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Outdoor Reset Curve and Thermostat Settings

smithfan Member Posts: 91
I've finally have got my Outdoor Curve dialed in my mod/con boiler for this upcoming winter. The boiler heats two upstairs fin/tube zones and 1 basement in-floor heat slab. The slab heat zone is preceeded by a mixing valve in the plumbing to keep things under 120F there.
Before the upgrade to my boiler, I had installed Honeywell programmable thermostats for the 2 upstairs zones. The basement is a honey digital NON-programmable stat. The last thing I want to make sure is correct is the correct CPH or Cycles Per Hour setting for each thermostat. I won't be using much setback now that I have the ODR installed, however I want to make sure the CPH for each stat is correct. Currently the 2 upstairs are set to 3 CPH and the downstairs is set to 1CPH. Any insight into this would be appreciated!!


  • Ironman
    Ironman Member Posts: 6,868
    edited September 2015
    I'd set the two upstairs to 1 or 2 CPH and get a Tekmar 518 for the slab. The 518 is designed for radiant floors, the Honeywell is not. I would also get a smart valve with ODR controlling the water temp to the slab as it's bound to overheat with a fixed temp (dumb) mixing valve.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • Paul48
    Paul48 Member Posts: 4,469
    You've made the preliminary settings. You dial it in, this winter, by cranking the thermostats all the way up. When all the zones stay comfortable, regardless of what the outside temperature is, it's dialed in.