Issue:

UC400 staged WSHP - BV15, Diagnostic: Compressor 1 Failure

Discussion:

What does WSHP binary value 15 mean?

What does Compressor 1 Lockout Status mean?

What does Compressor 2 Lockout Status mean?

BI2, binary input 2, Compressor 1 Lockout Status

BI3, binary input 3, Compressor 2 Lockout Status

BV15, binary value 15, Diagnostic: Compressor 1 Failure

WSHP Configuration:

This does not apply to the variable speed WSHP.

The Compressor Protection diagnostic will occur based on the status of the Compressor Lockout binary inputs, BI2 and BI3.

Binary input 2 is for compressor 1.

Binary input 3 is for compressor 2 and is only present in a 2 compressor WSHP.

There are safety switches measuring pressures and temperatures in line with the Compressor enable circuit.

If the pressures or temperatures are not correct, the switch will be open, and the compressor will not run.

When the switch is open, the binary input value will change from Normal to Locked Out.

And BV15, Diagnostic: Compressor 1 Failure, value will change from Normal to In Alarm.

See the wiring diagram below:

Compressor Protection Status (high or low pressure or freeze protection)

If the controller receives a compressor status off (binary input) when the controller
is trying to run a compressor, then a compressor status diagnostic will be
generated.  This failure can be generated by several possible
failures.  Once the diagnostic occurs, wait 30 minutes before turning the
compressor back on (the diagnostic is latched for 30 min). This is a non-latching
diagnostic unless it occurs 2 times in one 24-hour period.  Minimum compressor
off times are observed. If there are 2 compressors and only one is locked out,
the other compressor will be allowed to run on GE and EX series WSHPs. If both
compressors have compressor protection status diagnostics then the unit shuts down.

Partial wiring diagram for a 2 compressor WSHP

Notes:

This does not apply the variable speed WSHP, only the 3 configurations listed above.