Bottom floor is 5 degrees colder than top floor

mholzap

I feel like I've tried every trick, including the recommendations in "We Got Steam Heat!", and still can't get my house to heat evenly!

Here's the full situation -- sparing no details!

• It's a two-story house in the Boston area, built in ~1930
  
• Upstairs has four radiators, downstairs has five radiators (foyer, kitchen, living room, dining room, and bath... the family room is an attachment with baseboard heat) -- see picture of floor plan for more detail. All radiators are single pipe steam radiators
  
• The upstairs radiators in the bedrooms and office are ~36" wide. The downstairs radiators in the living room and dining room are ~52" - 48", respectively
  
• The thermostat is in the dining room. I installed a Nest 3rd Generation
  
• Boiler is maybe 5-7 years old
  
• Upstairs is consistently 3-7+ degrees warmer than downstairs. If I set the thermostat at 67-68 then the difference is on the smaller end (~65 degrees downstairs, ~71 degrees upstairs). If the thermostat is set to 69-71 then the upstairs is a sauna -- 80 degrees+ -- and the boiler fires very frequently
  
• The Nest seems to consistently measure the room temperature as 2-3 degrees warmer than the actual temperature
  
• I've replaced all the vents with Hoffman 1A, 1/8" Adjustable Angle Steam Radiator Air Valve, and set upstairs to the slowest setting, downstairs to the fastest
  
• I adjusted the pressure on the boiler to have cut in of ~1psi & differential of 1psi
  
• Some of the downstairs radiators weren't pitched, so I put some shims in to fix that
  
• I've replaced a few of the valves on the downstairs radiators (kitchen, bathroom, and entry way), which were the only ones I was able to get off
  
• All the valves are completely open
  
• The downstairs radiators don't get hot at the bottom and stop heating much earlier than the upstairs ones
  
• There is quite a bit of clanging under/near the downstairs radiators
  
• The downstairs bathroom's radiator doesn't get hot at all. When it's really cold outside and the temperature on the t-stat is a little higher, it will hiss and make a lot of banging sounds, but not get hot
  
• The boiler's water supply goes near the bottom on the gauge when the house is heating (see picture). I've read conflicting things online if that's a problem. The water itself is quite brown during heating season. It clears up in the summer.
  

Now for some pictures...









Appreciate any ideas you have!! Early on, I tried partially closing some of the upstairs valves and that helped a bit, but then I found out that's not an appropriate solution

nicholas bonham-carter

The adjustable Hoffman 1A’s are not a precision fit in the rotating cap, so you may still be over venting the upstairs rads due to the sloppy fit of the rotating cap.
What sort of main vents are on the system, (they do the heavy lifting of air removal). A low pressure 0-3 psi gauge would show you how adequate your venting is.
For banging radiators, the problem may be in a wrongly pitched lateral pipe under the floor. Raising all four feet and shining with washers or quarters can sometime rectify that.
Others will point out the unsuitability of the Nest for non forced air heating. Honeywell VisionPro (set up for steam in the configuration), seems to be the best, with a remote sensor, and WiFi if you want. Set the temperature, and leave it there for greatest comfort and economy.—NBC

Jamie Hall

The very first thing to do -- though not necessarily the easiest (the manual is, to put it charitably, opaque), -- is to the disable all the learning, occupancy, and setback features on the Nest, and make sure it is set for "true radiant". It's still a miserable thermostat for controlling a steam heating system, but at least that will kill most of its vices. Then set it and forget it. You may be able to get away with as much as a 3 degree setback -- but maybe not.

Then... slow down the upstairs radiator vents. As @nicholas bonham-carter said, the Hoffmans are a little tricky to adjust, but adjust they will.

The banging -- and probably the poor heat in that bathroom -- is probably mostly from poor pitch of the runout pipes to those radiators. Check all of them -- they must have a drop of at least 1 inch for every 10 feet of horizontal run. Also -- what size pipe was used for the runout to that bathroom? it may simply be too small, depending on how long it is. While you are at it, but after you have checked and fixed any pitch problems, make sure all the mains and runouts are insulated.

As @nicholas bonham-carter said, do you have main vents? Are they working? Are they big enough?

speedbird

I'm certainly not a professional, but I feel like I have figured out the basics of good steam heating and balancing. Take it or leave it, but I'd change all your vents to Gorton vents: https://www.gorton-valves.com/products. They have a great diagram for getting the sizing right (in my opinion adjustable vents are garbage), and I'd get rid of that Nest thermostat. Steam works best with insulated pipes and a thermostat set to a constant temperature (with minimal setback at night or if house is empty for extended periods of time, but 1-2 degrees max). You also want to make sure that the thermostat is set to 1 cycle per hour. The Nest works best where it can "fine tune" your usage, for things like AC systems / force air heating systems, totally wrong for steam.

