Sizing radiators in a 2200 sq ft colonial/victorian

davemascera · October 4

Hi all, I have a house in NJ that was built in the 1700's and caught fire then purchased by a rich family who added on an early victorian (and a cast iron steam system!).

I've had a lot done, but we're now moved out doing complete renovation to shore up some lead paint and nip any other deterioration at the bud.

Basically, we have a Weil-McLain 175k BTU boiler and this house is about 2200sqft… some of the exterior is insulated with fiberglass, some with just crappy cellulose that i presume does nothing. Lots of the original lime plaster exists but in two bigger rooms we got asbestos rock lathe + blue board and plaster (1.75" thick walls).

I had the asbestos insulation removed from the pipes and never replaced it. Wasn't sure if I need to put something else around. Some rooms are literally hot as hell, some radiators don't heat up at all whether or not you replace the vents (is it possible for a cast iron radiator to be clogged??).

Regardless, I've been changing out angles and spuds myself (and getting these puppies painted) one at a time til now when I wanna do the last 8 at once.

I'm reading "the lost art of steam heat" by the dude who owns this website, and it seems like the "people kept the windows open at night" bit is totally true here: bedroom radiators are gigantic and seem impossible to control unless I wanna get awoken at 5 am by the sun cause curtains are drawn.

But reasoning seems to be inconsistent. Seems like the radiators should match the room and should have nothing to do with the remaining pressure at that point in the system no? I have a pretty small room with the same no. of windows to other rooms (but there is an ext door), where there's a 48" rad!

But other much larger rooms have much smaller ones, like <36"? When temp gets down to like 0ºF or below, system cranks up to like 5 PSI and some of the patches on my pipes spray steam (plus main vent and weird other vent that I dont understand spray water). System makes a few knocks here and there but overall is relatively quiet.

I talked to some heating guys and most of them are just like replace the return (which i'm sure is valid advice to a small extent) or your boiler is old. They don't seem to know the information in the book and are scared to change radiator sizes. Hard for me to know, seems impossible to find someone who is really educated on these systems/respects them.

I just don't wanna refurb/paint 8 cast iron radiators only to find they are too big or small for the rooms they'll be in. Anyone have any broad or specific advice?

Jamie Hall · October 4

Sounds a lot like someone, sometime, got creative and just started moving radiators around. You are quite right that the radiator size — and hence output — should more or less match the heat loss from the room.

However, that may be only part of your problem. You say that some of the radiators are really hot, and some hardly heat at all. You also mention vents, which suggests that you have a one pipe steam system. Which, combined, suggests very much that the main venting and steam mains need a lot of attention.

May I suggest fining out if @EzzyT or @clammy work in your area? they are top notch steam guys.

Now. You mention insulation and lime plaster and all that. I am probably too late to the party, but there are no modern materials which are equal to, never mind superior to,the materials you mention. Kepp them if at all possible. Likewise the windows.

ethicalpaul · October 4

If vents are ever spraying water, it is likely due to "surging" where boiler water is "thrown" up into the mains. This can be due to water quality, poor piping near the boiler, or both. This will typically be accompanied by the water level in the gauge glass dramatically dropping.

This can also prevent steam from flowing evenly through your system.

Also as indicated above, someone could have done something wrong such as leave a place in the piping where water can sit..this can also prevent steam from reaching one or more radiators. House settling can also cause this.

It is almost certainly not a clog in a radiator or radiator supply pipe.

PS: your pressure control should be set to never allow the system pressure to go above 1.5 PSI.

AdmiralYoda · October 4

Sounds like a fun project! Way back in the day the radiators were indeed much larger than we would need now in an insulated house. Zero insulation, plenty of drafts, bad or open windows. In an ideal world with a renovated home you would run a heat loss calculation on a room and size the radiator accordingly.

You can do the same now if you are remodeling and insulating. Run the heat loss calculations and mix-and-match your existing radiators to match each room as best you can. Not a bad time to consider purchasing a few new radiators if you really want to dial the system in.

That brings up a couple other points though. Your system doesn't sound really well balanced. Fiberglass pipe insulation helps and choosing different radiator vents can slow down or speed up some radiators. How is your main venting situation? What pressures are you running at? How is the near boiler piping?

The next step down the line for rooms that get too hot would be TRV's, Thermostatic Radiator Vents. They have a dial that you can set so the valve closes at a certain temperature, effectively turning the radiator off and not letting it get much hotter.

delcrossv · October 4

Agree with Jamie. As a start, move the big radiators to the big rooms, and the smaller ones to the smaller ones.

You clearly have issues with your mains. Fix those and a lot of issues will go away. After fixing the piping, insulate EVERYTHING.

Post some pictures of your boiler and the near boiler piping. There's something amiss there if you're getting water out of your vents .

davemascera · October 4

Thanks for the comments… to start, I'm taking some restoration classes and learning to lime plaster— also having a restorer come up and teach me how to get the old windows working nice… building won't be fully insulated yet (that will happen when siding is removed and restored in years to come), but areas with bad plaster that needs to be replaced (like underneath most window sills) will get some rock wool. As an aside I had a cool idea about putting sheet mica behind some of these to reflect IR back into the room.. has this been done before?

None of the radiator vents themselves are spitting water, but there are two vents on the main. For whatever reason, they spit when it gets cold as hell out (when the pressure goes up beyond the normal 1 psi, cause I guess it can't keep up with the thermostat?). Badly enough that the pipes under have the 'vomit' Dan Holohan mentioned in his lectures under them.

