Carrier 42BC Series Technical Data Manual page 66

* If your Aquasnap unit (heat pump) is operating with chilled water
and heating is requested on the remote control (42B), its inside unit will
turn off the valve. However, if you set a higher setpoint temperature in
the thermostat, the control will enable the valve again, but the chilled
water will enter (as there is only one valve at the inside unit). Then, the
chiller will supply chilled water, generating discomfort since heating was
requested.
* The same precaution shall be taken for Aquasnap units (heat pump)
when they are operating for hot water and cooling is requested on the
remote control (42B): its inside unit will turn off the valve. However, if
the thermostat is set for a lower setpoint temperature the control will
enable again the valve. But the hot water will be entering (since there is
only one valve in the unit) and the chiller will be generating discomfort
because cooling was requested.
* The precautions above are important since the control of the
terminal unit does not control the chiller. If this function is required, we
recommend the use of units without control or the use of Carrier "Fan
Coil Controller" or other controllers of the CCN line.
Set your controller to the same operating mode of the chilled or hot
water supply unit (chiller).
This equipment must be connected to the main power supply with a
circuit breaker or with a switch with a contact separation of, at least,
3 mm.
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CATÁLOGO TÉCNICO / DATOS TÉCNICOS / TECHNICAL DATA - CT 42B 60Hz