Grateful for help recovering from rash changes to steam vent orifices!

RPSteam · November 4

I have screwed up my previously professionally balanced steam heat system. I'm optimistic this group can give me insight into how to reverse my ham-fisted changes. Here's everything I've got on my system. Appreciate any advice, insight, and info!

Background

I have a gas boiler and 23 steam radiators that heat my 3-story brick apartment building in Chicago.

We've struggled with even heat for years. First floor cooks, 2nd floor is generally okay with sways between too hot/too cold, and the 3rd floor (me) freezes.

I've had the entire system balanced by a steam heat pro. Here's what he did:

Installed main vents
Installed 17 Maid-O-Mist radiator vents
Pitched kitchen radiator piping on 3rd floor
Reduce firing rate of the boiler

(On the pro's recommendation I also had the decrepit asbestos removed from the pipes and insulated them with Owens Corning fiberglass tube insulation.)

These changes quieted the system significantly and heat was evened out a bit. But still when Chicago winters would get real and I cranked up the thermostat, we would have the hot on the bottom/frigid at the top syndrome.

Recent Changes

Over the years experts have recommended doing two more things: 1) a new thermostat with sensors, and 2) insulate the roof. I simply didn't have the cash for these changes.

So, during one Chicago infamous "polar vortex", frozen to the bone, I asked an HVAC guy what else I could try and he suggested swapping in the Maid-O-Mist orifice with the biggest hole in 3rd floor rooms that were typically in use (eg., the living room). I did that. It didn't really help.

New Thermostat

Fast forward to last year. Cash flow got better and in October 2024 the thermostat and sensors went in. Details:

T10 Pro Smart Thermostat with 3 wireless sensors
New boiler relay
Thermostat installed in the boiler room

Insulation

BONUS: The company that installed the thermostat got me into a state/utility energy efficiency program for apartment buildings and I was able to get my roof insulated at no cost to me! A $6000 gift!

The insulation went in this summer - and it was immediately cooler in the apartment. I allowed myself some optimism about this winter being different.

Current State (with sensor read-outs)

However, things aren't so great. Now that I have access to the sensor read-outs I can see that the 1st and 3rd floors are hot - 3rd floor is typically the hottest (a major change), and the 2nd floor is cold.

Example: heat set to 70:

the 3rd floor heats up fast to 74/75 (I love the heat but this is unpleasant),
the 1st floor heats up second to 73/74, and
the 2nd floor takes forever to get to 68/69.

Lately at night in Chicago we're down in the 40s, during the day were in the low to mid 50s. I have made sure that all apartments have windows closed and latched (sealed), no A/C's in windows, etc. All the radiator valves are open and vents are working. We are sealed in and winter ready.

I feel like I've now got all of the pieces in place for even heat in the building. I'm usually good about keeping notes on what I do with the heating system but I was so cold when I swapped in the giant orifices I don't know what I replaced.

But I do have the orifice settings for each of the radiators on the 1st, 2nd, and 3rd floors:

Current Steam Vent Sizes

1st floor radiator orifice #s, balanced by a pro:

Dining Room - Maid O Mist 6
Bedroom 1 - Gorton 5
Bedroom 2 - Dole Model 80 07
Bedroom 3 - Dole Model 80 09
Sunroom - Maid O Mist 6
Living Room - Maid O Mist 5
Kitchen - Dole No 1933

2nd floor radiator orifice #s, balanced by a pro:

Dining Room - Maid O Mist 4
Bedroom 1 - Maid O Mist 4
Bedroom 2 - Maid O Mist 4
Bedroom 3 - (bullet shaped, can't find #)
Sunroom - Maid O Mist 4
Living Room - Maid O Mist 4
Bathroom - Maid O Mist 4
Kitchen - Maid O Mist 4

3rd floor radiator orifice #s, balanced by a pro but asterisks indicate the orifices I changed...

Dining Room* - Maid O Mist C
Bedroom 1* - Maid O Mist D
Bedroom 2 - Dole Model 80 03
Bedroom 3 - Maid O Mist 5
Sunroom* - Maid O Mist C
Living Room* - Maid O Mist C
Kitchen* - Maid O Mist C

That's my tale of woe. What would be a good way to get started in walking back my changes? Thanks for reading all of this!! Appreciate any help you can offer!

