Outdoor Reset and Woodstove Combo

[AbeAinPa]

I have radiant floor heating in my house and the main control is an outdoor reset sensor. Heating is based solely on a combination of outside air temperature and boiler temperature, the internal temperature of the house is not part of the equation at all. The setup is very efficient for heating via the boiler only, but the problem is trying to use a wood stove in conjunction with this system. Since the heating requirement for the boiler is determined based on outdoor temp, it doesn’t “know” when the stove is on and keeps supplying heat. I manage this by turning back the set-point, but I was wondering if anyone had a solution requiring less human intervention.

 

[Nofossil]

That's an interesting problem. I've never actually seen a honest-to-goodness outdoor reset based system. I find it surprising that it doesn't take actual indoor temp into account. It seems like it would WAY overheat on calm sunny days, and let you freeze on windy nights.

Adding a second heat source would only complicate the situation in that case.

Seems like you need some additional feedback that says 'the house needs more heat' or 'the house is warm enough'. I've been playing with closed-loop control in which the outdoor temp is used to calculate a base assumption about required temp which is then modified by the difference between indoor actual vs. desired temps (an the integral of the difference over time, but that's a different discussion).

Does anyone here know whether it's normal to ignore actual indoor temps in an outdoor reset system?

 

[harttj]

I installed outdoor reset control on my system this year. I have cast iron stand alone radiators. I bought a new old stock Tekmar variable speed injection controller from ebxx. I have it hooked up to the secondary loop pump to my house heat exchanger.

I have found it to work very well so far. Usually this time of year the house is too warm, but it does a good job of regulating the temperature. I do have a thermostat though. I've also found it to be more gentle on the temperature swings of the primary loop.

Tim

 

[barnartist]

Hijack alert...

Best place to purchase and learn about outdoor reset for my radiant system. I assume it uses its own mixing valve?