NEAR BOILER PIPING CHANGED...SYSTEM IS NOT THE SAME

Do you have main vents

What pressure is the boiler operating at, it should be below 2 PSI. You need properly sized main vents and you should probably throw out all the heat timer varivalves - they are must too aggressive for single pipe steam.

Bob

You also mentioned 5 large radiators in the living room. Heattimer vents are notoriously fast vents. GW Gill ran into a case where one radiator would not heat no matter what he did. He even pulled the vent from the radiator and nothing. Issue was the heater timer vent on other radiator was so aggressive that the radiator was in a state of constant vacuum. Steam goes from high to low pressure always. Vacuum is a lower pressure than atmosphere.

Turn down the living room vents.

I would get the installers to redo the piping in conformity will the manufacturers requirements, in case you have a warranty boiler replacement needed in a couple of years.
The mains still need lots of main venting, and it could be done at the tops of each of the risers with a couple of big mouth vents each. In these cases you are allowing the air in the pipes to escape at the lowest possible resistance, (back pressure under 2 ounces). The valve bonnets and stems could be removed, and tapped for a menorah of big mouth vents.
When the mains are full, then the steam will enter the radiators all at the same time.
Did you tell us how the system is controlled?—NBC

Actually if it is exactly like C it is still wrong as one of the system take offs is between the boiler risers which isn't correct.

Pictures are really needed here, sketches can't usually capture the subtleties.

This is almost certainly a venting/balancing issue. The questions and advice of others earlier are almost certainly correct. Let's summarize:
1. old boiler, vents and piping worked ok, system was balanced enough that you didn't report complaints.
2. New boiler installed, slight problem with header, riser takeoffs which was fixed.
3. Before header/riser repaired, boiler run at 6 psi, destroyed all your vents. You replaced with Heatimer varivents.
4. Tenants still complain of unbalanced heat in apartments: too hot in living rooms with very large radiators, too cool in the other areas served by the two other risers.
5. Pressuretrol set at 2 psi, no report on whether this is cut-in or cut-out.

To summarize the suggestions above I'd suggest going back to "normal" one pipe steam arrangements and do the following:
1. Set pressure-trol to 1.5 cut-out, 0.5 psi cut-in.
2. Add main steam vents to the top of all three risers, if you need help in sizing post exact size of mains, risers and distances, but you indicated a 5 story building (say 40 feet from first floor to 5th floor) and horizontal mains in basement are 15 feet for the living room riser and 25 and 40 feet for the mains leading to the other two risers. Total distances are 55 feet to top of living rooms riser, 65 feet to top of center riser, and 80 feet to top of the bedroom riser. Because of this configuration you must consider the vertical risers as "mains" and try to vent all three so the steam arrives at the top of all three risers at pretty close to the same time. You can use your hand or infrared thermometer to tell when the steam gets to the top of each riser. If it were mine, I'd add the equivalent of one Barnes & Jones Big Mouth vent on each riser, with perhaps more venting on the furthest riser from the boiler (bedrooms you said). Add the vents to the piping BEFORE the radiator valve on the top floor.
3. Remove all the heatimer varivents. These are, as said by others earlier, probably too aggressive and if on the large living room rads are probably preventing steam from getting to the rads on the other risers (because the others are further away from the boiler and the path of least resistance for the steam is to the living room rads with very fast vents even at the lowest setting of the varivent). I'd suggest trying either Hoffman #1a or Vent-rite #1 adjustable vents (I like the vent-rite vents personnaly) these are easily adjustable and will help you enormously to balance the system. If you knew what make/size vents were originally installed at each rad you could probably use those, but that may be hard to determine now. Conversely to what you would think, adding fast vents to the radiators is often not helpful. As is said many times on this site, vent the mains quickly and then vent the radiators slowly and proportionately to their size and the comfort in each room you want. Maybe start all the adjustable radiator vents on a mid range setting (say 3 or 4), then slowly over a few days turn up (faster) the ones where the rooms are too cool and turn down (slower) the ones in the rooms that are too warm.

