Controlling Hydronic Radiator Panels

[HeatFarmer]

So as I'm putting panels in each room, linked to a manifold via home runs, I am perplexed by the 3 or so solutions to how to regulate the heat which have been suggested to me.
My initial thought was to throw a mixing valve on this secondary loop, pull through with a variable speed pump and be done. Temperature control would be via the Thermostats at each radiator. Perhaps a Tekmar 156 set point control or something similar to turn the pump on and off, at given temps, but basically a wide open system.
Another solution would be to still have a mixing valve, but set it a bit higher...say 160 or so and then use a Tekmar 356 or similar to control the pump. This is starting to get pricey though.
Another thought is to use an actuator instead of a fixed mixing valve. Control it with something like the EM-32 (broken link removed to http://www.hydronicalternatives.com/EM-32_Installation_instructions-2010-04-01.pdf) and use a set point control to turn the pump on and off, again, based on outdoor temps.

Is this overcomplicating things? I need something which I can set up and have run without the need to mess with it. And, as costs on my system spiral out of control I am looking for ideas on how to make this work and keep the costs down.
Any ideas or solutions out there from those who are using radiant panels?

 

[ewdudley]

Simple and effective would be a variable speed, pressure controlled ECM pump with wax heat-motor regulators on each bank of emitters.

Here's an article that discusses:

http://www.google.com/url?sa=t&rct=...jtnsAQ&usg=AFQjCNH43lNJbVGc1cVQHLQNN3dSRqaGyQ

 

[HeatFarmer]

Thanks for the link Eliot! That article is describes exactly what I figures should happen....run the a smart, variable speed/variable pressure pump to circulate the water to the radiators, and use the thermostats on each radiator to control individual room temperature..... the only difference in my system being that I will need to temper the water from storage down a bit with a fixed temp mixing valve. What I really need then is some controller to kick the circulator pump on when the outdoor temperature reaches a certain minimum and kick it off when it hits a maximum. What would be even better is if this controller could cycle the pump more or less given a range of temps. IE, in the spring or fall the pump kicks on during a chilly day once or twice to take the chill off the rooms and then as the sun sets and temp drops kicks on more or less full time--due to the nature of individual in-room thermostats at each radiator it doesn't make sense to control this function via an indoor thermostat places statically in the house--which room?--but base it on a function of the outdoor temp. Not sure if there is a controller which does this, or if a set-point and some imagination is all I need.....

 

[HeatFarmer]

As I look into it, I am thinking maybe a Tekmar 256 http://www.pexsupply.com/Tekmar-256-Boiler-Control-One-Stage-Boiler-4150000-p might be the way to go....it has outdoor reset, and can monitor the temperature of the lines to the radiator manifold. If it can control the pump then it would probably work.....

 

[willworkforwood]

If your loop is in the good part of the Grundfos Alpha curve, wouldn't that be a perfect fit? Auto mode, always on - no controller needed?

 

[HeatFarmer]

Willworkforwood....thanks for introducing me to the Alpha! It is now the pump of choice for this leg of the system..... I like it's features and it should cut out lots of headaches. I still think I want a seasonal on/off for the pump though, so we don't have to remember to kick it off in the middle of summer and turn it back on in the middle of a cold night.....I'd just like it to work as transparently as possible, so we don't have to explain the system to the kids, other family members or house-sitters.