Vision or Tekmar for Outdoor Reset

Tom Giedraitis

I have a 140M Munchkin with Superstor Indirect. It's serving 2 radiant zones and a high temp zone for the rest of the house.

I would like to have Outdoor reset control installed to modulate the temp of the high temp loop. Must this be done with a Vision Package or can it also be done with a Tekmar package? My installer is more comfortable with the Tekmar Controls, but I was under the impression that a Vision package had to be used with the munchkin.

True or False, and if false, which Tekmar package should I be looking to have put in.

Thanks

Plumbob

Vision

The Vision package is built into the Munchkins; all that you pay extra for is some connectors and documentation.

In principle Vision is better than a typical external controller. A standard Tekmar model would control the temperature by on/off, so you lose the ability to modulate the burner. It will work, but not as efficiently.

A new Tekmar, the 263, has an analog output to use in modulating the burner, and the appropriate part to let the Munchkin connect to it (P125) can be obtained from HTP. Your contractor may be unfamiliar with this and so may not want to do it, but Tekmars have many advantages, including nonlinear reset curves that match the characteristics of your emitters. Another advantage is that the Tekmar documentation is freely available, while the Vision documentation is not routinely provided to homeowners. The idea is that if you want to change the reset curve, you pay your contractor to come to your house and do it! The Vision system is not as well designed or intelligent as Tekmar firmware is...it is clear that the Tekmar people have more experience.

Anyway, A Tekmar 263 is the best choice, followed by the Vision package. A general purpose Tekmar model (such as the 256) is worse than Vision because of loss of the modulation feature.

Jay_12

Munchkin P125 control

The tekmar 263 requires a specific Munchkin control board called the P125. Please contact HTP if you are unsure of which control board your Munckin has installed.

How are the radiant floor temperatures being controlled? The radiant floors will feel much more comforable if you use a mixing outdoor reset control (since the Munchkin will be operating at higher temps for the baseboard). I would suggest using a 360 with mixing valves or a 361 with variable speed injection pump.

If you have any questions, please call us at tekmar.

Jay www.tekmarcontrols.com 250-545-7749