By: pvolcko On: Wed Dec 20, 2006 1:31 am
First, Ericjack:
The coal-trol offers the option to you of selecting a max and a min feed rate. If you're uncomfortable with level of fire and heating you're getting at a max burn rate, you can reduce it as you see fit. Also, the way our control works, it will not automatically call for 100% feed rate (or whatever your max is set to) when the temperature is below the setpoint like standard thermostats do. Instead we will ramp up slowly (larger differences between temp and setpoint will ramp more quickly). In this way a setpoint change can often be accomplished without hitting full burn, particularly on these warmer days or in well insulated (and good air circulation) houses.
Second, Paul: If you see that happen again (it is at FR 0, but the stoker/feeder is still chugging away for more than 2 seconds or so every 1 to 2 minutes) please call us. That shouldn't happen.
Lastly, for everyone:
Once settled to a new setpoint the control will maintain a +/-1 degree temperature range. On setpoint changes, though, it can take a while for the new setpoint to be met (as with any thermostat) and in many cases there can be slight to moderate overshoot. 2-5 degrees is not uncommon and usually will not last for very long. In rare circumstances larger overshoots have been reported. Usually this indicates an installation problem (very poor air circulation/heat transfer, improper thermostat positioning, etc.). If everything is installed properly, though, then it can sometimes help to use the HLF (Heat Loss Factor) setting. Changes to this should be one tick at a time and each adjustment should be tried out for at least a couple days to see how things respond. This may not solve your problem in which case we encourage you to call us so we can try to trouble shoot your problem and suggest some solutions. We prefer to do these things over the phone as they can take some time and involve a lot of questions and answers going back and forth.
We do recognize that minimized overshoot is the preferred function of any thermostat and we're continuing to improve the software in this regard (and others), as always. Unfortunately there are tradeoffs for minimized overshoot that make this problem difficult to solve perfectly and without complex setup proceedures.
This feedback is very useful in getting better control implemented and we're grateful to everyone who posts here with their experiences.