View Full Version : variable speed injection for radiant
01-04-2012, 01:31 PM
My plumber installed a brand new Buderus oil fired boiler with a Logamatic R2107 controller and FM241 bd for secondary low temp radiant heating. The system consists of a primary/secondary loop with an injection pump into the secondary low temp radiant loop. What he did not realize is that the FM241 can only control a mixing valve and not control the speed of the mixing pump. He is not suggesting to use a Tekmar356 to control the speed of the mixing pump instead of installing a motorized mixing valve. Any issues with this solution. Tks.
01-04-2012, 07:32 PM
I would use the Tekmar as, i assume, it is all installed. As an option get a 3 or 4 way mixing valve, use the buderus control and call it a day. You still have the higher temp for the primary heat, whatever that will be.
01-25-2012, 02:32 PM
its 50/50. Pay for the new control, which will work fine, or go with the mixing valve. I think the plumber should put in the mixing valve, and pay for the labor, or buy you the tekmar, it was his oversight
01-28-2012, 11:10 PM
Using v.s. injection may require re-piping and an additional circ. It is, however, the best method of controlling a radiant slab.
01-28-2012, 11:16 PM
Second attempt to attach file.
01-29-2012, 09:19 AM
If you follow the Tekmar PDF, take special note, and follow, the piping notes regarding spacing, how many pipe diameters from elbow, etc.
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