EBEBRATT-Ed

You may need to skim the boiler. How is the water level when it is steaming? Does it bounce a lot? over an inch? With your water level that low you may be going off on the low water cutoff.

How about a few pictures of the boiler and the piping around it?

+ check all your piping and radiators for pitch as others have mentioned above

mholzap

Thanks for the ideas! Here are a few pictures of the boiler and the piping around it. The last picture is the pipe leading to the living room, which is cold.

I had not noticed the vent before. It looks in rough shape. Should this be replaced?

The water level bounces a lot when it steams. That picture I took of the water level being towards the bottom was during steaming. Before steaming, the glass was 90% full

KC_Jones

First the pipe leading to the living room is copper, that will tend to condense steam much faster than the black pipe and could contribute to it not heating. Also, what size is that copper? It looks small, and if too under sized it may cause the steam to not want to go there due to slightly higher resistance with the smaller pipe. Steam can be very sensitive to this.

I'd also suggest evaluating the main venting. I can't tell what you have, but guessing it's not adequate. need size and length of mains and we can recommend an amount of main venting.

Jamie Hall

If that copper pipe leading to the living room isn't insulated, steam may never make it at all...

mattmia2

Does the level move up and down while it is steaming, or does it just get lower and stay relatively stable at that lower level?

SteamingatMohawk

1. I don't see any insulation. How warm is your basement? All of the piping leading to the radiators needs insulation, otherwise you are not putting the steam where you want it.
2. What happens if you keep your second floor doors at the stairway shut? Heat rises and your stairway isn't all that large.
3. I'm far from a student of boilers, but 90% full gage glass when cold and low level when steaming doesn't seem right. Jamie and others are well versed on that stuff. That seems to be a lot of water/steam being stored somewhere.
4. What brand and size of radiator vents do you have installed at each location?
5. If you don't have main venting or they are not functioning...fix it. For the first time in 31 years, I had a vent stick shut. I haven't yet taken it apart to find out what happened.
6. Exactly where in the room is the thermostat? If it's close to the kitchen, there could be heat from cooking affecting how long the thermostat wants heat. I know that seems backwards because the second floor is warmer, but though it might give a useful clue. Conventional wisdom is for it to be in the coldest room in the house. Once that is satisfied, you can tweak the others. I realize in a two story single family house this may not be desirable, so it's food for thought. Not all of the guys on HH advocate this, but it works for me.
7. This is a wild one, but you might want to remove each vent individually to make sure the radiator is getting steam. Do this verrrrryy carefully and at low pressure like at the beginning of a cycle. You probably will have to shut the isolation valve to the radiator to reinstall the radiator vent. Verrryyy carefully. If you aren't mechanically inclined, skip this...don't get hurt!

Chris_L

Hmm. Can anyone figure out what that large vertical pipe is on the left in the first photo, and in the middle of the second? It looks like it is connected to one of the mains on one side and then to ??? on the other, and is Tee'd in the middle dropping down to ???. And yet there is a dry return with a vent beneath the main in the first photo.

It would be helpful if the OP could trace out just where all these pipes are going.

Jamie Hall

The piping is a bit unusual...

It's pretty normal for the water level to drop -- and hold -- a couple of inches while steaming. Shouldn't drop a while lot more than that.

mattmia2

Chris_L said:

Hmm. Can anyone figure out what that large vertical pipe is on the left in the first photo, and in the middle of the second? It looks like it is connected to one of the mains on one side and then to ??? on the other, and is Tee'd in the middle dropping down to ???. And yet there is a dry return with a vent beneath the main in the first photo.

It would be helpful if the OP could trace out just where all these pipes are going.

Looks like the gas to the boiler.

EBEBRATT-Ed

The op said the water level is bouncing a lot. That is probably means wet steam. Piping isn't great and header may be undersized. That and skimming

mholzap

Thanks for the feedback! It is seeming like the insulation is the big problem. I noticed the upstairs radiators are heating up much earlier in the heating cycle than the downstairs radiators. And when I follow the pipes in the basement leading to the downstairs radiators, it seems like it takes a bit of time for the full pipe to get warm. The basement is pretty cold, so I suspect the steam is running out of steam until the system warms up enough to push through. I'll get some insulation this weekend and install it. I'll also try the Honeywell thermostat

The thermostat is located on the wall butted up against the living room wall, so I don't think the location is an issue.

