Combining One and Two Pipe Steam Systems

New England SteamWorks

A beautiful old house:


Fell on hard times, but is now to be resurrected as a Bed & Breakfast. Hasn't been heated in a few decades, and the copper thieves got in.



Interestingly, it has two boilers, though it has always been a single-family home. One boiler feeds a Dunham 2-pipe system for all the radiators on the 2nd floor and one on the 1st, while the other boiler is a conventional single pipe that handles 1st and 3rd floors.

To simplify things I'd like to pipe it with a single boiler. I am thinking a header off the boiler with two risers dropping into two additional headers, one for each system. Any one have any experience doing this with perhaps words of wisdom to pass along? Or perhaps a reason why I shouldn't combine them?



Thanks guys.

Jamie Hall

The only gotcha that I can think of off hand is that balancing may be a bit tedious. Get the mains well vented, though, and I imagine that you can get there without problems.

Steamhead

Well, that's what happens when you pipe steam boilers in copper. And I bet those Dunkirk boilers were bushed down from 2-1/2" at the steam outlet to 2".

Why not leave them separated, so you'll have at least some zoning?

New England SteamWorks

Steamhead said:

Why not leave them separated, so you'll have at least some zoning?

Well, they are very cost conscious. It's going to take a lot of dough to bring this house back. I haven't done any numbers yet, but the two boilers are going to be more of course, and efficiency-wise a single boiler would be nice. But as @Jamie Hall commented, balancing will be a bit trickier. I guess the question is: how much trickier? And that is an unknown.

Lots of the radiators are missing, or not connected, or need to be moved however, so there is a an opportunity there to balance with the actual radiators, which is not normally present. Lots of walls are open right now.

EBEBRATT-Ed

If the owners are "cost conscious" this may not be the house for them. I am sure it would work better with two boilers. One boiler may be a can of worms.

With all the water lines and plumbing ripped out I am sure they would like to save money on the heating system. This isn't the type of house or system that will respond well to that.
Just MHO

Ironman

My two cents worth:
I would be very concerned about balancing. You may seem to have it right in milder weather, only to find it gets out of whack when it gets colder.

Jamie, Frank and Ed all share that concern and they're more knowledgeable on steam than I am. There's a reason there were two boilers and I'd weigh that very heavily against trying to marry the two systems to one.

From a business standpoint, I'd look at it this way: why would I wanna expose myself and my business to the liability of it not working properly so I could cut myself out of some work and income in order to save them some $$?? You must surely realize than any issues that arise from doing it with one boiler will totally be your liability and they will expect you to correct them at your expense. They will insist that you are the expert and you should have known that one boiler wouldn't work right. Unfortunately, a judge will see it that way too should it end up there.

'Cost conscience"? That's just a fancy name for a tightwad. And those are always the very kind that will try to whittle your price down while at the same time expecting to get the value they cut out.

JUGHNE

I have a schoolhouse with a 1 pipe and also 2 pipe. Zone valves control each. (2 tstats) 1 pipe is CI rads....2 pipe is steel convectors. Just the first issue.

The 1 pipe is 3 story 1919 building. 2 pipe is single level 1955.
One 1,000,000 btu plus boiler tries to do both. Heat load has dropped in both buildings because of envelope upgrades. So we have a boiler twice the size of connected EDR as many 1 pipe rads were literally thrown off the fire escape. Most of the 2 pipe EDR is still connected but throttled down with valves and orifices.

3 story single pipe system is on northwest corner. 2 pipe system is on south east corner with build around additons. Solar gain and wind varies loads so that often only one zone calls. Grossly over sized boiler short cycles constantly. ((even if matched total building EDR it still would short cycle)). For this particular school house building, if possible I would most certainly go for the 2 boilers....correctly sized....the 1 pipe could be gravity return....the 2 pipe must be cond or feeder pumped.
I have designed, drawn and even priced this out as just a desk exercise. The school board is looking at a complete redo with something that I am sure will not be steam......just don't get me started....

Now the B&B's I am familiar with have the first floor mostly as a commons area, this would need good temp all winter.
The upper floor rooms may not be near 100% occupancy all winter long....depends upon the demand.
It seems that separate TRV's on a 2 pipe system would fit the bill for those areas.

Sitting at my desk thinking about spending/saving other people money.....I would connect the first floor to one boiler...one Tstat.

The 2nd and 3rd floor to another boiler with 2 pipe system, if at all possible, with TRV's on each rad.

Consider 2 stage burners for each boiler.
Again other people's money up front but think about empty rooms not needing heat in the future and long term savings.

