Bi2: Condensate Overflow; Bi3: Occupancy Or Generic Binary Input - Trane Tracer ZN511 Installation And Operation Manual

CNT-SVX06B-EN
Binary inputs for water-source heat pump applications

BI2: Condensate overflow

The function of condensate overflow is to prevent the condensate drain
pan from overflowing and causing water damage to the building. If BI2 is
wired to a condensate overflow switch and the level of condensate reaches
the trip point, the Tracer ZN511 will detect the condition and generate a
Condensate Overflow diagnostic.
Note:
On some heat pumps, the condensate overflow switch may be a
safety wired in the safety circuit (see Figure 5 on page 17). For
the Tracer ZN511 to generate a Condensate Overflow diagnos-
tic, the condensate overflow switch must be removed from the
safety circuit and wired directly to BI2. If the application does
not warrant the use of BI2, configure the input as Not Used.
Diagnostics for this function will not be generated; however,
units with a safety circuit containing a condensate overflow
switch will maintain their existing level of condensate overflow
protection.

BI3: Occupancy or generic binary input

The function of occupancy is to save energy on unit operation by changing
room set points when the zone is unoccupied. BI3 is used for two occu-
pancy-related functions. For stand-alone controllers, this binary input can
be wired to a binary switch (occupancy sensor) or time clock to determine
the occupancy mode—either occupied or unoccupied. For controllers
receiving a BAS-communicated occupancy request, the function of BI3 is
to change the mode from occupied to occupied standby. (For more informa-
tion on occupancy-related functions, see "Occupancy modes" on page 26.)
BI3 is the only input that can be configured as a generic binary input.
When configured as a generic binary input, it can be monitored only by a
BAS, and has no direct effect on Tracer ZN511 operation.
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