Tekmar Controls with Indoor Reset

d1222

Hello, does anyone have any experience with the latest Tekmar control systems that include indoor reset? I'm considering using them to control an IBC 15-150 condensing boiler (2 zones - one for whole house cast iron radiators and one for an air handler coil). I'm most interested in their ability to use indoor reset along with outdoor reset (to theoretically hold the temperature at the set point rather than how a traditional thermostat would overshoot the set point and turn off the boiler). I would imagine that it would work in a similar fashion to the Veissmann Vitotrol 300, correct? Does this system typically keep the boiler on at all times and simply adjust the modulation (10:1 turndown on the IBC) to raise or lower the water temperature to hold the set point on the thermostat? Any help would be appreciated.



Thanks

STEVEusaPA

Try this..

I have yet to use this Tekmar Boiler Control, so I couldnt comment.  But if you email Tekmar support and ask them all your questions.  They wont just "yes" all your answers, and tell you it will work great, they will take the time to fully understand whats going on, and make recommendations.

Zman

Tekmar

Tekmar products and support are excellent.

I agree with Steve that a phone call is in order. They also have some excellent essays on their web site that will give you some background info.



The idea with the TN4 and TN2 t-stats is that they keep track of trends in indoor and outdoor temps. They then "learn" over a period of time what the requirement are of each zone and make adjustments to the water temps. They are also quite good at modulating the boiler and adjusting the on/off differential to avoid short cycling.



When the zones have similar temps needs, the tekmar will pulse width modulate the zone valves or circs to get the correct average temperature. If one needs 130 degree water and the other 120, the tekmar will cycle the valve on the 120 loop to keep the average down.



In your case with 2 very different heat emitters, you may need a mixing control on the cooler zone (cast iron). The tekmar would provide the hotter water to the coil then mix down the water to the rads. When only the rads call for heat the boiler would fire to the lower temp and the mixer would go wide open.



There are also nice scheduling and home/away scenes built in if needed.



Carl