22
/04.2016/
G35
EN
4.6 Motors
Fans
Fans are radial, EC (electronic commutation) type, with backward curved blades made of galvanised sheet steel.
Rotor is also made of galvanised sheet steel, mounted on ball bearings and dynamically balanced according to DIN
ISO1940, quality level G6.3. Protection degree IP54. Insulation class B.
2-way modulating valve servomotor (CW units)
Power supply 24 V AC 50/60 Hz. Absorbed power 1 W at nominal torque. Control signal 0÷10 V. Running time = 90
s for an angle of 90°. Protection class III, IP54 protection degree.
4.7 Control, monitoring and safety components
All unit components are factory adjusted and generally do not require further adjustment. If, for special reasons,
it becomes necessary to change the settings of the automatic devices these changes must only be performed by
experts and only after informing the STULZ engineering division department.
STULZ conditioners are equipped with a set of devices designed to ensure proper operation. Trip-
ping by any one of these automatic safety devices is a sign of a malfunction and it is absolutely
necessary to eliminate the cause.
It is forbidden to electrically by-pass the safety devices. Doing so, in addition to being dangerous,
also immediately invalidates guarantee coverage for the product.
Isolate the system from electric mains before performing any repair or maintenance work.
Work on the units must only be done by qualified and authorized experts.
High pressure switch (A, AS, GS, GES units)
This stops compressor operation whenever pressure inside the refrigerant circuit exceeds 36 bar. When pressure
returns below 29 bar, alarm signal from high pressure switch is disabled.
Temperature sensors
Three PTC and three NTC temperature sensors are connected to analogue inputs of electronic controller, in order
to measure following parameters:
• 3 return air sensors (TRA, TRB, TRC), placed behind air intake opening - higher, middle and lower part. They are
NTC type connected to C7000 controller
• 3 supply air sensors (TIA, TIB, TIC), placed on frontal panel - higher, middle and lower part. They are PTC type
connected to C7000 controller
On AS, GS and GES units: two additional NTC temperature sensors are placed on the suction and discharge side
of compressor and connected to the driver of the compressor and the electronic expansion valve. The sensor on the
suction side transmits a signal to the μPC controller for the management of the expansion valve. The sensor on the
discharge side is used to check whether the compressor works within the envelope.
On GS units: one additional PTC sensor, connected to C7000, measures the temperature of water supplied to the
condenser. This signal is used by C7000 to check anomalies in cooling circuit of the condenser.
Pressure transducers (AS, GS, GES units)
Two pressure transducers are installed on the suction and discharge side of the compressor to check whether the
compressor works within the envelope.
