Flow Sensor Primary - Viessmann VITOTRONIC 200 Service Instructions Manual

Message overview
(cont.)

30 Flow sensor primary

Operation with temperature value of return tempera-
■
ture sensor in primary circuit, plus 3 K.
■ If the primary circuit flow and return temperature sen-
sors are both faulty at the same time, the message
"A9 Heat pump" appears and the heat pump shuts
down.
Cause
Short circuit, primary circuit flow temperature sensor
(heat pump air intake or brine inlet)
31 Return sensor primary
■ Operation with temperature value of flow tempera-
ture sensor in primary circuit, minus 2 K.
■ If the primary circuit flow and return temperature sen-
sors are both faulty at the same time, the message
"A9 Heat pump" appears and the heat pump shuts
down.
Cause
Short circuit, primary circuit return temperature sensor
(heat pump air discharge or brine outlet)
32 Evaporator temp.sensr
No central heating or central cooling; only defrosting
■
The air discharge temperature sensor is used for
■
defrosting the evaporator.
Cause
Short circuit, evaporator air intake temperature sensor
36 Hot gas temp sensor 1
Compressor 1 in a 2-stage refrigerant circuit is switched OFF.
Cause
The stop limit for the hot gas temperature at compres-
sor 1 is exceeded.
Measure
Check resistance value (Pt500A) at terminals X25.1/
X25.2: See "Controller and sensor PCB".
Measure
Check resistance value (Pt500A) at terminals X25.3/
X25.4: See "Controller and sensor PCB".
Measure
Vitocal 200-A, type AWCI-AC 201.A:
■
Check resistance value Pt500A at the connection on
the EEV PCB: See "EEV PCB [2]".
Vitocal 100-S/111-S
■
Check resistance value NTC 15 k
on the main PCB of the outdoor unit: See "Main PCB
[7] / [7-1]".
Action
Check the compressor oil level. Top up with oil if re-
■
quired.
Check if there is excess oil in the oil separator. Have
■
the refrigerant circuit checked by a refrigeration engi-
neer if necessary.
Troubleshooting
at the connection
Ω
81