9. Fault finding the product
This is a complete list of alarm and warning codes for the MIXIT
fieldbus connection. For more information about fault finding of
MIXIT and MAGNA3, see the installation and operating instructions
for the products
9.1 The external control icon is not switched on
Cause
The configuration may have failed.
Remedy
•
Check the BACnet interface configuration via Grundfos GO
Remote.
When a fieldbus connection is established and data is
transferred, the external control icon on the MIXIT operating
panel will light up. The light will switch off 30 minutes after
data communication via the fieldbus has stopped.
Cause
The connections at the terminal board are incorrect.
Remedy
•
Try switching wires at A2 and B2 terminals.
When a fieldbus connection is established and data is
transferred, the external control icon on the MIXIT operating
panel will light up. The light will switch off 30 minutes after
data communication via the fieldbus has stopped.
9.2 Data is read from the MIXIT unit but it is not reacting
on a setpoint change
Cause
The product is in local control instead of bus control.
Remedy
•
Check that MIXIT is in bus control.
The actual state is read at BI,0. The status is changed
via BO,0. Note that local control is the default setting.
•
Check that MV,0 is configured correctly.
- MV,0 = 3: temp_setpoint_remote
- MV,0 = 5: outdoor_temp_remote
9.3 The controlled temperature is much different than
the requested temperature for more than 10-20
minutes
Cause
The setpoint source is not configured correctly.
Remedy
1.
If the controlled temperature at AI,22 is much different than
the setpoint at AI,0, after several minutes, check if the
setpoint in AI,0 is the same as requested in AO,0.
2.
Check that MV,0 is configured for remote setpoint.
Cause
The limit functions may be enabled which reduces the setpoint.
Remedy
1.
Check that the actual setpoint in AI,2 is the same as the
registered remote setpoint in AI,0.
2.
Check if one or more limit functions are active.
Check if BV,0, BV,1, BV,2 and BV,3 are set to 1.
If one or more limit functions are active and the MIXIT unit is
running at or above the threshold associated with the active
limit function (XX to XX), the remote setpoint in AI,0 is
reduced until the threshold is reached.
3.
If no limit functions are active and the response is too slow,
run the auto-tuning function from Grundfos GO Remote:
Settings
>
Temperature controller
>
Automatic tune
.
Cause
The gain of the closed-loop controller is too low.
Remedy
1.
Increase the proportional gain with Grundfos GO Remote
with 10 % of the actual gain at a time until the response is
satisfactory. Wait for several minutes between each increase.
2.
If necessary, adjust the integral time with Grundfos GO
Remote.
9.4 The MIXIT unit was put into bus control, but it is now
in local control again
Cause
The MIXIT unit starts in local control. The actual status is not kept
during a power cycle.
Remedy
•
Check the status in BI,0.
•
If it is set to 0, set BO,0 to 1 again.
9.5 The MIXIT unit was stopped from BACnet command,
but it has started again
Cause
The MIXIT unit is starting again. The actual start/stop status is not
kept during a power cycle.
Remedy
•
Check the status in BI,2.
•
If it is set to 1, set BO,0 to 1 and then set BO,1 to 0.
9.6 The MIXIT unit does not start the pump when a start
signal is given in BO,1
Cause
The pump state is incorrect.
Remedy
•
Ensure the requested pump run state in BI,2 is set to 1 in
order to start the pump.
•
Check if the pump is stopped locally via the pump interface.
At the MAGNA3 pump, local stop has priority over bus
control.
9.7 The MIXIT unit does not stop the pump when a stop
signal is given in BO,1
Cause
The pump state is incorrect.
Remedy
•
Ensure the requested pump run state in BI,2 is set to 0 in
order to stop the pump.
•
Check if the pump is running at maximum speed.
At the MAGNA3 pump, local stop has priority over bus
control.
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English (GB)
