7 - STANDARD CONTROL OPERATIONS AND OPTIONS
7.6 Built-in DHW and space heating control
AQUACIAT
CALEO
units are specially designed to optimise the
operation of heating installations that require hot-water production
for traditional heating (SHC) and domestic hot water (DHW)
requirements.
Connect Touch permits constant and automatic optimisation
of the unit:
• Control of a three-way directional on/off valve based on
the heating or domestic hot water requirements (3-way
valve used to switch between Space Heating Control and
Domestic Hot Water). By default, the unit is operating in
Space Heating mode.
• Control of the electric heater stages can complement the
heating loop (1 to 4 electric heating stages).
7.6.1 Heating or domestic hot water mode
The 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. 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.
The unit requests changeover to DHW mode provided that
both water tank conditions and unit conditions are met:
• Water tank conditions:
• “DHW Request Input” volt-free contact is closed or
“DHW Tank Temperature” is below “DHW Setpoint”
AND
• The third timer program (schedule 3) is set to occupied
(DHW mode requested) and the anti-legionella
program is not requested (see section
).
• Unit conditions:
•
Summer mode is active (space heating is not required)
OR
•
Summer mode is NOT active and the minimum SHC
operating time and the maximum DHW operating time
parameters allow for that (service-configured parameters).
NOTE: Domestic Hot Water schedule can be activated
regardless of the current operating mode (Local/Remote/Net).
Based on the operating mode (SHC or DHW) the water setpoint
is adjusted:
• In heating mode, hsp1 and hsp2 are used. They can be
modified by user reset (see section 7.5.2
).
• In domestic hot water production mode, DHW setpoint 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.
•
The maximum operating time for the DHW mode has
elapsed.
• Time schedule 3 is in an unoccupied period
(DHW mode not requested).
If a mode change is requested while a compressor is operating,
it is stopped before the three-way valve changes to the new
mode, and then the unit is re-started.
7.6.2 Anti-legionella
Water storage tanks where the water may stagnate for some
time could create the environment allowing for the growth of
legionella bacteria. To prevent the risk of legionella growth in the
hot water tank, the control performs the anti-legionella treatment
which means that water temperature is increased until it reaches
the Anti-Legionella setpoint (legionella bacteria do not survive in
temperature at 60°C).
The anti-legionella program can be activated automatically via
the schedule setting. To activate the anti-legionella program,
the installer should set the fourth timer program (schedule 4).
The water tank temperature is increased until the anti-legionella
setpoint [leg_sp] is reached or a 6-hour period has elapsed.
The program cannot be activated more than once within
6 hours. For more information about setting the anti-legionella
schedule, see section
7.6.3 Summer mode
The Summer mode is used to control Domestic Hot Water mode.
When the Summer mode is active, space heating is not required,
and the unit can increase the water temperature in the water tank
in order to provide hot domestic water.
The Summer mode can be activated only when the outdoor air
temperature exceeds the predefined Summer OAT threshold
(“Maximum OAT Threshold”).
To set Summer OAT threshold
1. Navigate to the Configuration menu.
2. Select
Heat/Cool Configuration
(HCCONFIG).
3. Set
Maximum OAT Threshold
[max_th].
Maximum OAT Threshold [max_th]
5 to 100°C
100°C
The Summer mode will end when the outdoor air temperature
drops below the predefined Summer OAT threshold - 2K,
e.g. if the Summer OAT threshold is set to 20°C, the Summer
mode will end as soon as the outdoor air temperature reaches
the temperature of 18°C.
NOTE: When the Maximum OAT Threshold parameter is
set to an unreachable value, e.g. 100°C, then the Summer
mode will be disabled.
EN - 23 AQUACIAT
CALEO
