51
7
7.4 DHW function (only version -C)
On version -C a plate heat exchanger is integrated into the
WTC for domestic hot water operation. The throughput
quantity is determined and used for the control. The outlet
temperature is controlled and monitored by a temperature
sensor. A flow sensor recognised the start of demand
(quantity > 2.3
l
/
min
) and the end of demand.
The following functions are integrated to improve domestic
hot water operation:
•
Keep warm function (comfort function):
During the normal DHW operating phase, the plate
heat exchanger is heated up to an adjustable
temperature and held at that temperature. This means
hot water is available immediately.
If using the digital clock WCM-DU with connection to
plug 4 (H2), this keep warm function can be switched
off at night.
•
Boost function:
During the boost function, the burner rating is
increased by approx. 15% depending on the DHW
outlet temperature set (
≥
50° C) and the current water
quantity used (> 4
l
/
min
) to increase the amount of hot
water available.
Once water has been drawn off or the comfort function
has ended, the 3 way valve in winter operation remains in
the DHW position for a further 3 minutes. In summer
operation it remains in the DHW position permanantly.
The DHW quantity in the unit is limited to approx.
7.5 l/min (± 10 %). This avoids a temperature drop if
more water is drawn off.
Burner off T
DHW
> T
DHWset
+ 5 K
Burner on T
DHW
< T
DHWset
Parameter setting:
❑
DHW temperature in end user level, symbol
❑
P38 - max. rating in DHW operation
(100% recommended)
❑
P60 - Comfort function (keep warm temperature)
Switch off of comfort function when P60 = “---”
❑
P61 - Hysteresis comfort operation
❑
P62 - 1 Booster activated
0 Booster deactivated
A heat up procedure is initiated in setback operation, if
the DHW minus the subtraction value is not
maintained.
This requires either the digital clock WCM-DU
(connection of second channel to plug 4 [H2]) or the
remote control WCM-FB, both available as accessories.
Setting both temperatures:
•
Normal temperature in end user level, symbol
•
Setback temperature in heating engineer level:
normal temperature - P53
Parameter settings
:
❑
Normal temperature, end user level symbol
❑
P50 Flow. temperature overload (recommended 20 K)
❑
P51 Switch differential DHW
❑
P52 max. DHW operating time
❑
P53 Setback temperature
(only when using WCM-DU)
7.3 DHW function (only version -W)
In this version, the WTC is equipped with a 3 way valve.
The DHW control is carried out by a 2 point controller with
adjustable hysteresis.
The domestic hot water operation has priority over the
heating operation.
DHW operation is carried out when the temperature in the
water heater is T
DHW
< T
DHW
set - P51 (P51
➩
heating
engineer level).
Modulation is carried out to the flow temperature of the
WTC, which is increased by temperature increase P50.
DHW operation is switched off, when the DHW sensor
has reached the setpoint T
DHW
. Following this the pump
continues to run for 3 minutes, the 3 way valve is set for
DHW operation. DHW operation can also be limited in
time (P52
➩
heating engineer level). It is possible to set a
setback level for the DHW temperature using a subtraction
value (P53
➩
heating engineer level).
7.5 Warm water operation (version -H / -H-0)
The WTC can control an external DHW circuit. To do
this, the DHW sensor B3 must be connected.
The WCM-CPU recognises this modification and
indicates the configuration in parameter P10 with a W.
A change-over valve or a separate DHW pump can be
driven via outputs VA and MFA (electrical connection see
Ch. 4.6.2 and Ch. 4.6.3).
The function is identical to the DHW function of
version -W.
Summary of Contents for thermo condens WTC 15-A
Page 92: ...92 Notes A ...
Page 93: ...93 A ...
