Can Williamson-Thermoflo steam boiler (GSA-125-N-IP) be converted/used for hot water system?

mosswald

Hi folks,
I'm going to completely rehab a 1909 small 1050 sqft 2-story in NW Ohio, and I want to know if my Williamson-Thermoflo's GSA gas fired steam boiler (GSA-125-N-IP) can be utilized in a hot water system setup.

Context: A big thing in this redo is removing a central chimney which will open up the floor plan on both floors and make the home usable (another bath, 2 bedrooms vs. one, a "normal" main room).

The home has a 1-pipe steam radiator system serving 6 radiators, and the current boiler position vents into the chimney, making the whole project dependent on moving this so I can vent out a side wall (plus adjusting 1-2 radiators positions). Which likely moves EVERYTHING in the basement.

Does anyone know the answer off hand? I've seen many comments that it can be done, but specifically with this boiler is my question. Before I think any further on options and any other issues, I wanted to get some input. Thanks in advance!

nicholas bonham-carter

Modulating-condensing boilers can certainly be vented out a side wall, but your present boiler would need to have a new chimney rising above the roof.
In addition, the radiators (rated for steam), will give off less heat, when used for hot water, so will they be big enough?
it would be better to find a new route for a new flue, and keep the steam, as it probably only needs a 8-10 inch vent.--NBC

Steamhead

It is possible to use sidewall venting on a steam system. You do NOT have to incur the additional risk and expense of switching to hot-water to do it.

If you're looking at sidewall venting, you need to determine whether you have enough height above the highest snowfall accumulation in that area. You don't want snow to block the vent.

Also, such a vent needs to be a certain distance from windows, doors and other wall penetrations. Check the Codes in your area to see what they require.

A power venter could be used with that boiler, but you need to realize that this will introduce more complication and possibly more service calls. There's a reason chimneys are so popular- they have no moving parts.

If you're doing an extensive renovation, find a way to put an all-fuel chimney in a different location. This will keep things simple. You might be able to pipe the steam from the new location to the old and tie onto the existing piping fairly easily. Post some diagrams so we can see where everything is and what you have in mind.

mosswald

Appreciate the comments! I'm going to see about relocating first, I'll have to diagram this out in the next week or so. Thanks!

mosswald

So, a follow up – can THIS boiler be modified to serve hot water? I read that "removing the low water cutoff, pressuretrol and relief valve and installing a new boiler high limit control, 30# relief valve, circulator pump and all necessary hydronic accessories..." would be a potential direction for most "modern steam boilers" (HydronicAlternatives.com).

I wonder about this option because I read that THIS boiler has to have an all-fuel chimney, but if it turns out that moving the boiler also makes it such that the piping can't tie into the old location (not sure yet), then I'd like to consider a switch to PEX-AL-PEX and hot water, thus hiding the pipes (upstairs pipes exposed on main floor), allowing radiators to move, and making it clearer/cleaner to me. I did some sizing of my radiators and it seems they will be more than OK for hot water, given that I'm also insulating.

Thanks for any reply!

SWEI

That boiler is at least three (possibly as much as five) times larger than what you need to heat that house on the coldest day of the year.

By the time you re-trim the boiler, buy a power venter, and add enough buffer capacity to deal with the oversizing, you will spend more than you would buying a new, properly sized boiler.

Or you could just keep the steam...

Steamhead

mosswald said:

if it turns out that moving the boiler also makes it such that the piping can't tie into the old location (not sure yet), then I'd like to consider a switch to PEX-AL-PEX and hot water, thus hiding the pipes (upstairs pipes exposed on main floor),

Two things here:

First, those old steam and hot-water pipes were run inside the room to make sure any heat lost would stay in the house, and (in the case of hot-water) to keep them from freezing. A lot of people have found out the hard way this winter, that running pipes in outside walls is NOT a good idea.

