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Converted two family

I have a 90+ year old converted 2 family house that is now 4 @ 1 bedroom apartments, 2 up, 2 down. The single pipe steam system has two headers, one to the front and one to the rear. The entire system is controlled by 1 thermostat in the downstairs front living room. I read the article about zoning, but it seems to be for a much larger building. Is there any successful way to split the system to 2 or 4 zones?


  • Jamie HallJamie Hall Member Posts: 12,852
    You've just hit the one really notable problem with steam: while conceptually it is simple enough to split such a steam system into zones -- particularly when the piping is conveniently arranged, as yours probably is -- you run into the problem of the boiler being seriously oversized when only a fraction of the zones is calling for heat.

    If the installation is big enough that one can apply some probability to it, one can use arrangements such as the HeatTimer or other timer based controls, with the timing set by an outdoor thermometer, coupled with a smaller boiler, basing the sizing on how many units will probably be calling at any one time, and this works pretty well. With only four zones... perhaps not.
    Br. Jamie, osb

    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England.

    Hoffman Equipped System (all original except boiler), Weil-Mclain 580, 2.75 gph Carlin, Vapourstat 0.5 -- 6.0 ounces per square inch
  • the_donutthe_donut Member Posts: 374
    Instead of zoning you could use trvs in rooms other than thermostat and locate thermostat in coldest apartment.
  • SteamingatMohawkSteamingatMohawk Member Posts: 251
    @Jamie, @the_donut

    To both replies, thanks for the suggestions. I will look into them. I currently use adjustable Vari-valves on every radiator to control venting. I have seen trvs, but am skeptical about how well a thermostatic valve mounted very close to the radiator actually performs.

    I am not familiar with Heat Timer controls, but assume it maintains pressure/temperature within the boiler, ready to supply steam to a zone on demand. I haven't looked into the real workings of controlling the boiler based on outdoor temperature. Possibly, keeping the boiler hot and only supplying heat on demand would work. Do you have any feel for whether it results in cost increase or decrease over time?

    Great suggestions, thanks again.

  • BobCBobC Member Posts: 5,107
    The varivalves are harder to control, once get good main venting installed you will find you have turn all of the way down. Truth be told you would probably be betteroff with Ventrite #1 adjustable vents.

    Heat Timer controls are good but expensive for a small property, see how far you can get with good main venting and slow radiator vents before jumping down that hole.

    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
  • nicholas bonham-carternicholas bonham-carter Member Posts: 8,133
    Heatimer, and Tekmar steam controls use a combination of indoor, and outdoor temperature to control the boiler. They are better suited to very large buildings, whereas for yours, a Honeywell VisionPro thermostat, with a remote wired sensor in the most exposed room in the building should keep everyone comfortable. The control part can be in a secure area accessible only to you.
    No control system can overcome problems with an unbalanced, and badly vented system, so getting those things correct should be first on the list, even before the control change.
    Any control system which kept the boiler running constantly to maintain even low pressure would short-cycle itself to death, and spin the gas meter like a roulette wheel.—NBC
  • SteamingatMohawkSteamingatMohawk Member Posts: 251

    I had Gorton #1s on each of the two condensate return legs just before returning into the boiler fill connection and was advised by the company to replace them with #2s, which I did. I didn't realize the physical size difference, but was able to install both #2s at the same location as the #1s. That made a big difference.

    I also have had the radiator vents at the top of the radiator, which I learned is not correct. I will move them to the middle after the heating season. I am going to wait, because the vents have been at the top since before I bought the house in 1989 and I can't get the plugs out easily. I don't want to take the system off line during the heating season if I have to drill out the plugs and use easy outs (which I avoid using as much as possible). I have had bad luck with small diameter drill bits easy outs breaking and making a simple job much more difficult. That change should help.

    I will look into the VisionPro thermostat.


  • SteamingatMohawkSteamingatMohawk Member Posts: 251
    If I do end up with zones, whether with a steam system or something else, I have some locations that could benefit from a thermostat that doesn't have wires to a controller for the system/zone valve(s).
    The controllers I have seen are all hard wired to the thermostat.

