Hussmann proto-aire Installationsanweisungen
Protocol™ Installation and
Service Manual
Electronic oil regulators monitor oil levels. The units are powered by a 24V power supply.
When the oil level in the compressor drops below ½ sightglass, the fill light comes on and
the oil solenoid is energized. If after 90 seconds the oil level does not rise above ½
sightglass, the unit opens the compressor control circuit. If oil becomes available, the
control will re-set and the compressor will resume operation.
Auxiliary Systems
This form of sensor inputs can be programmed for analog operation (case temperature
sensor) or digital operation (such as Klixon). The auxiliary sensors are typically used to
provide information to control regarding a particular defrost circuit. The auxiliary sensors
can also be used to provide monitoring inputs from some external device; i.e. glycol
temperature, computer room thermostat, or pump station alarm relay closure.
It is important to remember that the auxiliary sensors, when used to provide information
regarding a particular defrost circuit, must be located in the correct defrost circuit lineup of
cases. Sensor A1 can only be used on Defrost Circuit #1. Sensor A2 can only be used on
Defrost Circuit #2. The same attachment of sensors to defrost circuits can be repeated for
A3 through A6.
NOTE: In the following examples, the #( ) refers to a defrost circuit and/or Aux sensor #
between 1 and 6. The same screens apply for all circuit and sensor attachments.
Temperature Termination (Digital Mode)
When an Auxiliary Sensor is used to connect a defrost termination thermostat (Klixon*)
device to the control in order to terminate defrost on high temperature, the following
information is required for proper operation.
(*No case temperature sensor present.)
Note: When temperature termination is Enabled, the control will automatically alarm on a
non-defrost mode contact closure from the defrost termination thermostat device. It is
assumed that while in refrigeration, the defrost termination thermostat (which is a close on
rise device) should be open.
Temperature Termination (Analog Mode)
In some applications of the Protocol™, there are not enough inputs to provide all the
information to the control for terminating defrost, alarming and monitoring purposes.
When this is the case, a temperature sensor and a defrost termination thermostat can be
wired in parallel at the case and then one cable run back to the Protocol™ control and
connected Auxiliary input. Under this application, the temperature sensor is used to
provide alarming and monitoring of discharge air while the defrost termination thermostat
provides the termination input.
When the oil level in the compressor drops below ½ sightglass, the fill light comes on and
the oil solenoid is energized. If after 90 seconds the oil level does not rise above ½
sightglass, the unit opens the compressor control circuit. If oil becomes available, the
control will re-set and the compressor will resume operation.
Auxiliary Systems
This form of sensor inputs can be programmed for analog operation (case temperature
sensor) or digital operation (such as Klixon). The auxiliary sensors are typically used to
provide information to control regarding a particular defrost circuit. The auxiliary sensors
can also be used to provide monitoring inputs from some external device; i.e. glycol
temperature, computer room thermostat, or pump station alarm relay closure.
It is important to remember that the auxiliary sensors, when used to provide information
regarding a particular defrost circuit, must be located in the correct defrost circuit lineup of
cases. Sensor A1 can only be used on Defrost Circuit #1. Sensor A2 can only be used on
Defrost Circuit #2. The same attachment of sensors to defrost circuits can be repeated for
A3 through A6.
NOTE: In the following examples, the #( ) refers to a defrost circuit and/or Aux sensor #
between 1 and 6. The same screens apply for all circuit and sensor attachments.
Temperature Termination (Digital Mode)
When an Auxiliary Sensor is used to connect a defrost termination thermostat (Klixon*)
device to the control in order to terminate defrost on high temperature, the following
information is required for proper operation.
(*No case temperature sensor present.)
Note: When temperature termination is Enabled, the control will automatically alarm on a
non-defrost mode contact closure from the defrost termination thermostat device. It is
assumed that while in refrigeration, the defrost termination thermostat (which is a close on
rise device) should be open.
Temperature Termination (Analog Mode)
In some applications of the Protocol™, there are not enough inputs to provide all the
information to the control for terminating defrost, alarming and monitoring purposes.
When this is the case, a temperature sensor and a defrost termination thermostat can be
wired in parallel at the case and then one cable run back to the Protocol™ control and
connected Auxiliary input. Under this application, the temperature sensor is used to
provide alarming and monitoring of discharge air while the defrost termination thermostat
provides the termination input.
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