Second, it's probably easier to tie a relocated steam boiler to the existing piping than most non-steam contractors would have you believe. We'll know for sure when we see your diagrams.

vaporvac

Some pics of the current boiler set up, near boiler piping and a representative rad would help. Also, be aware that rads were generally placed where they were for a reason...to help with convection. Moving them may affect this and resul in less apparent heat.

mosswald

UPDATE: Sad news for steamheads: I'm scrapping the whole system, and selling the boiler. HOWEVER, through your suggestions and help I did determine that I would be able to move the boiler, and I was glad to spend some time to learn how these systems work.

Once I drew it all out it from pictures and measures, it became completely obvious that it was a typical construction, just like all the old-time drawings show. That was cool to feel the lightbulb go off in my head! We really were interested in keeping the steam or radiators, and believe in it over air, but it's just not right for this place and time.

Other notes:

1. I'm flipping the house, and I'm sure AC is what people want when buying a virtually new home.
   
2. I wouldn't be able to really test it, since it's not heating season and I want to sell before fall.
   
3. The boiler is oversized, will be even more oversized, can't switch to hot water, must have a big chimney.
   
4. HVAC air doesn't need complex venting.
   

Thanks again for your suggestions and comments, folks!

JStar

If you thought the idea of relocating an exhaust vent and some steam pipe was troublesome, wait until you have to deal with properly sized ductwork.

KC_Jones

JStar said:

If you thought the idea of relocating an exhaust vent and some steam pipe was troublesome, wait until you have to deal with properly sized ductwork.

Not to mention the cost of doing it PROPERLY. And you plan to do all this, flip the house and make money? Did you get the house for free? I wish you best of luck with your project.

JStar

If ductwork doesn't take up a lot of space, it probably isn't sized or installed correctly.

vaporvac

Why not just put in Spacepak or something of that ilk for AC?That's the elegant and correct solution. Even minisplits would be better. My personal experience is that most houses installed with steam NEED it to keep the house warm. I used to redo houses for a living (before the horrible term flipper), but would never have considered this correct or worthwhile. There's certainly time to test it, even in the summer. It may not be optimal, but it's only a matter of setting the Tstat high enough to get steam to the rads.
HVAC requires a LOT of BIG ducting for supplies AND returns from every room to work at all well. That's a lot of space in the basement AND rooms. Of course, if done incorrectly, you won't have to live there and enjoy the pleasure of rooms that neither heat nor cool well.
It's nice that you asked, but I can't believe anyone considers ripping out an entire heating system for an inferior one. It boggles my mind. I need to stop now. C-

ChrisJ

mosswald said:

UPDATE: Sad news for steamheads: I'm scrapping the whole system, and selling the boiler. HOWEVER, through your suggestions and help I did determine that I would be able to move the boiler, and I was glad to spend some time to learn how these systems work.

Once I drew it all out it from pictures and measures, it became completely obvious that it was a typical construction, just like all the old-time drawings show. That was cool to feel the lightbulb go off in my head! We really were interested in keeping the steam or radiators, and believe in it over air, but it's just not right for this place and time.

Other notes:

1. I'm flipping the house, and I'm sure AC is what people want when buying a virtually new home.
   
2. I wouldn't be able to really test it, since it's not heating season and I want to sell before fall.
   
3. The boiler is oversized, will be even more oversized, can't switch to hot water, must have a big chimney.
   
4. HVAC air doesn't need complex venting.
   

Thanks again for your suggestions and comments, folks!

If you learned how these systems work you wouldn't be scrapping it.
And believe me, it's not a sad day for steamheads, it's a sad day for whoever is going to live in that house.

Steamhead

I would have loved to be a fly on the wall and hear the conversations with whoever he was working with................ willing to bet they absolutely refused to work with the steam.

Brewbeer

I'm scrapping my forced air system with AC and installing hot water baseboard, in part because the ductwork is so badly done that it needs to be entirely redone.