If the bathrooms stack above each other I would put those on the main floor system with TRV in each bath....freeze protection provided by the main floor system and you could almost shut the 2nd & 3rd floor off.

Does it seem odd that the "better" heating system does the 2nd floor which is between a heated 1st and 3rd floor?

New England SteamWorks

My thought process is thus: The first floor is 1-pipe so it will be what it will be, one boiler or two. That's where the thermostat will be. The 2nd floor is 2-pipe so it can be throttled as needed unless it's too cold (which is highly unlikely on the 2nd floor). And that leaves the third floor, which is never too cold in any steam heated home I've see. Likely too warm. Does an extra boiler mitigate that?

I don't think they're tightwads. They just have a Bed & Breakfast to get off the ground, and then they have to deal with ongoing operational expenses.

gerry gill

My two cents-I've noticed over the years, that on one pipe steam systems, the second floors tend to overheat in a really cold weather when the heated air on the first floor rises up the staircase and adds to the heat of the second-floor radiators. Who knows what went through the mind of the person who designed the system, but maybe they wanted control of the radiators on the second floor. The third floor was probably for the servants, so well, who cared.
I would recommend keeping two separate boilers, in order to have the ability to run two separate pressures, which may be necessary.
The Dunham system was probably a vapor vacuum system and one pipe probably ran a pound and a half. The one pipe probably can run at lower pressure. But can it run in vapor effectively? Maybe maybe not. But the Dunham system side didn't have a boiler return trap in the picture so I'm suspecting that Iran at very low pressure.
Anyways that's my thoughts on it. Hope it helps.

New England SteamWorks

As always, your feedback is invaluable.

I am thinking this is the system:

gerry gill

i think your correct.

New England SteamWorks

JUGHNE said:

Does it seem odd that the "better" heating system does the 2nd floor which is between a heated 1st and 3rd floor?

Yes. I'd feel a lot better about this decision if I understood why the system came to be 1-pipe on 1st and 3rd floors, and 2-pipe on the 2nd. Would enjoy any and all hypothesis.

New England SteamWorks

In my heart of hearts, and given the fact that there's a boiler pit in the basement, I thought there was a really good chance to run them both with a single boiler. I was relishing the challenge actually. But that would be playing with other peoples money, and ignoring the collective wisdom of this board. So after much contemplation:

It shall be two boilers. MegaSteams, of course!

New England SteamWorks

The Past & The Pit:

New England SteamWorks

The Future:

jumper

Two pipe with TRVs automatically balance. Why mess around with stuff that hasn't worked in decades? I'd chuck the rads and install steel panels. I'd repipe with insulated flex. Little individual ones from a central manifold like the radiant hydronics guys do. Way less work than dead men's fittings. Single point air evacuation. Maybe you can rehabilitate the ancient one already there? Search "Igor" on this site.

As for how the old system came to be? Probably original one pipe was unsatisfactory. So I presume the Dunham was installed where comfort was important. Are the one pipe rads one pipe steam radiators?

Danny Scully

@jumper, thanks for the laugh!

ChrisJ

Please keep us posted @New England SteamWorks

AMservices

I'm jealous. I wish I had a project where I could play with a 1 pipe and a 2 pipe system. You know I'd be all over installing a vacuum pump to decrease pickup losses and help balance the system.

New England SteamWorks

Unfortunately, before TRVs and vacuum pumps the boilers first need to somehow find their way into the pit. Each MegaSteam is nearly 900lbs. Complicating things, a small addition was thoughtlessly added a few decades ago, blocking any hope of a direct dolly shot at the steps:



As you can see, no room to make a turn. Time for the A Frame and come-along:



It was a long and arduous process, getting not one, but two boilers down. No fun at all, not to mention blowing budgeted labor hours right out of the water.

But in the end, -mad, hot, and exhausted, -the boilers came to rest in the pit. Wouldn't care to ever do it again...



But, I probably will.

Just not right away!

Ironman

Looking forward to seeing how it turns out. I'm sure you'll post pics.

New England SteamWorks

I've been in a bit of a rut lately trying to find a good helper. You know how it is: When you have to tell them to put down the phone and pick up the pipe wrench?

Well, on this job I decided to use Ilka as my helper. But I guess she is the same generation...

When I told her to put down her bone and pick up the pipe wrench, I got the same reaction:

BobC

Matybe if your pipe wrenches had padding on them?

Bob

Ironman

New England SteamWorks said:

I've been in a bit of a rut lately trying to find a good helper. You know how it is: When you have to tell them to put down the phone and pick up the pipe wrench?

Well, on this job I decided to use Ilka as my helper. But I guess she is the same generation...

