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.

Boiler DHW and Reset Heating Settings

rafman Member Posts: 2
Hi, does anyone have any settings for their boiler they can share with me? We have and IBC Boiler VFC 15-150 with radiant floor heating.

I can't seem to get the temperature to lower on my thermostats in any floor of the house. It's just too hot all the time. Temperature is always at 75F and want to lower it, preferably at 67F. Any ideas? My settings for DHW and Reset Heating Loads are below. Thanks.

*DHW settings:
DHW Target Setpoint 175F
DHW Tank Setpoint 130F

*Reset Heating settings:
Indoor Set Point Temp 70F
Design Outdoor Temp 25F
Design Indoor Temp 75f
Design Supply Temp 125F
Summer Shutdown Temp 70F
Max Supply Temp 135F
Min Supply Temp 95F
Suppy Diff'l Temp 15F
Priority 35
Pump Purge Time 0s
Indoor Temp from Indoor
Outdoor Temp from Outdoor
Water Temp from Outlet
Mixing Temp from Mixing
Mixing Enabled Off
Value Full Swing Time 0s


  • mattmia2
    mattmia2 Member Posts: 9,412
    try changing your min supply temp to about 75-80.
    HVACNUT Member Posts: 5,740
    Design indoor temp 75F?
    Max supply temp 135F? What type of flooring? Staple up?
  • hot_rod
    hot_rod Member Posts: 21,846
    Same question, what type of radiant installation?

    What type of controls thermostats, zone valves?

    Could be you are not stopping flow, heat is constantly leaking into the radiant?
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • rafman
    rafman Member Posts: 2
    edited October 2022
    I should have mentioned its a high mass radiant system. Thanks for asking. I touched the red pipes (pic attached), they aren't flowing or warm.

    I have already lowered the Min Supply Temp yesterday to 80 but not much change. Maybe 1 degree change.

    Thermostats controls the zone valves.

  • Zman
    Zman Member Posts: 7,542
    I am guessing that your overshoot is caused by a combination of external gains like solar and reset curve being set a bit too high (flywheel effect). Keep tinkering with the curve, but consider that without cooling, you may need to live with some overshoots.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein