NANO Precision NPC 015, Service Manual

Page: 30 / 42

28
The data inside this manual are not binding and they can be modified by the manufacturer without notice. All rights reserved.
NPC 015 TO 230
8 . 4 F a n s p e e d r e g u l a t i o n
The fan speed regulation can be carried out by means of a pressure switch (FP).
1. Fan pressure switch (FP)
In these units a pressure switch detects the refrigerant compressor outlet pressure and controls the fan operation powering them on or
off.
The pressure switch FP is screwed to the refrigerant circuit piping with SCHRAEDER valves (with needle) which prevent leakage
during replacement.
The TRIP and RESET values of the pressure switch depend upon the refrigerant gas used and are listed in the table below:
Axial fans
8 . 5 L e v e l s e n s o r
ATTENTION
- Take all the necessary precautionary measures to avoid accidental contact with powered elements.
- The voltage values inside the electric panel can be lethal for humans.
- The manufacturer is responsible for level sensor calibration and therefore further modifications are not necessary. Key (1) is sealed to
prevent tampering by the user.
The level sensor indicates the absence of process water inside the tank. An alarm, with relative blocking of the unit, appears on the control
display.
Level sensor calibration
(to be performed only on instruction by the MTA Service Centre) :
NOTE
If the electrical resistance of the liquid is outside the maximum range of the control device, green LED (3) will flash rapidly for 2 seconds while
amber LED (2) remains off, thus signalling a teach-in error.
ATTENTION
The level sensor has been calibrated by MTA to operate at maximum sensitivity admissible on the instrument (220kOhm).
Modifications to this setting may impair correct operation.
Pressure switch Refrigerant
TRIP RESET
bar PSI °C °F bar PSI °C °F
Axial fans
FP
R407C 18 261 46.4 115.5 14 203 37.0 98.6
1. Make sure the level probe is
immersed in the liquid (at least 1
cm).
2. Power on the system; green LED (3)
will illuminate steadily.
3. Amber LED (2) may illuminate or
remain off.
4. Press black “Teach” pushbutton (1)
and hold down for more than 2
seconds.
5. Green LED (3) will flash while
amber LED (2) can:
• illuminate, if it was previously
off
• remain illuminated, if it was
previously lit.
6. This sequence of steps causes the
device to self-calibrate in
accordance with the electrical
resistance of the liquid.
1
2
3