Steamhead · November 4

We know a few pros in Chicagoland- was yours anyone we know?

mattmich · November 4

Looks like you have a lot to work with here… you've already made the problem move from the 3rd floor to the 2nd, so you know this'll work. That's the most important takeaway so far.

You only have so much steam. It's a matter of distribution, and that's what the vents do for you. There's also the inescapable fact that distance matters, so I'm surprised all the slow (#4) vents are on the second floor, not the first.

The #4s on the second floor are too small. The 3rd-floor ones are kind of absurdly big. I would have thought the first-floor orifices would mostly be #4s from when they were "cooking" originally. They'll probably have to go down but I'd make changes gradually.

I'd figure out which rads are most important for the second floor and put #5s in three or four of them. Heck, just exchange them with the hottest first-floor radiators; those folks probably don't want 74 F all the time, either. Communication is going to be key here, and your tenants will probably play along as long as they see improvement.

Those #5s should get steam to the second floor much more quickly. You could close a few of your top-floor vents to get away from your 75-degree problem, just as a no-cost start to the process. It's not so cold that you'll have problems, so now is a great time to play these games. I love MoM vents because the orifice is so easy to change. I'd be surprised if you couldn't just use 5s and 6s on your floor, and mostly 4s on the first.

The pros around here would probably like to know how much installed EDR you have, and the size of your boiler. I don't know enough to take that into consideration. Point being, if you have a LOT of steam, you'll want to use bigger orifices and have shorter calls-for-heat.

Have fun :)

cheers -matt

Jamie Hall · November 4

I was confused at first, but perhaps by "orifice" you are referring to the vent type and size?

In which case…

One pipe steam systems can be difficult to balance, and take some patience — as all the theory and number juggling in the world can't overcome the oddities of a specific installation. However, there is a general rule of thumb: don't try to make a space which is too cool warmer by putting in faster vents. Rather, start by slowing the other spaces.

Looking at your list of vents, then, I notice that both your first and third floor radiators have relatively fast vents — indeed, your third floor now has radiator vents which are as fast as some main vents. So.,. Where would I start? I'd start by slowing the vents on the third floor radiators. Maybe not Bedroom 2 and 3, but certainly the others. I'd drop at least one size — and I might take that D in bedroom 1 and drop it to a 6 as well.

Let it run for at least a day of heating cycles and observe. Progress? Do the same thing on the first floor for the Maid O Mists — leave the others alone for now.

Making any headway? If so, I'd start tackling individual spaces — if a few rooms on any floor are too warm, slow them down a notch. As you get closer to even heat — or more accurately heat the way you'd like it (such as bedrooms cooler or whatever) fiddle with fewer rooms at a time — and always take time between changes to actually observe what happens.

Patience…

RPSteam · November 4

@mattmich: "Looks like you have a lot to work with here… you've already made the problem move from the 3rd floor to the 2nd, so you know this'll work. That's the most important takeaway so far." I hadn't thought of the situation this way. Right!

@Jamie Hall - I like the rule of thumb: "don't try to make a space which is too cool warmer by putting in faster vents. Rather, start by slowing the other spaces."

Got it. I'll start with stepping back the vents that I "fools rush in" style stepped up.

I get what you're saying about the 2nd floor MoM #4 vent holes - they are teeny-tiny. After playing with stepping down 3rd floor vents, maybe bumping those #4 vents up to #5 will help the 2nd floor to warm up faster. But first I'm going to see if correcting the 3rd floor set up moves the needle.

One change at a time. Good idea! Thanks to you both! I'll report back - after a few days of testing and assessing.

BobC · November 5

i sujspect the roof insulation has screwed yp the balance, you now need less venting up top. The nice thing about Maid o Mist is you can just swap orifices not the entire vent. You can even buy packs of the orufices that give you a convenient way to balance your system.