    Has anyone come across a thermostat that can wirelessly communicate with a controller for a zone valve?
  • the_donutthe_donut Member Posts: 374
    edited March 2018
    You might be able to get the plugs out by scraping paint and using penetrating oil a few times. I was able to get a plug out from a Detroit flue American radiator circa 1897 this way. Plug was original to radiator and had several coats of paint on it.
  • SteamingatMohawkSteamingatMohawk Member Posts: 251

    I plan to do that as well, but since the house is 90+ years old and I have not touched the plugs in the 29 years I have owned the house, I am being careful. By the way, I now use PB Blaster instead of WD-40 to loosen rusted bolts, etc.
  • nicholas bonham-carternicholas bonham-carter Member Posts: 8,133
    That system would be best in a larger building with a very badly maintained system where the occupants alternately roast or freeze.
    If your system is balanced through proper venting, the room temperatures should all be pretty close, especially if you use no temperature setbacks.—NBC
  • SteamingatMohawkSteamingatMohawk Member Posts: 251
    Nice concept, but I don't see where it interacts with the boiler controls. I emailed that question to the company. I'll post the reply. Thanks for the suggestion.
  • the_donutthe_donut Member Posts: 374
    edited March 2018
    The cozy is pretty neat. Basically if overheating, it insulates the radiator so heat is trapped and steam stops condensing, ergo less btu in.
  • SteamingatMohawkSteamingatMohawk Member Posts: 251
    The company explained how it works, but has no solution for a house with 4 apartments and only 1 thermostat. When I had the current boiler installed, the plumber said I could not use multiple thermostats, so I eliminated the other two. The fourth apartment never had a thermostat for as long as I had owned the house and who knows how long before then.
  • JackJack Member Posts: 1,044
    How large are these 1 bdr apts?
  • SteamingatMohawkSteamingatMohawk Member Posts: 251
    No more than 10 x 10. The house is 90+ years old.
  • SteamingatMohawkSteamingatMohawk Member Posts: 251
    I'm striking out on a successful way to zone the system. Let's hear opinions on which thermostatic radiator valve I should use. I'm referring to connecting at the 1/8" vent hole on the radiator. What I found interesting in looking at them is the literature shows them at the top of the radiator, while Dan's book says put them in the middle. Comments?
  • nicholas bonham-carternicholas bonham-carter Member Posts: 8,133
    Leave the TRV's as a last resort, AFTER fully venting and balancing the system, with maybe a thermostat relocation, if needed.
    You can buy a lot of venting for the cost of TRV's, and you definitely need adequate venting.--NBC
  • SteamingatMohawkSteamingatMohawk Member Posts: 251
    Agreed; the challenge is where to locate the lone thermostat in a 4 unit building.
  • nicholas bonham-carternicholas bonham-carter Member Posts: 8,133
    Is there one unit which is more exposed, and therefore colder than the others-maybe the top floor on the north west?—NBC
  • SteamingatMohawkSteamingatMohawk Member Posts: 251
    Here's the layout. Former two family facing north, up and down, front and back apartments.
    Down front has basement beneath, apartment above, front faces north. Thermostat on interior wall

    Up front has apartment below, attic with 90+ year old insulation above, but new metal roof with OSB underlayment beneath the metal, faces north. Probably the coldest apartment.

    Down back, closest to boiler, has chimney inside the apartments and pipes to second floor apartment contributing to the heat, faces south, but has unheated indoor stairway between the living room and the exterior. Probably the warmest because of proximity to boiler and additional heat pipes to second floor

    Up back has apartment below, chimney, attic above, and faces south, also has the back stairway. Probably second warmest apartment.

    My guess is the up front apartment is the coldest because of attic and north face. Challenge is to get the wiring for a thermostat to it. Annoying, but possible task. I have been thinking about how to do it and may have a simple solution because I had to open a chase that had a freak drip from one of those drain taps on a valve inside the chase. It really threw me for a loop, but the fix was easy. I can send pics to anyone interested. This was one for the record books.

