Viessmann VITOCAL 250-A - Page 101

101
Measures
1. Check the sensor and connection:
Wall mounted indoor unit:
Connection on underside of the appliance, 6-pole
connection socket on the right, terminals 9 and 10
(plug 5 on HPMU electronics module)
Floorstanding indoor unit:
Connection X3.3/X3.4 (plug 5) on HPMU electronics
module
■
Check wires and plugs for correct seating.
■
Check connections for contact corrosion.
■
Check cables for mechanical damage, e.g. crush-
ing, kinking, chafing or breakage.
2. Check resistor R for NTC 10 kΩ on the disconnected
plug. If R < 500 Ω, replace the sensor.
3. Replace HPMU electronics module.
F.13 Lead break, outside temperature sensor
F.13
System characteristics
An outside temperature value of 0 °C is used to calcu-
late the set flow temperature.
Cause
Lead break, outside temperature sensor
Measures
1. Check connection 1 to the HPMU electronics mod-
ule:
Wall mounted indoor unit:
Connection on the underside of the appliance, 6-
pole connection socket on the right, terminals 11
and 12
Floorstanding indoor unit:
Connection on the upper PCB, luster terminals for
sensors, terminals 1.5/1.6
■
Check wires and plugs for correct seating.
■
Check connections for contact corrosion.
■
Check cables for mechanical damage, e.g. crush-
ing, kinking, chafing or breakage.
2. Check resistor R for NTC 10 kΩ on the disconnected
plug. If R > 300 kΩ, replace the sensor.
3. Replace HPMU electronics module.
F.14 Short circuit, outside temperature sensor
F.14
System characteristics
An outside temperature value of 0 °C is used to calcu-
late the set flow temperature.
Cause
Short circuit, outside temperature sensor
Measures
1. Check the sensor and connection 1 on the HPMU
electronics module:
Wall mounted indoor unit:
Connection on the underside of the appliance, 6-
pole connection socket on the right, terminals 11
and 12
Floorstanding indoor unit:
Connection on the upper PCB, luster terminals for
sensors, terminals 1.5/1.6
■
Check wires and plugs for correct seating.
■
Check connections for contact corrosion.
■
Check cables for mechanical damage, e.g. crush-
ing, kinking, chafing or breakage.
2. Check resistor R for NTC 10 kΩ on the disconnected
plug. If R < 500 Ω, replace the sensor.
3. Replace HPMU electronics module.
Messages
Fault messages (cont.)
6218234
Diagnosis