Bob

dabrakeman · November 5

After making sure main venting is sufficient I would start out thinking generally 4's for first floor, 5's for second and 6's for 3rd. Modify this by radiator size (and distance from main supply riser) such that small radiators on third floor drop to a 5, large or small radiators on second floor raise or lower to 6 and 4 and larger radiators on 1st floor bump up to 5's. This would be the starting point. Tune further with patience based upon room comfort level. In your own livable space on the third floor you could use adjustable valves like a Hoffman 1a to help your balancing. If using MoM vents you can also get a pack of orifices which essentially makes them adjustable.

RPSteam · November 7

@Jamie Hall @mattmich @BobC @dabrakeman and anyone else who can spare a minute and some insight:

Here's an update and a question.

I spent the week tweaking vents in the two apartments that were running hot. Worked on the hottest one first - 3rd floor. Then moved on to work on the 1st floor.

We have gone through many heat cycles since I posted here on Monday. Sensor read-outs from this morning show below. In brief, this morning with the heat set to 70:

1st Floor: 70
2nd Floor: 68
3rd Floor: 70

Progress!

About the 2nd floor. I hesitate to change this apartment's current state because the tenant runs hot - her words, not mine. To my mind the goal with the heat is to get every single apartment to line up with the set temp (right?). By law in Chicago heat in the apartments has to be 68 during the day and 66 during the night.

I have a good idea of where to start on the 2nd floor where all of the vents are MoM #4. I have one big rad in the living room in mind to bump from #4 to #5 and that will likely do the trick.

Once all sensors hit the same target, I'm thinking people can do what they need to do to get their space comfortable - turn on a ceiling fan, crack a window, drink a cold beer - whatever. Just like in summer - some have A/Cs going all day and night, others don't have A/Cs at all.

I don't like the idea of paying for heat that's just going out of a window, but that's a different concern. Or is there more to that? When it's 10 degrees out, is heat going out of the 2nd floor window going to screw up the heat for the other units?

The goal is to BALANCE this system and that means get the 2nd floor temp equal to the 1st and 3rd - right? Any other things to consider?

Thanks!

Jamie Hall · November 7

You are certainly making progress! Congratulations!

In a sense yes, the objective of balancing is to get all the spaces to heat evenly and to the same temperature — all else being equal. But… all else is not equal. So in my mind anyway the objective is to get all the spaces so that most of the time their temperature is what the usage or and occupant in the space are happiest with. Not quite the same thing.

RPSteam · November 7

One new thought on one apartment's open window throwing everything off -

Since I can select which sensors are used in the thermostat's averaging, once I've got all apartments balanced couldn't I just turn off the sensor for the 2nd floor and use only 1st and 3rd floor sensors to base temps on?

dabrakeman · November 7

I, to my great pleasure, have no direct experience with big city heating mandates but need to ask the question whether the intent of the 68/66 minimum temps is one of actual temperature or system capability? If the second floor tenants are happy being 2 degrees cooler than the first and third floor tenants are you not allowed to leave it there until those tenants leave and others arrive, or, does law force you to have them open the windows at night to get what they want…? Probably the latter because the former would be way to logical.

This doesn't mean that you wouldn't want to know ahead of time how to indeed get the second floor balanced.

mattmich · November 8

Congratulations on getting to a good place from a bad one!

I'd love to know what you changed about those gaping vents on the third floor.

@Jamie Hall said it well:

» most of the time their temperature is what the usage or and occupant in the space are happiest with.

That I think should be the goal, never mind the number in an ordinance.

With that in mind, I'd leave the 2nd floor with #4s and give the tenant a few #5s on a piece of string, and tell them to adjust as needed. If their bedroom is too warm, tell them to plug the #4 with a toothpick and leave the door open. A lot of people prefer sleeping in a cool room, me included.

@dabrakeman mentions the law, and it's a concern for sure, but I think this is a case of "where there's no complainant, there's no judge."

The law is useful in the sense that it gives tenants rights when the heating system doesn't work, but if your tenants are comfortable they're not going to worry about it.

With the 1st and 3rd floor in lockstep, it's probably best to leave those alone.

There is one potential issue: Pressure. Depending on how oversized your boiler is, if it cycles on pressure, which is inefficient, you'll want to open up some vents so you can make use of the steam quickly and keep the calls-for-heat shorter.

If there's no cycling, count your blessings and touch nothing.

cheers -matt

Grateful for help recovering from rash changes to steam vent orifices!

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