    Thanks for asking.
  • SteamingatMohawkSteamingatMohawk Member Posts: 251
    Occasionally, one of the mixing tubes will have the flame inside the tube. I don't know what causes this, but I have used soft copper wire to make sure the orifices are clean. Does anyone have any idea if low humidity could allow static to attract and accumulate dost on the orifice, making the mixing tube flame be inside vs where it belongs? I also found that the mixing tubes "walk", I put them against the orifice flange and days later they have moved a fraction of an inch toward the back of the boiler. I made aluminum clips to hold them in place.
  • Dave in QCADave in QCA Member Posts: 1,759
    Yes, it sounds like you have identified the coldest apartment. Put the thermostat there. Then get your venting straightened out. For even distribution of steam, the rule is, vent the mains FAST and your radiators SLOW. When this is not done, you get uneven steam distribution and in a steam cycle where the radiators only partially heat, you will have some that are fully heated and others that are barely warm at all. This of course causes the apartments to be wildly different temperatures.
    Dave in Quad Cities, America
    Weil-McLain 680 with Riello 2-stage burner, December 2012. Firing rate=375MBH Low, 690MBH Hi.
    System = Early Dunham 2-pipe Vacuo-Vapor (inlet and outlet both at bottom of radiators) Traps are Dunham #2 rebuilt w. Barnes-Jones Cage Units, Dunham-Bush 1E, Mepco 1E, and Armstrong TS-2. All valves haveTunstall orifices sized at 8 oz.
    Current connected load EDR= 1,259 sq ft, Original system EDR = 2,100 sq ft Vaporstat, 13 oz cutout, 4 oz cutin - Temp. control Tekmar 279.
  • SteamingatMohawkSteamingatMohawk Member Posts: 251
    It's been a while since I logged in.

    I finally took the time to eliminate my rollout switch tripping issue. It was all my fault because over the years, insulation had fallen off the sides of the base for the boiler on both the rear and front. Additionally, the front part of the base got so hot it warped, breaking two spot welds that hold the bracket for the pilot viewing window/ "base door assembly" allowing heat to escape even more easily. I was not aware I could obtain replacement insulation from the boiler manufacturer, so I bought some premade stuff for a different boiler (twice as thick) and attached it to the inside. I also, bolted the bracket into place.

    Shortly thereafter I decided to repair the warped rear base panel, finding out the manufacturer sells them, even though the boiler is discontinued. I bought the base panel along with the insulation attached and installed it.

    The rollout switch temperature is now well below the limit, as expected.

    Now I am trying to get the single pipe system balanced. There are two insulated supply headers in the house, front (25 feet) and rear (15 feet). The uninsulated smaller returns are about the same length. The rear header heats up within a couple of minutes, but the front takes sometimes (like from cold iron) more than 10 additional minutes to warm up.

    I have tried changing the main vents from a Gorton #1 on the return line for each header to a Gorton #2 for each header, and adding a penetration on the far end of the front header insulated supply with either 1 or 2 of the Gorton #2s. Nothing has gotten the front header to warm up any sooner than about 5 minutes after the rear. The lone thermostat is in a room on the first floor front and the individual supply pipe to it barely get to steam temperature.

    I even ran one test with all radiator supply and vent valves shut to see if the front would heat up quicker. No significant improvement. I snaked the header from the new penetration back toward the boiler 25 feet of the 30 foot length and only got a slightly wet rusty colored water on the snake. No evidence whatsoever of any sludge.

    I am discussing the situation with one of the guys referenced on this web site, but he's 2 hours away and isn't available until December. I greatly appreciate his advice and hope something gets identified that can reduce the time lag.

    Any suggestions as to why this might be the case?

  • SteamingatMohawkSteamingatMohawk Member Posts: 251
    Now for the other issue. Occasionally, the first mixing tube/burner has the flame inside the tube. Last winter while dealing with the previously mentioned problems, my heating guys and I did a bunch of things to try to eliminate it, but it comes back.

    We removed and thoroughly wire brushed and vacuumed the mixing tubes. We removed the gas supply pipe that holds the orifices and found no evidence of blockage. We inspected the outlet port of the gas valve and found nothing. We also adjusted the gas pressure, which was high to 3.5 "w.c.

    I swapped the mixing tube (first - closest to the gas valve) with the furthest (fifth). It made no difference.

    When it happens, I use a soft copper wire in the orifice and the problem doesn't happen again for a while. I have only done this a few times and never did it before the flame in the tube problem occurred.

