Posted by Harold Kestenholz - Hydronic Network on November 18, 2001 at 11:48:27:
In Reply to: operating temp of boiler posted by David Johnson on November 17, 2001 at 19:54:24:
The water temperature needs to be warm enough to provide enough heat to keep you comfortable. This can be anywhere from 90F to 240F, depending upon the output of the radiation and the weather. As the weather changes and you notice the room is not getting to 68F or so, move the dial up 5 degrees until the weather is as cold as it gets. That is the maximum temperature you need. There is also a control you can install called an outdoor reset control that will do that sutomatically.
You may not need a low limit/circulator control at all. The circulator can start when the thermostat calls for heat. My circulator has been running for 20 years now, stopping only when I do boiler circuit changes every few years.