Dual vs Single Transformer Setup
Transformers! (Not a cartoon kind!)
The Smart Swamp Cooler board comes with an option of disabling the cooling side transformer and making the system run of the furnace transformer. Making it single transformer system!
Simply keep transformer jumpers for the Dual Transformer Setup or remove transformer jumper for the Single Transformer Setup on the Smart Swamp Cooler PCB. See picture below to locate transformer jumpers.
Transformer Jumpers
Dual Transformer Setup
The dual transformer system is powered by 2 transformers. One controlling heating circuitry and the other one controlling cooling circuitry. Such a setup requires keeping power signals separate. Furthermore, you have to keep cooling signals separate from the heating signals. When those control signals are enabled, they will be enabled using voltage coming from the transformer they are assigned to.
You might ask - they are both 24 V so why can’t we mix those signals? They are 24V but they are alternating current 24V! So, the issue is not the voltage but the phase. You could potentially connect the 2 if they are perfectly synced but it is highly unlikely that they will be synced. Meaning that one transformer might be at 24 V at a particular moment in time and the other might be at a different voltage, let say 0V or -24V. Connecting the 2 would force the current to flow from one transformer into another and potentially damage cooling and/or heating circuitry!
DO NOT
Remove transformer jumpers on the Smart Swamp Cooler PCB
Connect Rc and Rh together!
Connect Cc and Ch together!
Connect the heating signals to cooling signals and vice versa!
DO
Keep the cooling and heating signals separate
Dual Transformer Setup example (Source: Sensi By Emerson)
Single Transformer Setup
Single transformer setup is powered by a single transformer which makes it more flexible! You do not need to worry about different voltages because there is only one powering voltage. In such a setup it is okay to connect cooling and heating signals together. But you do have to worry about powering the Smart Swamp Cooler board using a furnace transformer.
This option might not be available to you if you have an older furnace that comes with only 2 signals – W and Rh at the thermostat (Option C). Maybe there is still hope, check your furnace connections (Power down the furnace before accessing the furnace control electronics!) and see if it has unconnected signals (such as C and G). If that is the case, you can rewire the thermostat cable to carry more signals by replacing 2 strand cable with 5 strand thermostat cable!
DO NOT
Use 2 strand thermostat cables
Forget to provide power to the Smart Swamp Cooler PCB
DO
Remove transformer jumpers on the Smart Swamp Cooler PCB
Connect Rc and Rh together!
Connect Cc and Ch together!
Connect certain cooling and heating signals if needed by your application
Single Transformer Setup example (Sensi by Emerson)
