Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

2-pipe steam + ODR + coal stove?

Hi. I have a 100+ yr old 3700sq ft home w/2-pipe steam (burnham megasteam & fully insulated pipes). My plan (based on what I've been reading in this forum) is to install a tekmar 279 ODR w/TRV's to help eliminate the hot/cold swings in temp. The issue is, I also sometimes use an antique coal stove that easily heats the downstairs, but then at night the bedrooms are too cold. My question is, will the tekmar ODR still work correctly when the coal stove is on? My thought was that if I install indoor sensors upstairs in the bedrooms, and downstairs in a room furthest from the stove, that the averaged temp of all sensors would still allow a call for heat in all scenarios, regardless if the stove was on or not, and the TRV's would prevent overheating in areas that are close to the stove. My other idea is to just use TRV's and move the thermostat upstairs. What are your thoughts? Thanks!


  • Jamie Hall
    Jamie Hall Member Posts: 22,952
    I presume the idea is to use the Tekmar to control the cycle timing of the steam boiler, rather than having a thermostat call for heat and having the boiler cycle on pressure, if it cycles at all?

    Then use TR VALVES (not vents) to shut off the possibility of steam to various radiators? These valves would be, presumably, full port valves installed on the various risers or runouts?

    I have to admit that I'm not just sure what the Tekmar would contribute to the mix, besides some complexity. Thermostatically controlled valves on the steam lines leading to the areas which overheat when the coal stove is in use, plus shifting the thermostat upstairs so it can still properly control the boiler will work, although the boiler will be horribly oversized when the control valves are closed...
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • shanericciardi
    shanericciardi Member Posts: 4
    edited November 2018
    Yes. I wanted to use the tekmar for two reasons: 1. to make the house more comfortable in relation to outside temp, especially when the stove is not on. 2. if the stove is in use, i was *hoping* that the tekmar would see a higher average indoor temp and then fire the boiler for less time, thereby somewhat reducing the effect of the boiler being oversized when the TRV's near the stove are closed. I've never used one of these controls though, so I don't know if what I'm thinking is possible or not.

    Also - the TRV's would be the standard thermostatic rad valves. I've been looking at the Danfoss ones.