The Electric Heating System Basic Operation
On Fig. 2-2, electric heating system has more control than the main gas furnaces. Low impedance element used for heating draws a lot of current, so the main contacts should be of sufficient size for the current batch.
The thermostat closes and completes the circuit to the heating sequencer coil. Sequencer coil is heated by a bimetallic strip that leads key contacts to close. Once the main contacts are closed heating element in a chain and a 240-V line. Auxiliary contacts will also close at the same time as the main contacts. When the auxiliary contacts close, they complete low-voltage circuit to fan relay. Kiln fan will be turned on at this time.
After the thermostat was satisfied, he opens. This allows heating sequencer coil to cool down slowly. Thus, the main contacts do not open immediately remove the heating element from the queue. Therefore furnace continues to produce heat after the thermostat was satisfied. Bimetallic cools down to about 2 minutes as soon As it cools, it opens the main and auxiliary contacts, which removes the heating element from the queue, and stop the motor.
After the room cools below the thermostat setting the thermostat closes and starts the sequence again and again.
Basic Electrical Heating System
Electric fuel heat only heat produced almost as quickly as the thermostat calls for it. This happens almost instantly. No heat exchangers to keep warm. Heating elements begin production of heat moment thermostat calls for it. Various types of electric furnace fuel. They can be purchased in 5 - 35 kW dimensions. The outside looks almost the same as gas stoves. Heating elements are located in areas where heat exchangers are usually located. Because they draw a high-current, they require electrical controls that can take high currents.
The principle of operation is simple. In selector temperature of the thermostat is set to the desired temperature. When the temperature falls below this value, the thermostat calls for heat and causes of the first circuit of heating in the furnace be included. There is usually a delay of about 15 sec before furnace blower starts. This prevents from the fan circulates cold air in the winter. After about 30 seconds, the second circuit of heating included. Other circuits included one in a timed sequence.
When the temperature reaches the desired level, the thermostat opens. After some time, the first circuit of heating is disabled. The rest are closed one after another in a timed sequence. The fan continues to run until the temperature in the furnace falls below a certain temperature...