The first few (maybe like 5-6?) rads get nice and hot, some of the far ones are off entirely cause the rooms are disassembled.

The sight glass goes up and down like waves in a pool when this thing is on, enough sometimes to trigger the low water sensor even if the water is in the middle when turned off! By the end of last winter I had to refill the tank once a week, about, and there was plenty of mud. I don't think there was a king valve or a valve near the hartford loop to be able to "blow out" the mud.

I'm open to thermostatic valves and variable vents but I really wanna get this system relatively balanced by default. I have many radiators out now (they're gonna need to go back in by the winter LOL), and yeah I don't wanna get them blasted and painted (cause remember my main goal is to remove and encapsulate lead here) only to find out that they're gonna be perpetually too hot. So I wouldn't mind buying or finding ones that fit/do the proper job.

I'm likely getting a new boiler too cause iron pieces are falling out of this one, and I def hear some hissing while it's on.. I'll send a pic of the near boiler piping and check out the two people you mentioned. I have a guy that does nice piping is a good guy and relatively cheap, but he certainly doesn't know about the super specifics of these systems designs (hes the guy who's afraid to mess with radiators etc.)

AdmiralYoda · October 4

It may be a very good idea to have a steam professional come by and completely inspect your system. It sounds like you have a lot of undesirable things going on. A steam system should heat evenly and equally. Yes, some radiators may provide too much heat for the room but they should all heat up about the same time.

It sounds like your boiler is having some issues. The water isn't supposed to spit out of the main vents and water shouldn't be in the mains at all unless it is a single-pipe counterflow system. The water should never bounce in the site glass more than like a half inch and definitely should never bounce enough to trigger the LWCO.

Definitely have someone here perform an inspection and possibly a replacement if warranted. You don't want to be messing around with a boiler that leaks.

ethicalpaul · October 4

You’re surging. That’s the first issue I would focus on

EzzyT · October 4

@davemascera where in NJ are you located?

Jamie Hall · October 4

Get @EzzyT or @clammy out there — especially if you are even thinking about a new boiler. Neither one of them cheap — but in the end you will get a system which works silently, correctly, and heats evenly. And cost less than patching and fiddling and band-aiding.

TRVs and such are an example of a band-aid. Perhaps worse, they cannot fix a poorly balanced, poorly piped, poorly vented system. They will just mask problems. Once you get the system working properly, then, if you want to keep one room cooler than that for some reason (your cousin from the Yukon Territory is coming to visit?) they can help with that.

pecmsg · October 4

your going to need an entire Heat load loss performed. With new insulation, windows, doors, air sealing you’ve effectively changed all the old sizing.
you could keep steam but had better get an extremely qualified person. Those 2 names are some of the best.
contact them and see how to proceed.

davemascera · October 5

Hmm, well like I said, i'm not really insulating everything just yet, also restoring the windows and doors not replacing. Insulation will probably happen when the siding gets restored in years to come.

There's a lot to consider in this thread, but seeing as how I'm doing an entire house, I don't have an unlimited budget. That's for sure.

Jamie Hall · October 5

Hang in there. Time is on your side! On the windows — if you really get them tight and working again, and add storm windows, you'll have a better assembly than any modern window would be. I applaud what you are doing!

delcrossv · October 5

If you do it right the first time, you only cry once. 😉

davemascera · October 5

https://forum.heatinghelp.com/discussion/comment/1813048#Comment_1813048

Thanks sir, I have Adam Criscuolo from White Horse Restoration coming up to train me. And going down to Limeworks for the plaster training (tools included in their intro course). I sheetrocked a bathroom that was wrecked by former owners, and it just makes me know I can never go back to sheetrock for the rest of the house.

davemascera · October 5

https://forum.heatinghelp.com/discussion/comment/1813049#Comment_1813049

Truth, but I live a weird lifestyle, I make little and spend little (relative to my peers at least). I could take out debt for heating or skimp on another project, but I gotta play the entire thing right. Obviously if the more conservative and costless troubleshooting fails I can call up the big guns and spend what I have to. Looks like I misremembered some details about my boiler wrong: 150k BTU input not 175k

and doesn't look like the year is '1983' just looks like that's the date of this standards agreement… date chart puts her at 1988 so 36 yrs old… here are pics… haven't opened the manual yet so don't know what the header calls for etc (I have the original in my attic LOL)

So some other stuff: pressuretrol cut-in set to .25 and cutout set to 2.25 (diff of 2)—- the fact that I've seen it at 5 psi means that the pressuretrol ain't really working I guess? … I thought the pigtail was made from copper in person but I guess it looks slightly brassier in this pic. No lighting rn so using the phone's flash.

Curious what you all think about this header. Looks pretty high up.

Mad Dog_2 · October 5

A "high" header is good. Mad Dog

Jamie Hall · October 5

There is no need for the differential on the pressuretrol to be that much — dial that back to 1, and then set the cutin at 0.5. Much better range. However — there is no guarantee that either the pressuretrol or the gauge is all that accurate. Might get a nice low pressure (0 to 3 psi) gauge to verify what is happening.

Piping doesn't look that bad.

dabrakeman · October 5

I can't tell easily from the photo but can you verify that this is a parallel flow system i.e. with the highest point of the mains being at their start above the boiler.

EzzyT · October 5

based on the cp number in the boiler is was manufactured before 1988

Sizing radiators in a 2200 sq ft colonial/victorian

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