Technical data

32
8. MAINTENANCE
8.1 FUSE REPLACEMENT
The AST Controller has a internal fuse located under the front cover - see
fig. 8.1A.
If the display or Indicator lamp do not light up when power to the controller
is switched On it indicates a possible fuse or power failure.
A spare fuse is supplied with the controller.
Fuse type SMTX T4/250V.
8.2 SENSOR FAILURE
COL
888.8
Error Code
Symptoms of a sensor failure are:-
Indicator lamp flashes red, displayed and an error code displayed
in place of the sensor temperature.
There are two error codes:-
888.8 indicates a line break to cable or sensor.
-88.8 indicates short circuit of cable or sensor.
Pt1000 temperature sensors can be checked with a multi meter.
The chart below gives resistance values Ω corresponding to temperatures
C°01-5-05015102520353045405
Ω
16908900019101930185018701790171116311551157114911
C°550656075708580959001501011511
Ω
3121232125211721092190318231743166315831404132412441
8.4 FAULT FINDING
The following two pages have fault finding procedures.
If the display or indicator lamp do not light up when power to the
controller is switched On it indicates a possible fuse or power failure
- see 8.1.
If the system is not operating as expected, it is recommended that the first
course of action is to set all values to the default values OR the values
recorded by the commissioning engineer; these are shown in section 7.
8.3 CONTROLLER FAILURE
If the controller fails to start (operating lamp On and display lit) then check
wiring, fuses and power supply. If these are all OK then the controller is
faulty.
The operation of the controllers Relays R1 and R2 can be checked using
manual switching (HND, HND1 and HND 2) see section 7.
IMPORTANT
No attempt should be made to repair the controller - consult Ariston.
FIG. 8.1A FUSE LOCATION