From all you described I'm pretty certain this will work for you. You haven't mentioned water hammer (banging) and the near boiler piping seems about right (doesn't have to be perfect unless you have some problem symptom like water hammer).

If you have trouble with the individual steps, post back and I'm sure someone will help with each step.

Maybe someone who knows the Ecobee controls could chime in here?

If you have a timer in the soup, it becomes more essential than ever that the venting be not just good enough, but excellent. All the above comments on vents are spot on, as well as insulating the dickens out of the mains -- and perhaps the risers, if you can. Uninsulated pipes slow the steam a lot, which venting won't help. Poor venting also slows the steam, more obviously, and you really need to get it so that the farthest radiators get steam within a very few minutes -- certainly less than a quarter or less of the timer lock out -- to get the system balanced.

If the vents on those risers are the only vents on the system (shy of the radiators) ,Gorton D' aren't nearly enough venting to move the air out of all of the mains and risers. You probably need multiple Barnes and Jones Big Mouths to get the air out quickly. Why are you putting them on the forth floor instead of the fifth floor? The vents need to be at the top. If you can tell us how long and what diameter each main is as well as the risers, we can tell you how much venting you should have on each. Also, remember it is a waste of time to try to balance the system until the main venting is correct.
If there are oils on the surface of the boiler water, that oil makes it very difficult for the steam bubbles to break through and burst, releasing the steam. That means more turbulent water and less steam for your fuel dollars. It is critical that the boiler be skimmed well.

1. Insulate the visible steam mains in the basement as Jamie Hall suggested.
2. Install as large as feasible vents at or near the top of all 3 risers. B&J Big Mouths or Gorton #2's at least. I realize the practicality and aesthetics may play a role here. Easiest place may be at the top of the 4th floor near the ceiling (its only a foot or so from the end of the riser on the floor above and won't make much practical difference). Better, but not essential to locate them at the top of the riser on the 5th floor, but if you can't, you can't (might require changing pipe work, adding a T where the rad valve is, getting new straight rad valves and accompanying spud, and moving the rad slightly sideways--a good amount of work. If you put them on the riser at the 4th floor ceiling you may have trouble drilling and tapping a 1-1/2" riser pipe for a 1/2" or 3/4" vent, if so, you can use a Romac service saddle, 101U or 101S from Romac Industries, BUT GET THE SPECIAL ORDER EPDM GASKET FOR STEAM SERVICE. These service saddles only require drilling an appropriate size hole in the riser and then adding a 90 deg elbow and nipple to the service saddle to mount the vent. The service saddle and elbow/nipple can be painted to match the riser. I happen to like the looks of the brass B&J Big Mouth vent, have one in one of my finished bathrooms, no complaints after a week or so. Like lots of things after it's there a while it disappears.
3. Get rid of the heatimer vari-vents, put slower vents on the radiators preferably adjustable vents. Adjust vent rte as needed to get balanced heat.
4. Turn the pressuretrol down a little if possible 1.5 cut out, 0.5 cut-in--just a matter of turning the top screw and dial inside to the correct settings.

The above 4 steps will be needed in any case, even if your boiler piping is not exactly right and even if you need skimming. You will be pleasantly surprised how much these 4 steps will go to balance the heating in your building.

Skimming never hurts, so do it if you can, but may not be essential. Does the boiler water line move up and down by large amounts when the boiler makes steam? (skimming probably needed if it moves up and down more than 1/2 to 1" or so, 1/2" to 1" movement is about normal.

You haven't indicated noise concerns like water / steam hammer so even if the near boiler piping is not perfect, it may not matter. Plenty of near boiler piping installs work fine if not perfect, including my own. So do the 4 essential items above then if needed move on to other more difficult items, like changes to the near boiler piping.

post back as you move ahead. We're all interested in the results.

