14
FAULT DESCRIPTION
INDICATIONS
POSSIBLE CAUSE OF FAULT
OPERATIONS TO BE PERFORMED
Water is not
heated
DHW LED ON
primary circuit shut-off valves closed
open the valves
modulating valve actuator connector disconnected
reconnect actuator connector
modulating valve actuator disconnected from valve body
reconnect actuator
modulating valve actuator faulty
call qualified personnel to have it
replaced
DHW temperature probe cable inverted with heating
probe
restore correct connection
presence of air in the system
vent the system
electronic controller not working
call qualified personnel to have it
replaced
valve obturator blocked in closed position
call qualified personnel to have it
replaced
centralised system not working/cold
contact person in charge of system
FAULT LED ON +
error code 6 active
DHW temperature probe disconnected
reconnect probe
DHW temperature probe faulty
call qualified personnel to have it
replaced
FAULT LED ON +
error code 79 active
incorrect switch setting
restore correct switch setting
FAULT LED ON +
error code 80 active
incorrect switch setting
restore correct switch setting
DHW LED OFF
DHW priority flow meter disconnected
reconnect flow meter
DHW priority flow meter faulty
call qualified personnel to have it
replaced
all LEDs are OFF
no electric power supply
restore HIU electric supply
protection fuse burnt out
call qualified personnel to have it
replaced
The water is hot
but does not
reach the
desired
temperature
DHW LED ON
domestic water cycle temperature set point too low
increase set point
primary circuit strainer of the HIU clogged
call qualified personnel to have it
serviced
heat exchanger partly clogged
call qualified personnel to have it
serviced
modulating valve actuator faulty
call qualified personnel to have it
replaced
valve obturator blocked in intermediate position
call qualified personnel to have it
replaced
modulating valve actuator connector disconnected
reconnect actuator connector
DHW temperature probe cable inverted with heating
probe
restore correct connection
excessive demand for DHW
decrease demand
electronic controller not working
call qualified personnel to have it
replaced
centralised system temperature insufficient
contact person in charge of system
primary circuit flow rate insufficient
contact person in charge of system
Hot water
temperature is
too high
DHW LED ON
domestic water cycle temperature set point too high
decrease set point
DHW temperature probe cable inverted with heating
probe
restore correct connection
modulating valve actuator faulty
call qualified personnel to have it
replaced
valve obturator blocked in intermediate or open position
call qualified personnel to have it
replaced
electronic controller not working
call qualified personnel to have it
replaced
primary circuit excessive pressure
contact person in charge of system
Hot water flow
rate is
insufficient
DHW LED ON
HIU strainer clogged
call qualified personnel to have it
serviced
possible domestic water system shut-off valves
partially closed
open the valves
centralised domestic circuit cold water flow rate
insufficient
call qualified personnel to have it
serviced
Hot water flow
rate is zero
DHW LED OFF
possible domestic water system shut-off valves closed
open the valves
no cold water in centralised domestic circuit
call qualified personnel to have it
serviced
HIU strainer completely clogged
call qualified personnel to have it
serviced
heat exchanger completely blocked
call qualified personnel to have it
serviced
Troubleshooting
