High Pressure Control; Low Pressure Control; Heat Exchanger Heater Thermostat; Pressostatic Valve Kit (Optional) - Johnson Controls cwp series Installations- Und Wartungshandbuch

Control System

6.2 High Pressure Control

The high pressure control is a pressure activated
switch that opens on a rise in pressure. When the
switch opens, the safety relay de-energizes the com-
pressor circuit preventing the unit operation until the
high pressure control is reset.
The high pressure switch requires manual reset and
is factory adjusted to trip out at 28 bar.

6.3 Low Pressure Control

The low pressure control is a pressure switch activat-
ed by evaporator pressure. The switch opens when
the pressure decreases abnormally.
6.4 Heat Exchanger Heater
Thermostat
The evaporator heater thermostat provides freeze
protection down to -18 °C ambient temperature dur-
ing unit shut down periods.
It closes at +4 °C, activating afterwards the evapora-
tor heating cable.
On heat pump units, both evaporator and condenser
are equipped with electric heater cable and thermo-
stat to protect against freezing.
6.5 Pressostatic Valve Kit
(Optional)
This item is available only for cooling only units. The
pressostatic valve, controlled by condensing pres-
sure, regulates the water flow to maintain the con-
densing temperature at the desired value (the con-
densing temperature of +40 °C is recommended).
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