When I told her to put down her bone and pick up the pipe wrench, I got the same reaction:

I tell them when they're hired that there will be absolutely no cell phone useage that doesn't relate to work on my dime. They can do it on break or lunch time. If they do it once, they get warned; if they do it twice, they get fired!

ChrisJ

Ironman said:

New England SteamWorks said:

I've been in a bit of a rut lately trying to find a good helper. You know how it is: When you have to tell them to put down the phone and pick up the pipe wrench?

Well, on this job I decided to use Ilka as my helper. But I guess she is the same generation...

When I told her to put down her bone and pick up the pipe wrench, I got the same reaction:

I tell them when they're hired that there will be absolutely no cell phone useage that doesn't relate to work on my dime. They can do it on break or lunch time. If they do it once, they get warned; if they do it twice, they get fired!

What about when a worker gets an emergency call, perhaps wife giving birth, death in the family. Do you skip the warning under such conditions?

Ironman

Of course. I'm actually one of the nicest guys you could work for. The're just some forms of nonsense that I don't tolerate and paying someone to goof off on a cell phone while I'm working and expecting their help is one of them.

JUGHNE

Our high school admin & board are discussion a policy of not allowing cell phones in school. I asked the grandson if kids are texting all the time during class. He said most of the texts come from the parents to student???
So I can see a battle for the school.
But also see where this phone in hand comes from.
It takes one hand to hold/carry the phone and limits ability to do anything. IMO....from old grumpy guy when it comes to this subject.

jumper

Good workers go into business for themselves too often.

Danny Scully

Where is the 2-pipe rad located on the first floor?

New England SteamWorks

Making progress. First time I ever installed boilers with no running water, electricity, or fuel. But, we'll get there. It's been decades after all...






In the main hallway Danny.

Danny Scully

No chance it once was a B&B?

New England SteamWorks

Danny Scully said:

No chance it once was a B&B?

No. History very well, and quite extensively, documented.

Danny Scully

Looks awesome!

newagedawn

very nice, i get so happy when someone restores the past regardless of the obstacles, well done, cheers !!!!!

jumper

Can I presume the old rads & pipes checked out okay?

New England SteamWorks

jumper said:

Can I presume the old rads & pipes checked out okay?

You may not!

A long way to go on this one yet. This was just Phase One. Boilers not yet fired because no water, no electricity, no oil, and no (safe) chimney.

We already know lots of pipes and rads are dysfunctional just from looking. Years ago the building received a grant to shore up the tower, which was beginning to lean like Pisa. They did a good job, but unfortunately my steam pipes where in their way, so they just cut them out...

Plus, with the conversion to a B&B, rads need to go where they are not currently.

Lots of work yet...

jumper

New England SteamWorks said:

jumper said:

Can I presume the old rads & pipes checked out okay?

You may not!

A long way to go on this one yet. This was just Phase One. Boilers not yet fired because no water, no electricity, no oil, and no (safe) chimney.

We already know lots of pipes and rads are dysfunctional just from looking. Years ago the building received a grant to shore up the tower, which was beginning to lean like Pisa. They did a good job, but unfortunately my steam pipes where in their way, so they just cut them out...

Plus, with the conversion to a B&B, rads need to go where they are not currently.

Lots of work yet...

That is why I suggested that:>>Two pipe with TRVs automatically balance. Why mess around with stuff that hasn't worked in decades? I'd chuck the rads and install steel panels. I'd repipe with insulated flex. Little individual ones from a central manifold like the radiant hydronics guys do. Way less work than dead men's fittings. Single point air evacuation. Maybe you can rehabilitate the ancient one already there? Search "Igor" on this site.<<

Unless you enjoy working on very old radiators?

New England SteamWorks

jumper said:

Unless you enjoy working on very old radiators?

Actually, I do.

Also, it hasn't worked in decades because the home wasn't occupied. The system might work just fine, for all we know, once the piping repairs are completed. We'd all like to find out.

Lastly, it's being restored with loving care and historic tax credits. Everyone, including myself, wants it brought back as close to original as possible.

That's Plan A anyway...

Danny Scully

I can't tell if @jumper is just busting chops, or if he's serious. It's certainly comical to me Keep up the good work @New England SteamWorks!

jumper

Danny Scully said:

I can't tell if @jumper is just busting chops, or if he's serious. It's certainly comical to me Keep up the good work @New England SteamWorks!

I'm serious,Dan. Nobody restores a Model T for their primary transportation. So much work with no idea how satisfactory that restored 100 year old will be?

Danny Scully

@jumper, steam systems are more commonly referred to as cadillacs around here and in regards to the unknown idea of satisfactory, no guts, no glory!