Viessmann VITOCAL 242-S Installation And Service Instructions Manual page 96

Troubleshooting
Repairs
(cont.)
Draining secondary side heat pump
1. Close the on-site boiler drain & fill
valve.
Checking the sensors
Sensor
■ Outside temperature sensor (F0)
■ Buffer temperature sensor (F4)
■ Cylinder temperature sensor (F6)
■ Flow temperature sensor, system
(F13)
■ Flow temperature sensor, cooling
circuit (direct heating circuit A1/
HC1 or separate cooling circuit
SKK) (F14)
■ Return temperature sensor, solar
circuit (F23)
■ Room temperature sensors
■ Flow temperature sensor, secon-
dary circuit (F8)
■ Return temperature sensor, sec-
ondary circuit (F9)
■ Flow temperature sensor, secon-
dary circuit upstream of instanta-
neous heating water heater
(LWT)
■ Liquid gas temperature sensor
(IRT)
■ Temperature sensor, refrigerant
inlet, evaporator (OCT)
■ Temperature sensor, evaporator
(OMT)
■ Temperature sensor, air intake,
evaporator (OAT)
96
2. Drain the heat pump at the secondary
circuit fill & drain valve (see chapter
"Overview of internal components:
Internal unit").
Test el- Installed loca-
ement tion
NTC Internal unit (see
10 kΩ page 90)
Pt500A Internal unit (see
(PTC) page 90)
NTC Internal unit (see
10 kΩ page 90)
NTC External unit
10 kΩ (see page 92)
Connection
Controller and
sensor PCB (see
page 42)
Controller and
sensor PCB (see
page 42)
AVI PCB (see
service instruc-
tions
Vitotronic 200,
type WO1C)
Refrigerant circuit
controller (ob-
serve label on the
external unit)