by Ron Walker
Parallel Circuits
The other type of circuit you will encounter as an HVAC Technician is the parallel circuit. These types of circuits are common to all of the equipment you will encounter. Most loads use line voltage as their power source. The parallel circuit allows the line voltage to be supplied to from the main power source. A parallel circuit allows the line voltage to reach all loads in the circuit. Each load must be either connected directly to the line voltage or in parallel with another load to supply the load with the full line voltage
Series Parallel Circuits Series parallel circuits are a combination of both the series and the parallel circuit. In heating, air conditioning and refrigeration equipment, these circuits are used to combine control circuits with the circuits that supply line voltage to the loads. Figure 4 shows a basic series parallel diagram. Notice our wall plug symbol has now been replaced by L1 and L2 which indicate Line voltage connections.
Parallel Circuits
The other type of circuit you will encounter as an HVAC Technician is the parallel circuit. These types of circuits are common to all of the equipment you will encounter. Most loads use line voltage as their power source. The parallel circuit allows the line voltage to be supplied to from the main power source. A parallel circuit allows the line voltage to reach all loads in the circuit. Each load must be either connected directly to the line voltage or in parallel with another load to supply the load with the full line voltage
Series Parallel Circuits Series parallel circuits are a combination of both the series and the parallel circuit. In heating, air conditioning and refrigeration equipment, these circuits are used to combine control circuits with the circuits that supply line voltage to the loads. Figure 4 shows a basic series parallel diagram. Notice our wall plug symbol has now been replaced by L1 and L2 which indicate Line voltage connections.
Fig. 3
Notice how all of the loads (CFM 1, CMP, C, and CFM 2) are all connected in parallel and are supplied with the full line voltage. Also note the various switches (LPS, HPS, THER, and CFM 2 THER) are connected is series with the loads. If any of the switches should open then it only removes power from the load directly in series with the switch.
If you notice in the figures above, we use symbols to represent the different components in heating, air conditioning and refrigeration equipment.