4-pipe split mode is used for outdoor split systems that may be piped to two or more separate air handlers. A Y1 input call directly turns on C1, a Y2 input directly turns on C2, and so on. The parameter thermostat only control enabled and the parameter 4-pipe split enable must be set to yes.
The number of cooling stages and the number of refrigeration systems are both set to 2
When the control receives a Y1 call, it stages on the CN-FAN output for the outdoor fan. 3 seconds later, the C1 output energizes.
When the control receives a Y2 call, it stages on the CN-FAN output for the outdoor fan. 3 seconds later, the C2 output energizes. The number of cooling stages and the number of refrigeration systems installed must both be at least 2.
When the control loses the Y1 call, it de-energizes the C1 output. If C2 is off, the CN-FAN also immediately de-energizes. If C2 is energized, the CN-FAN stays on.
When the control loses the Y2 call, it de-energizes the C2 output. If C1 is off, the CN-FAN also immediately de-energizes. If C1 is energized, the CN-FAN stays on.
The number of cooling stages and the number of refrigeration systems are both set to 4
When the control receives a Y3 call, it stages on the CF2 output for the outdoor fan. 3 seconds later, the C3 output energizes. The number of cooling stages and the number of refrig systems installed must both be at least 3.
When the control receives a Y4 call, it stages on the CF2 output for the outdoor fan. 3 seconds later, the C4 output energizes. The number of cooling stages and number of refrig systems installed must both be 4.
When the control loses the Y3 call, it de-energizes the C3 output. If C4 is off, CF2 also immediately de-energizes. If C4 is energized, CF2 stays on.
When the control loses the Y4 call, it de-energizes the C3 output. If C4 is off, CF2 also immediately de-energizes. If C4 is energized, CF2 stays on.
Timing
If multiple Y calls are received at the same time, there is a 5-second interstage delay between the compressor outputs instead of the usual 30 seconds.