Systems Controls & Instruments CEM-24 Series Owner's Manual page 6

3.2 Connections for all applications
Notes: 1. Connection to 2-wire Millivolt system is used only in HC configuration!
2. Be advised that the turn on time for the LCD to light up is up to 10 seconds from
the time 24VAC is applied.
3. Emergency Heat (Heat pump configuration only)
In Auto mode (in Heating), Compressor runs 1st stage and EMH runs 2nd stage (W2+Y2).
Both W2 and Y2 stop at the same time.
In Heat mode, only EMH (W2) runs and the compressor is not active.
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