(206) 949-5683, Top Rated Plumber, Seattle
Results 1 to 15 of 23

Thread: Hydronic radiant thermostat

Hybrid View

  1. #1
    DIY Junior Member birchlake's Avatar
    Join Date
    Jan 2012
    Location
    Melrose, MN
    Posts
    25

    Default Hydronic radiant thermostat

    Last fall, I built a small 5 room 1008 sq. foot patio home. Single level, slab on grade with hydronic radiant heat supplied by an Electro Industries 9kw mini boiler (model EMB-H-9). The entire house is on one zone. The home is located in Minnesota. I use a ductless mini-split for heat in the spring and fall and the hydronic heat for the coldest weather.

    The hydronic system is currently being controlled only by the slab sensor using a Ranco single stage Electronic Temperature Control unit.

    I love the in floor heat, but the one thing I am not crazy about is having to program the Ranco control unit slab temperature sensor setpoint frequently throughout the winter whenever there is a significant weather change. If I fail to do so, it results in either the air temperature of the house being too cold or too warm. This was particularly obvious when I left on vacation for a week and when I came back the outdoor temperature had risen significantly and because no slab setpoint changes were made during my absence, that resulted in a very warm house upon my return. And of course, extra energy consumed.

    The installer of this system had originally told me that air thermostats are not a great way to control hydronic radiant systems because of issues like passive solar gain, overshoot, undershoot, etc. I kind of get that, but after Google searching and seeing frequent nods towards Tekmar controls, it appears that they manufacture stand-alone thermostats that utilize floor slab temp input plus the air stat input TOGETHER, along with the ability to control minimum slab temperature. I was wondering if a stat with the ability to control these three things instead of simply slab temperature might not be a better choice for my application.

    In hindsight, I know that it would have been better if the system would have been designed with more sophisticated controls like a whole house unit and outdoor reset control, etc. But the house is built and my budget does not allow for a major upgrade at this time.

    So while I do realize "optimum" and "budget" don't go well together, my question for you guys today is this:

    If I replace the Ranco slab temp control with a more sophisticated hydronic thermostat like a Tekmar 552 and one of their slab sensors, do you think that would "improve" my control? I'm not looking for specific room control; I am fine with one stat for the entire house. If I feel that I have a shot at "improving" my control, I'm willing to try it. And I thought it would be best to get one of their higher end stats that would integrate with their whole house control unit network in the event that I am still not happy and want to make further upgrades down the line..

    If any of you have any experience with Tekmar or can make any specific recommendations for my application that would be much appreciated!
    Last edited by birchlake; 05-08-2012 at 04:18 PM.

  2. #2
    In the Trades Tom Sawyer's Avatar
    Join Date
    Nov 2010
    Location
    Maine
    Posts
    2,937

    Default

    Go with the Tekmar set up. It is much more accurate and you will be happy with the results.
    [B]No, plumbing ain't rocket science. Unlike rocket science, plumbing requires a license[B]

  3. #3
    Master Hot Water Mpls,MN BadgerBoilerMN's Avatar
    Join Date
    Mar 2011
    Location
    Minneapolis
    Posts
    285

    Default

    Most radiant floor heating installers know precious little about radiant floor design. The vast majority of radiant floor heating systems we design and/or install here in Minneapolis employ a simple air sensing thermostat for perfect control and comfort. Slab sensors are strictly for advanced radiant floor designers, the people you should start with before you buy your first foot of PEX.

    http://www.badgerboilerservice.com/helpme.html

  4. #4
    DIY Junior Member birchlake's Avatar
    Join Date
    Jan 2012
    Location
    Melrose, MN
    Posts
    25

    Default

    Thanks for the input guys.....

    Tom Sawyer, from my research, Tekmar seems to be one of the top dogs in hydronic radiant controls. When you said go with the Tekmar setup, do you mean that the Tekmar stat alone will be an acceptable improvement over what I currently have?

    Badger, I agree with you that my system was not designed optimally. I checked out your website; looks great and a lot of good information in there, but starting fresh is not an option for me. My mini-boiler is adequate for my house, I'm just looking to get a little better control of it.

    So what I'm specifically looking for comment on is this guys....................

    I am considering installing a Tekmar 552 thermostat and sliding one of the matching Tekmar slab sensors into the conduit into my cement slab (there's room in the conduit) so I can set a min/max floor temp. Will this be an improvement in my control?

    Link to the Tekmar stat I'm looking at....

    http://tekmarcontrols.com/zoning/552.html
    Last edited by birchlake; 05-07-2012 at 10:10 AM.

  5. #5
    In the Trades Tom Sawyer's Avatar
    Join Date
    Nov 2010
    Location
    Maine
    Posts
    2,937

    Default

    Yes, that is what you want
    [B]No, plumbing ain't rocket science. Unlike rocket science, plumbing requires a license[B]

  6. #6
    DIY Junior Member birchlake's Avatar
    Join Date
    Jan 2012
    Location
    Melrose, MN
    Posts
    25

    Default

    Quote Originally Posted by Tom Sawyer View Post
    Yes, that is what you want
    Thanks Tom.

    Along with input here, in the last couple of days I talked to applications specialists at both Tekmar (hydronic radiant thermostat supplier) and Electro Industries (mfg. of my mini-boiler) to see what they thought.

    Electro Industries said that they have had many customers using Tekmar thermostats with this mini boiler with good results. Tekmar also thought I would be happy with the improved control using the Tekmar 552 thermostat which has an integral air stat, uses input from the floor stat and allows me to keep a minimum slab setpoint temperature.

    Both Tekmar and Electro Industries reminded me that while use of an "outdoor reset control" would be optimum, what I intend to do should be quite an improvement over just using a slab stat.

    So I will be purchasing the Tekmar 552 and the matching Tekmar slab sensor and we'll see how it goes. Worth the $210 investment for improved control. I'll let you know the results, but will be next winter until I know!

    Thanks for the input guys.....

Similar Threads

  1. Help with hydronic radiant heat
    By alfpark in forum HVAC Heating & Cooling
    Replies: 29
    Last Post: 05-29-2012, 07:00 AM
  2. Indicator light on thermostat of a hydronic heating system
    By gdave in forum HVAC Heating & Cooling
    Replies: 1
    Last Post: 02-02-2011, 09:41 AM
  3. pressure and hydronic radiant heat
    By rrekih in forum HVAC Heating & Cooling
    Replies: 1
    Last Post: 11-30-2009, 12:15 PM
  4. Hydronic radiant heat stat
    By crater in forum HVAC Heating & Cooling
    Replies: 23
    Last Post: 10-31-2008, 03:05 PM
  5. Hydronic radiant floor heat
    By crater in forum HVAC Heating & Cooling
    Replies: 35
    Last Post: 03-03-2008, 12:18 PM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •