Explanation of MICROTherm Operation
The computer within MICROTherm times the last off-cycle and computes a percentage of that period (the economy factor) and then delays ignition of the burner by that calculated additional time. By constantly applying this percentage, the amount of delay varies according to the last off-cycle. As described in principle 2 above, longer off-cycles mean less demand and MICROTherm calculates longer delays. Shorter off-cycles mean greater demand and MICROTherm calculates shorter delays. With this design, MICROTherm (unlike any other control system) is always perfectly 'aware' of a building's heating requirement.
When the delay is complete, the burner is released to start and will remain on until the boiler reaches its high temperature or pressure setting. This on-cycle will be longer than it would without MICROTherm, but overall there is a reduction in the total on-cycle time (and energy usage) due to principle 3 above. Or thought of in a different way, given that in any chosen period the burner can only be on or off, if the off-time is increased then the on-time must logically be decreased.
By increasing the off-cycles, MICROTherm achieves longer but less frequent (20-30% fewer) on-cycles. Not only does this result in energy savings, it also results in less soot build-up, reduced emissions, reduced maintenance, and longer life for the boiler and burner. The extended off-cycles can reduce water temperature anywhere from one to six degrees, but at no time does this minimum reduction affect building comfort or cause condensation or thermal shock to occur in the boiler.
A thermal sensor is attached to the outgoing supply pipe to constantly monitor its temperature. Should the temperature of the water drop to a programmable low limit, perhaps due to a sudden increase in demand, the microprocessor immediately cancels any extended off-cycle, allowing the burner to ignite.
MICROTherm is wired in series between the operating control (frequently the aquastat) and the burner controls. In the unlikely event of product failure, a magnetic relay closes, returning the system to its preinstalled condition.
MICROTherm also has a watchdog technology that immediately shuts itself down in the event of power interruption, and will restart itself at its last programmed setting when correct power is restored. The circuitry incorporates surge-suppression and protection against most radiated and conducted electronic 'noise'. |
