoffee said:

One pipe radiators?

Are you suggesting converting the system to 1-pipe and getting rid of the return system altogether?

no....but a vapor system working off 1 pipe radiators.....you need 2 pipe or HW radiators...