    I am wondering if something wacky, like static, is causing dust to accumulate on the orifice. But if that's the case why only the one nearest the gas valve.

    I am considering swapping the orifices to see if the problem moves before I just replace all 5 orifices, if that is a likely cause ($5.00 each).

    I intend to check the gas valve pressure, but prefer to have my heating guy there. I found a really neat manometer on the web that cost under $20. I will see how close it reads when I have my heating guy check the gas pressure. I don't like messing around with gas, for the obvious reasons.


  • The Steam WhispererThe Steam Whisperer Member Posts: 505
    Spider web inside orifice. Remove orifice and clean out. Putting a wire in will push it back, but gas pressure pushes is back forward. However, some boilers are just poorly designed and this tends to happen sporadically.
    To learn more about this professional, click here to visit their ad in Find A Contractor.
  • SteamingatMohawkSteamingatMohawk Member Posts: 251
    I came across an article, "Balancing Steam Systems, Using a Venting Capacity Chart" that has lots of good information in it, including an update titled, "Can you vent too fast?" On the second page the authors mention that they removed Heatimer Varivent valves because they have large capacity and replaced with another brand. Over venting is an interesting concept and I may be in that situation.

    A few hours later, I had a discussion with the guy I mentioned above and he is highly familiar with the article. What a coincidence! Anyone struggling with venting can probably benefit from the article. Particularly important to me is a pretty extensive table of vent valve capacities, showing how one manufacturer's identification system/models matches others. It would not be appropriate to provide that detail in this forum. Just Google the above title and you should find it. If you do not, reply here and we can communicate separately on how to get there.
  • SteamingatMohawkSteamingatMohawk Member Posts: 251
    I replaced 6 of my 9 vents and was amazed. I am almost there, I have 3 more valves with orifice sets coming. They do not seem to be available locally, so I had to order via internet. Once I get them, I will replace the last three then fine tune the system. Success may be a few days away!!
  • gfrbrooklinegfrbrookline Member Posts: 610
    If you are still looking for a thermostat with wireless sensors that can control multiple zones the honeywell visionpro 8000 can. I have it on my one pipe system and have 6 sensors, one in each apartment that average the temperature of all sensors to run the building. They are also capable of controlling zones.

    What vents did you use for the radiators? I am hoping Ventrite No. 1's, Gorton's, Hoffman's or Maid o Mist and not the ones from the big box stores. If you had varivents I would replace them with Ventrite No. 1's or Maid o Mist 5A since they are the easiest to adjust. I used them to balance my building then replaced them with corresponding venting Gordon's so the tenants can't screw the balance up.

    Only use TRV's as a last resort and if you have tenants I would only use the Danfoss that has a vacuum breaker and has landlord controls that let's you set the minimum temperature that it can cut in. Set that to the Tstat temp . If your system is balanced which it should be before you should even consider TRV's, this will prevent the tenants from being able to shut the radiators off and making your boiler be overrsized and run on pressure.

    I would swap the main vent on your 25' main out with a Barnes and Jones Big Mouth. It will help balance your mains.

  • gfrbrooklinegfrbrookline Member Posts: 610
    I was just thinking about the advice I gave with the TRV's, I would set the low limit one degree below the Tstat and the high limit to 1 degree above, that way it will mirror the rest of the radiators and be within tolerances. If you have the correct venting you shouldn't need TRV's.
  • SteamingatMohawkSteamingatMohawk Member Posts: 251
    I removed all my Varivalves and installed Maid O'Mist with swappable orifices. 6 of the 9 were bought with the swappable orifices, which I had to buy over the internet. I could not source just the orifices, so I called Maid O'Mist and the representative said they are hard to find. She said she would send me a few sets; that was a week ago and they have not arrived. She also gave me the name of three well known distributors; none listed the orifices on their web site.

    In any event, I found some remarkable information in the table I mentioned above about the capabilities of the different manufacturers' vents. Vent Rite 1s can be throttled slower than a #4 venting capability, but not faster than a #5. Varivalves at the minimum setting are about a #5, all the way up to between a #1 and #2. I used Varivalves under the mistaken impression that "SHUT" meant they did not vent anything. I now know better.
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