11
Before opening DRHX
, the mains voltage must be
disconnected for at least 3 minutes
to ensure that there is no
risk of dangerous residual currents in electronic circuits or capacitors. If DRHX has no operating signal, but natural
drafts through the air handling unit cause the rotor and thus the stepper motor to rotate, there is a risk that the
stepper motor will induce voltage on the DRHX stepper motor terminals, making them dangerous to touch.
When servicing or troubleshooting the stepper motor: The stepper motor can become very hot >60°C.
Trouble shooting alarm codes
-
also see page 10 and 12
Table 19.1
Alarm
Reason to alarm
Solution
E01
Belt is slipping (around the pulley) or broken
Tension/ replace the belt.
External rotation guard has been activated even though it
is not use (is a jumper placed between Digital input 2 +
GND, ground?). No rotation guard is wired to the DRHX.
Deactivate external rotor guard by
removing the jumper.
If external rotation guard is used: check if magnet/ sensor/
holder is loose or missing. Check so that sensor is in front
of the magnet and with correct distance (see page 9).
Fix magnet/ sensor/ holder to its position
Distance between sensor and magnet
should be 3-5 mm (see page 9)
Accidental calibration of the rotor and pulley by "double"
clicked when running the test function (page 7) or
forgetting to take the belt off before calibration test (page
10).
Make the test/ calibration again, see page
10.
If the motor is too powerful for the rotors load (large motor
to a very small load). The rotor torque is lower than the
internal rotor guards minimal torque limit for chosen type of
DRHX/ MRHX system (i.e spare part for old RHE).
Exchange type of MRHX motor and if
needed DRHX controller so its fits the
rotor type.
Contact Hoval for support.
E06
Wobbling belt. Could be caused by incorrect mounting,
damaged or out of shape rotor.
Correct and tension the belt.
Check installation for damage.
If needed, contact Hoval for support.
If springs or dampers are used with the motor bracket, the
vibrations can stop the MRHX motor, internal sensor will
be giving error (e.g. if use new spare part to old RHE).
Change to a fixed motor bracket (without
spring, dampers).
If the motor is under dimensioned (small motor to a large
rotor load), the motor will not be able to turn the rotor (i.e
new spare part for an old RHE)
Check if the correct size/ type of drive
equipment is mounted.
If correct
,
maintenance is needed, i.e adjust the
brush sealing (see manual for RHE).
If wrong
drive equipment: exchange to
correct type/ size.
Check the pressure drop, air volumes (also difference
between the channels) and velocity.
See maximum values in Hoval handbook.
E09
Internal error between MOC (motor) and AOC (application):
Can be an update issue when installing new software
Try to re-install firmware again.
Contact Hoval for support.
If the error occurs by after the system has been running for
a period of time
Exchange the controller DRHX.
Contact Hoval for support.
