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.

spitballing: thermostat solution for a floor-only Cross Manifold install

mthmlf84 Member Posts: 27
hey guys,

so I recently installed a triangle tube 199 combi in a 2750 sq ft ish 3 story house with 10 zones of staple up pex radiant floor. Up until now we were just pumping into 2 zones/stats: 1st floor zones 1-5, second floor zones 6-10, which was a temporary setup to get the system going.

Now I'd like to put a 10 zone cross manifold in and zone it properly instead of heating an entire floor or nothing, and I'm trying to figure out the thermostat part.

solution 1 would be to run a radiant floor thermostat to every room and a probe to every ceiling, which sounds complicated.

solution 2, I'm not sure, but I was thinking of setting up a "command center" where I could have a little closet on the wall just above the basement where the manifold is located and have 10 devices, one for each zone, monitoring the water temp going into each zone and turning them on and off as needed. could those devices be simple aquastats? as far as i understand, the thermostat only measures ambient temp and opens or closes a circuit according to demand. Are there standalone aquastats I could program to do just that using the pex pipe's temperature? any ideas?

ps: also, do my pump/flow requirements change if it's valve zoned vs two 5 loop zones as it is now (see pic)?



  • hot_rod
    hot_rod Member Posts: 20,826
    How many zones are you trying to end up with? I doubt you need a control on every port of the manifold, 10 zones?
    What about SWT required for the various zones? Looks like you have a 2 temperature system.
    Is the boiler running on ODR? The lower temperature zone SWT is fixed by the thermostatic valve?

    Too much zoning and micro-zoning can lead to boiler short cycling. How many zones or loop are on your mixing valve?

    At the vary least I think you want to know air temperature in the rooms or zones. Floor temperature sensors may be helpful in some areas, small rooms like bathrooms, for instance. The goal is occupant comfort, more-so than knowing RWT.

    You might just consider an electronic radiant specific wall stats or sensors like the tekmar or HBX.
    Wireless stats be an option also.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream