Diagnostics - Troubleshooting; General; Displaying Alarms; Resetting Alarms - Danfoss BW10 020-090 Operation Instructions Manual

5.11.2 – Controls
The heating module controls the following elements:
• A three-way valve to switch over to domestic hot water
production
• An additional water pump in the heating circuit
• Up to four electric heating stages (for supplementary
safety stage heating)
5.11.3 – User connection terminals
Three volt-free contacts are available at a user connection
terminal board:
• A contact for DHW demand from the tank
• A volt-free contact for DHW priority
• A volt-free contact for the summer mode
5.11.4 – Control of additional electric heater stages
The heat pump units can control up to four electric heater
stages as supplementary heating.
Electric heater stages are activated to supplement the heating
capacity if the following conditions are satisfied:
• The unit uses 100% of its available heating capacity or the
unit is limited in its operation by a protection mode (e.g.
low suction temperature protection) and in all cases cannot
satisfy the heating demand.
• The outside temperature is below a configurable threshold
(see HCCONFIG menu)
• Unit demand limitation is not active.
If required the user can configure the last electric heater stage
available as a safety stage. That safety stage is only activated in
addition to the other stages, if there is a unit fault that prevents
the use of the heating capacity. The other electric heater stages
continue to operate a described above.
The electric heater stages only operate in the heating mode, but
not during domestc hot water production.
5.11.5 – Heating or domestic hot water
A three-way valve permits switching the heating capacity to a
heating circuit (fan coil units, radiators or floor heating), or to a
domestic hot water tank.
The unit requests changeover to the domestic hot water mode if
all the following conditions have been met:
• The volt-free tank request contact is closed AND
• Time schedule 3 is in an occupied period OR the volt-free
priority contact is closed.
Based on the operating mode the water setpoint is adjusted:
• In heating mode, setpoints hsp1 and hsp2 are used. They
can be modified by user reset or based on the outside
temperature.
• In domestic hot water production mode setpoint hsp3 is
used. No setpoint reset is used.
The unit requests changeover to the heating mode, if at least
one of the following conditions applies:
• The volt-free tank request contact is open OR
• The maximum operating duration in the DHW mode has
finished OR
• Time schedule 3 is in an unoccupied period.
20
If a mode change is requested while a compressor is operat-ing,
it is stopped before the three-way valve changes to the new
mode, and then the unit is re-started.
If the unit is in domestic hot water production mode, a "DHW"
message is displayed on the user interface next to the current
operating mode. Example: "Local Running DHW".
5.11.6 – Summer mode
The summer mode is activated when the outside temperature
exceeds the parameter threshold summ_oat during the summ_
on time. It is deactivated if the outside temperature returns to a
lower value than the parameter threshold summ_oat during the
summ_off time. The summer mode can also be activated if the
volt-free contact SUMM_SW is closed.
5.11.7 – Additonal water pump
An additional water pump, installed in the heating water circuit
starts if the summer mode is deactivated. If the anti-stick
function is configured, the additional water pump starts
periodically.

6 - DIAGNOSTICS - TROUBLESHOOTING

6.1 - General

The control system has many fault tracing aid functions. The
local interface and its various menus give access to all unit
operating conditions. If an operating fault is detected, an alarm
is activated and an alarm code is stored in the Alarms menu,
sub-menus CUR_ALRM and ALARMRST.

6.2 - Displaying alarms

The alarm LED on the interface (see chapter 4.1) allows the
quick display of the unit status.
• A flashing LED shows that the circuit is operating but
there is an alert.
• A steady LED shows that the circuit has been shut down
due to a fault.
The ALARMRST menu on the main interface displays up to
five fault codes that are active on the unit.

6.3 - Resetting alarms

When the cause of the alarm has been corrected the alarm can
be reset, depending on the type, either automatically on return
to normal, or manually when action has been taken on the unit.
Alarms can be reset even if the unit is running.
This means that an alarm can be reset without stopping the
machine. In the event of a power supply interrupt, the unit
restarts automatically without the need for an external
command. However, any faults active when the supply is
interrupted are saved and may in certain cases prevent a circuit
or a unit from restarting.
A manual reset must be run from the main interface via the
ALARMRST menu, item RST_ALM. Depending on the
configuration in the GENCONF menu, access to the item may
be protected by a password.