Viessmann VITOTRONIC 200 Service Instructions Manual page 126

Diagnosis
System
(cont.)
Event
E
"Compressor stop"
"Integral value reached"
"Integral value undershot"
"Alternative heating"
"Pump run-on"
"High demand"
"Demand externally"
"Block externally"
"Natural defrosting"
"Output at zero"
"EEV shutdown"
"Refrigerant circuit fault"
"Frost protection"
"Safety chain"
"Primary temperature outside
application limits"
"Timer expired"
"Max. value exceeded"
"Output demand"
"Max. temperature in secon-
dary circuit exceeded"
"Flow switch"
"Defrost"
"Mains protection"
"Limit pressure"
"Temperature rise"
"Contact humidistat"
"Min. temperature in secon-
dary circuit undershot"
State machines "SM"
F
State machines indicate the status of control circuits in
the heat pump control unit. This enables the functions
of individual heat pump and heating system compo-
nents to be traced.
126
Causes
Compressor has stopped. There is no longer a demand.
■
or
A fault has occurred.
■
Integral for starting a component, a function or an operating stage has excee-
ded the start threshold.
Integral for starting a component, a function or an operating stage has under-
shot the start threshold.
Should the compressor be unable to start, an external heat generator, instan-
taneous heating water heater or immersion heater will be started.
Run-on time of a circulation pump active, e.g. secondary pump after the com-
pressor has shut down
Demand "High" or "Maximum" for control circuit is active.
"Demand externally" function is active.
"Block externally" function is active.
Defrosting with ambient air: Refrigerant circuit is not operational.
No more demand for the heat source.
Operating point outside application limits or refrigerant circuit controller fault
(see "Diagnosis" "Refrigerant circuit"
Temperature at the condenser too low on several occasions; observe mes-
sage "AC Compressor shutdown".
Temperature at the condenser too low
■
Temperature inside the DHW cylinder too low
■
Safety chain interrupted
Flow temperature primary circuit or air intake temperature outside the control
limits; observe "CB Flow temp. primary" message.
Active timer has expired, e.g. "Start-up time heat pump": See chapter "Tim-
er".
Max. hot gas temperature or max. high pressure condenser exceeded.
Production manager issued demand to heat source, e.g. heat pump, external
heat generator, etc.
Max. flow temperature in secondary circuit has been exceeded
Flow switch has responded.
■
or
No jumper installed.
■
/ : Defrosting by refrigerant circuit reversal
Instantaneous heating water heater is stopped immediately before the com-
pressor starts.
Min. suction gas pressure undershot.
Max. temperature differential between evaporator and condenser exceeded or
min. temperature differential between evaporator and condenser undershot.
Contact humidistat has responded.
Min. secondary circuit flow temperature undershot
"Message history")