One more thing, are these riser pipes through the apartments uninsulated and exposed? If so they too would help the system by insulating them, particularly the riser through the living rooms. You can get 1" thick fiberglass insulation for 1-1/2" pipes in 3 or 4 foot lengths and if you want a better looking finish you can get easily applied PVC insulation jacket. Here are two links to Grainger products, but I'm sure you can buy them plenty of other places as well.
https://www.grainger.com/product/JOHNS-MANVILLE-1-Thick-45NE17

https://www.grainger.com/product/JOHNS-MANVILLE-5-Max-O-D-White-PVC-Insulated-6ZKJ5?cm_sp=Product_Details-_-Products_Based_on_Your_Search-_-IDPPLARECS&cm_vc=IDPPLARECS

This is a pretty easy do it yourself project, and can be attacked in stages (not all at once).

I've had good luck with orders from Buyinsulationproducts.com
They deliver right to your door. http://www.buyinsulationproductstore.com/pvc-90-deg-elbow-cover/

Here's a picture of a Big Mouth vent on a Romac service saddle on a 1-1/2" main in a finished bathroom. If you insulate the main the insulation will mostly cover the service saddle. You can paint the elbow and nipple white to match the insulation cover.

Doug83 said:

Thanks again everyone for recent recommendations. You can't buy this type of help and advice, obviously! @Gary Smith , I looked at pictures of the installed pressuretrol. They installed an L404F (honeywell) which has a min of 2psi main and 2psi diff. I asked the contractor to swap with one with smaller increments so I can get 1.5 psi.

I know every system has it's quirks, but I am having a difficult time understanding why on a brand new install you are hitting pressure like that. The pressuretrol is supposed to be a safety device not an operating control. In my opinion under normal operation you shouldn't ever shut down on pressure. If you are coming back from setback and running a vaporstat at low pressure I could see it, maybe.

The pressure should be set by proper boiler sizing and venting.

Are you absolutely sure they sized it properly? They went into every room and measured every radiator? They then compared that number directly to the manufacturers rating? That's the only way to get the sizing correct. Honestly unless you are running for an hour or more I am not understanding how you are hitting these pressures, unless the boiler is over sized or the venting is terrible.

Related to that this statement is actually concerning:
"It was sized at the same EDR of last boiler in analysis, which was probably sized to heat with the windows open..."

@KC_Jones , I agree, weird to see such high pressures. That's why I think his problem is mainly in the lack of venting and relying on the radiator vents to vent all the risers and main piping. All steam boilers are oversized by a lot on all but the coldest (design) days and yet they will not build significant pressure--the rad's do not get hot all the way across to satisfy the thermostat--usually. My own house boiler (35 years old, 1-pipe) had no main vents and several rads removed with cast iron baseboard installed in place. Heated very unevenly, second floor 8 degrees hotter than first (where thermostat is). Once I installed main vents, insulated the mains and put in variable radiator vents, and removed all the heatimer vari-vents, all rooms are within 1 degree of each other. Same boiler, still oversized by a lot, never builds more than 4 oz (1/4 psi) pressure based on a good 0-3 psi gage. I do have a vaporstat in addition to the two original pressurtrols and it never shuts the boiler off--always off on thermostat. In my case I'm sure the radiation is oversized for the space, the boiler is oversized for the radiation, but once I insulated mains and with good venting, the boiler always shuts off on satisfying the tstat, never vaporstat or pressuretrols--they operate as you say as safety devices, the tstat is the control device.

@Doug83 , Don't let these discussions overwhelm you. There are some basics that you must take care of, regardless of the sizing of the boiler.
- a Pressuretrol set at a Cut-out of 2 PSI is fine. Don't spend money on one that can be set at 1.5PSI.
- Insulate all pipes as much as possible. Un-insulated pipes will cause the steam to condense faster and cause the boiler to run longer to get steam to the radiators. The longer the boiler runs, during a heating cycle, the greater the potential for pressure issues, especially if the boiler is over-sized.
- Get as much venting on the mains/risers as is necessary to allow the air to be expelled as quickly as possible. That will reduce the amount of time the system has to run pushing air out so that steam can get where it needs to be AND reduce the pressure that builds up during the heating cycle. This venting has to be done and correct before you can balance the heat to each radiator.
- Once you have these things done, if the boiler still shuts down, excessively, on pressure, then we can suggest a few ways to improve that, maybe down firing, maybe a two stage gas valve. Whatever the remaining issue may be, it can't be properly diagnosed until the basics are done.