@KC_Jones I provided a diagram, that's hopefully legible, of the piping near the boiler. If you have a recommendation on vents to use, I'm all ears!

@Chris_L See diagram for the layout.

@SteamingatMohawk I may have fixed the bouncing water issue. I emptied the boiler and refilled it with fresh water. Now the water in the sight glass is only bouncing an inch or two (instead of 1 foot+), which sounds normal.

Thanks again everyone!

KC_Jones

If I was doing new main vents I’d do a Gorton #1 on the short main and 2 Gorton #1’s on the longer main.

Do you know what the main vents are now?

mattmia2

The unequal heating of the mains is likely lack of main venting on the main that takes longer to heat, although it could be something like trapped condensate if there is a pitch issue in that main.(could be related to the surging throwing water in to that particular main too)

If the water is bouncing in the boiler it probably needs to be skimmed. that bouncing will throw water up in to the mains, especially since whoever installed it only used one of the outlets from the boiler in to the header.

mholzap

KC_Jones said:

If I was doing new main vents I’d do a Gorton #1 on the short main and 2 Gorton #1’s on the longer main.

Do you know what the main vents are now?

The main vents now are Ventrite 35s. The longer main only has one vent right now. Is there an easy way to add two vents as you recommend?

mattmia2

You can use a black iron tee and some ells and nipples to connect 2 or more vents to the same tapping.

BobC

I'm glad draining the boiler and refilling it calmed the water bounce. That said it will not stay calmed long.

In a short while the bounce will be back, the only way to fix this is with a few nice long skimming sessions. The surface water of the boiler has to be slowly allowed to float o4ff and out of the boiler skim port. Do you have a skim port installed on that boiler? The manual should show where it should be.

Contractors don't like to skim because it takes hours, it's a job you pretty much have to do yourself. You may need to have contractor install a skim port if you don't have one because a old boiler plug can be a bear to get out.

While skimming you can be installing those Gorton or Maid O Mist #1 main vents.

Bob

KC_Jones

mholzap said:

KC_Jones said:

If I was doing new main vents I’d do a Gorton #1 on the short main and 2 Gorton #1’s on the longer main.

Do you know what the main vents are now?

The main vents now are Ventrite 35s. The longer main only has one vent right now. Is there an easy way to add two vents as you recommend?

@mattmia2 has it right for how to add multiple vents

The recommendation I gave will vent your short main about 3x faster and the long main about 6x faster. I suspect this is contributing to the problem, but most likely not the entire problem. Balance starts in the basement with main venting.

ChicagoCooperator

Not to beat a dead horse, but is your thermostat by any chance on the wall which seems to have a fireplace on the other side of it? I'm wondering if that's where your boiler flue and hot water heater flue goes and I wonder if that is heating up the wall. It wasn't totally clear to me if you meant that wall or the wall that backs up directly to the living room on the other side.

dabrakeman

1) Those Ventrite main vents are inadequate for most any system. A Gorton #2 has 10X the venting capacity and a Gorton #1 ~3.3X the venting capacity. Put a Gorton #2 on your long main and you can put an antler on the other and use your two existing Ventrites (if they work..) and a new Gorton #1.
2) Insulate those pipes (start with that copper one) and while at it take notice of the pitch of the pipes. If there seems like a spot that water could get trapped then it likely is which will lead to hammer or even lack of steam.
3) Verifiy the pitch of each radiator
4) I wouldn't worry about changing out thermostat based upon your observations until evaluating the effect of the above items. As Jamie said make sure it is on radiant heating and turn off learning features and any occupancy detection. Make sure you know what either your cycles per hour or swing temperature is (not familiar with the Nest but you would want to start out at either 1 or 2 cycles per hour or a swing of maybe 1 degree). Lower swing will give shorter cycles and higher swing longer cycles. Start simple until you fix your balance issue meaning just set a constant temperature with no setback or just a degree or two at most. Once you fix the other issues you can then start seeing what setback if any your system can handle.
5) I don't think adjustment of your Hoffman 1a's is the issue but they are a bit finicky. Totally unscrew the top disc so you can lift the cap right off. Then you can see how it adjusts. The nautilus shaped disc as it is turned just covers more and more of the vent hole. That's it. Now you can see how centering of the cap can severely impact its adjustment... Good enough vents though otherwise. If you need better low venting control on the upstairs radiators the Ventrite 1a is best bet. Can tweak it down to zero.

SteamingatMohawk

Notwithstanding negative comments about adjustable radiator vents, if you want to learn more about the venting capacities of many brands and sizes, look at this report;

https://heatinghelp.com/systems-help-center/balancing-steam-systems-using-a-vent-capacity-chart/