One-Pipe Steam – Radiator Sizing and Removal During First-Floor Renovation

steamboilernovice

We are getting ready to start a major first-floor renovation of our 1856 home and would appreciate some advice on radiator sizing and potentially removing/replacing a couple of radiators from our one-pipe steam system.

I've attached two floor plans showing the existing and proposed layouts, with the radiators numbered for reference.

Current Steam System:

• Boiler: Utica PEG187EID gas-fired steam boiler
• Boiler rating: 488 sq. ft. steam (488 EDR)
• One-pipe steam system
• 14 radiators throughout the house
• Total connected radiation: Approximately 500 EDR

Radiators Affected by Renovation:

Radiator	Existing EDR	Proposed EDR
#1 – Old Kitchen	60 (4 tube cast iron)	40 New
#2 – Old Dining Room	30 (2 column cast iron)	30 Leave
#3 – Sunken living room	40 (Tuttle & Bailey fin-tube convector)	Remove?
#4 – Sunken living room	32 (American Radiator ARCO Convector Unit #533)	32 Leave
Old bathroom	15 (3 tube cast iron)	Remove

If we make all these changes, we would reduce the total connected radiation by approximately 75 EDR, from 500 to 425 EDR. Assuming the convector EDR's are accurate.

Renovation Details:

The kitchen will be approximately 298 sq. ft., with an adjoining mudroom area of approximately 100 sq. ft. Radiator #1 will be reduced from 60 to approximately 40 EDR and will be intended to heat the mudroom area while also contributing heat to the kitchen. The existing kitchen has zero insulation in the walls and does ok in extreme cold, but will be fully insulated and opened up.

Radiator #2 (30 EDR) will remain.

The sunken living room is approximately 175 sq. ft. and has two exterior walls with several windows and zero ceiling insulation currently. We are opening up the wall between the new kitchen and sunken room, leaving a partial 36-inch-high half wall.

Radiator #4 (32 EDR) will remain in the sunken room. We would ideally like to eliminate radiator #3 (40 EDR) to accommodate the new layout or leave/replace it. It will not be in the way with a half wall.

We are also eliminating the existing bathroom radiator (approximately 15 EDR), as the new bathroom will have electric radiant floor heating.

The renovation will take all the rooms down to the studs and properly insulate the exterior walls and ceilings, which currently have little or no insulation. All the windows have been replaced with new windows.

The ceilings are about 7'2" in the house.

My Questions:

1. Radiator #1: Would approximately 40 EDR be sufficient for the new kitchen/mudroom arrangement, considering the more open layout and nearby radiators?
2. Radiator #3: With the wall opened between the kitchen and sunken living room, would the remaining 32 EDR radiator (#4), along with heat from adjoining spaces, likely be sufficient for the sunken room? Or should we be concerned about eliminating the 40 EDR radiator? Another option would be a smaller cast iron wall hung or thin radiator in the space. Or keep the convector built into the wall.
3. Boiler Sizing: Our Utica PEG187EID is rated at 488 EDR, which is fairly close to our current connected radiation of approximately 500 EDR. If we reduce the connected radiation to approximately 425 EDR, the boiler would be about 15% oversized relative to the remaining radiation. Is that a significant concern for a one-pipe steam system? Would we be creating potential short-cycling or balancing issues?
4. Overall System: Is there anything else we should consider when removing this much radiation from an existing steam system? We plan to have the unused radiator connections properly disconnected and capped.

Our preference is to eliminate the unnecessary radiators where possible, but not at the expense of comfort or proper steam system operation.

Thanks in advance for any advice!

Steam Renovation Layout.pdf

Jamie Hall

Have you consulted a structural engineer on your plans? You may have proposed deleting a bearing wall — or, depending on exactly when and how the house was built, at least encountering a major beam and post. In fact, I would assume that any wall is a bearing wall, unless examined and proven otherwise.

Is the sunken living room currently sunken, or are you planning on lowering this floor level? If you are lowering it, I can almost guarantee that you are going to have "interesting" structural problems.

Also, you mention taking the exterior wall "down to studs". Again, depending on exactly when this house was built, it may not HAVE studs in any conventional sense.

1856 is a bit late for full post and beam construction, but that would still not have been uncommon. Even if this is a more conventionally framed house, be aware that stud and joist spacings will not be modern standard, and timber sizes will also not be modern standard Further, some timbers (particularly joists) may appear to be undersized by modern standards, and may or may not pass code inspection in your area.

dabrakeman

I don't think 15% oversized would be a problem and you can balance it out as conditions merit but I would err on the side of leaving rather than removing radiators since there is little benefit of reducing standing radiation if leaving the same assumedly working boiler. If a room is a bit warm slow down the radiator or add a TRV. Bathroom radiator would obviously go but why go through the trouble of swapping a 60 edr for 40 edr if you can just slow it down. If any drafts remain in the house they will end up at the floor of the sunken living room…

steamboilernovice

https://forum.heatinghelp.com/discussion/comment/1906634#Comment_1906634

Thanks for your concerns. The structural aspects are being addressed as part of the renovation. I'm primarily looking for feedback on the steam heating and proposed radiator changes. Any thoughts on those would be appreciated.

steamboilernovice

https://forum.heatinghelp.com/discussion/comment/1906640#Comment_1906640

Thanks. The replacement of the kitchen radiator is due to its length. We will need a shorter/taller radiator.

Jamie Hall

https://forum.heatinghelp.com/discussion/comment/1906645#Comment_1906645

I only bring it up because that is one of my areas of professional engineering licensing — and I have seen too many catastrophes in working on pre-1890 structures to not be concerned.

Grallert

Kitchens are always hard. We want more cabinet and counter space and radiators are in the way. I would suggest electric radiant in the floor. Under what I might assume will be tile? Same goes for bathrooms.