heat exchanger. Low flow rates as well as no water flow will activate the water flow
switch, the unit will shut down. The LED controller will display "EE3" if the water
pressure is insufficient.
High / Low Refrigerant Pressure Switches
• The high-pressure switch detects the refrigerant pressure in the sealed
refrigeration system and shuts the heat pump down when unsafe operating
pressures are reached. The heat pump will automatically reset after the system
pressure drops back to normal operating pressures. When this switch is tripped,
digital display will read "EE1"
• The low-pressure switch detects the refrigerant pressure in the sealed refrigeration
system to protect certain conditions that could be detrimental to compressor life. The
switch shuts the unit down when refrigerant leakage or insufficient refrigerants. The
switch automatically resets when the pressure rises to normal operating pressures.
The display will show "EE2" if this switch is tripped.
Low Ambient Temperature
If the air outside the heat pump is not warm enough to generate heat, the system will
shut down. The actual shutdown temperature point of your unit will vary subject to
current weather conditions and the amount of sunlight reaching the heat pump due
to low temperature. The shutdown can occur anywhere within a wide range of
temperatures, usually below 0 degree. A shutdown occurs when the air temperature
sensor
detects
the
ambient
temperature
is
lower
than
0
degree (digital controller will display a code "PP7"). The unit will start up again when
the temperature raises enough to reset this switch.
Time Delay
All models use a 3-minute time delay to prevent repeated tripping of the compressor
thermal overload, which is caused by attempting startup before system pressures
are equalized. Any interruptions, except of power loss, will result in a 3-minute time
delay.
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