Troubleshooting - Danfoss Termix VVX-I-R FI - 7 Series Operating Manual

Termix VVX-I-R FI - 7 Series DS fully insulated

Troubleshooting

Area of operation
Instantaneous water heater,
thermostatic
Indirect heating, thermostatic
LGB40450
Problem
The strainer in the supply
or return line is clogged up
Too high DHW flow rate
Defective mixer tap
Defective or blocked check
valve on the circulation valve
Incorrect DHW
Incorrect set-point on the
temperature
DHW controller
Defective DHW controller
Plate heat exchanger has calcified Replace the heat exchanger
The filter on the cold water supply
Domestic hot water
is clogged up
flow is too low
Plate heat exchanger has calcified Replace the heat exchanger
Idle temperature is too low
Long wait for
domestic hot water
DHW circulation temperature
has been set too low
The strainer in the supply
or return line is clogged up
Incorrect set-point on the
temperature controller
Defective temperature controller
Incorrectly set differential
pressure regulator
Defective differential pressure
Incorrect flow
regulator
temperature for
Air bubbles in the system
space heating
Incorrect system pressure
The pump is not working
Air in the pump
The pump is blocked
The pump has been set at too
low a level
Uneven heat distribution in the
building due to incorrectly set
balancing valves on heat emitters
Blocked heat exchanger
Space heating flow temperature
is too high
Defective temperature controller
Primary return
temperature
Incorrect setting or dimensioning
too high
of the building's heat emitters
Pump pressure is too high
Defective non-return valve
Blocked heat exchanger
Incorrectly set differential
pressure regulator
Defective differential
Noise in the unit
pressure regulator
Pump pressure is too high
Possible cause
Clean the strainer
Check the dimensioning of DHW load, actual flow
temperature and differential pressure
Check if the mixer tap is defective and if so, replace
Check and replace if defective
Set the DHW controller's thermostat to the correct value
according to the section "Adjustments, domestic hot water"
1) Check the sensor: Remove the sensor head from
the valve. If the DHW temperature then increases,
replace the sensor
2) If the DHW temperature does not increase,
replace the entire valve
Clean the filter
Set the DHW controller's thermostat to the correct value
according to the section "Adjustments, domestic hot water"
Set the thermostat higher or turn up the DHW circulation
pump
Clean the strainer
Set the thermostat of the temperature controller to
the correct value according to the section "Temperature
control of heating unit"
1) Check the controller: Remove the thermostat
from the valve. If the temperature then increases,
replace the thermostat
2) Alternatively, check and exercise the valve.
Replace the valve if defective
Set the differential pressure regulator to the correct value
according to the section "Differential pressure regulator"
Check and replace if defective
Bleed the installation thoroughly
Check the system pressure on a pressure gauge
and top up with water if necessary
Check whether there is power to the pump
Make sure there is no air in the pump housing
Exercise the pump using the centre screw
Set the pump correctly, see the section
"Circulation pump UPM3"
Adjust or install balancing valves
Flush the system and check that a strainer has been fitted
on the secondary side. Then replace the heat exchanger
Set the thermostat of the temperature controller to the
correct value according to the section "Temperature control
of heating unit"
1) Check the controller: Remove the thermostat
from the valve. If the temperature then increases,
replace the thermostat
2) Alternatively, check and exercise the valve.
Replace the valve if defective
Check, set, replace
Set the pump to a lower setting, see the section
"Circulation pump UPM3"
Check and replace if defective
Flush the system and check that a strainer has been fitted
on the secondary side. Then replace the heat exchanger
Set the differential pressure regulator to the correct value
according to the section "Differential pressure regulator"
Check and replace if defective
Set the pump to a lower setting, see the section
"Circulation pump UPM3"
Solution
© Danfoss | 2021.06| 29