To get email notification when someone adds to a thread you're following, click on the star in the thread's header and it will turn yellow; click again to turn it off. To edit your profile, click on the gear.
The Wall has a powerful search engine that will go all the way back to 2002. Use "quotation marks" around multiple-word searches. RIGHT-CLICK on the results and choose Open Link In New Window so you'll be able to get back to your results. Happy searching!
In fairness to all, we don't discuss pricing on the Wall. Thanks for your cooperation.
Need to contact us? Visit

High thermal mass control strategies?

JLJL Member Posts: 17
Does anyone have any ideas on controls foe high thermal mass? I came across a low mass atmospheric boiler with a high mass slab panel. It has been condensing most of its life partially due to the way it is piped and partially because of the application. I am going to add a primary loop with a four way motorized mixing valve with out door reset. Hopefully taking care of two issues, boiler perfection and adjusting supply temps to comfort zones with outdoor reset. In hoping the outdoor reset is going to help with the overshooting problem. Is there anything else I can do? I can't incorporate slab sensors but maybe there is some sort of retrofit slab sensor?


  • SWEISWEI Member Posts: 7,356
    Outdoor reset

    is the primary strategy, so start with that.  Consider the outdoor temp sensor location carefully -- you can do a lot with that, especially with solar gain.  Are there indoor heat sources like a woodstove or fireplace insert?  Consider zoning the affected rooms separately, using a thermostat as a high limit control for them.
  • ZmanZman Member Posts: 3,179

    Take a look at the tekmar TN4(or TN2) controls.

    It sounds like you need a combination of outdoor and indoor feedback. The tekmar will learn from past indoor overshoot and anticipate to some degree.

    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • jchjch Member Posts: 29

    Makes a couple of thermostats that you can specify either low- or high-mass with a switch. For high-mass it uses pulse-width-modulation to vary the amount of heat applied to the floors from the desired temp. Take a look.
  • JLJL Member Posts: 17
    Tn2 vs Tn4

    Yes. Looks like the tekmar indoor feedback with outdoor reset is the best thing to do.

    Do you know the difference between the tn2 and tn4? The only thing I can see is 2 wire vs 4 wire but I don't know what the extra two wires do?
Sign In or Register to comment.


It looks like you're new here. If you want to get involved, click one of these buttons!