Wolf COB Technical Manual And Installation Instructions page 37

Cylinder hysteresis
Parameters HG15
HG15
5
Factory setting: 5 K
Setting range: 1 to 30 K
Run-on time, cylinder
charging pump
Parameter HG 19
HG19
5
Factory setting: 5 min
Setting range: 0 to 10 min
max. cylinder heating time
Parameter HG20
HG20
2
Factory setting: 2 hrs
Setting range: 0 to 5 hrs
Minimum boiler water
temperature
TK-min.
Parameters HG21
HG21
20
Factory setting: 20 °C
Setting range: 20 to 90°C
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23 Contractor level parameters
The cylinder hysteresis regulates the start point for cylinder heating. The higher the
setting, the lower the start point for cylinder heating.
Example: Set cylinder temperature 60 °C
Cylinder hysteresis 5 K
Cylinder heating commences at 55 °C and ends at 60 °C.
After completing cylinder heating in summer mode (the cylinder has reached the set
temperature), the cylinder loading pump will run on up to the max. set run-on time.
The cylinder primary pump will switch OFF prematurely if, during the run-on time, the
boiler water temperature cools down to a differential between boiler and cylinder water
temperature of 5 K, to prevent the boiler cooling down too severely.
In winter mode, the cylinder loading pump runs on for a fixed time of 2 minutes after
successful cylinder heating (independently of parameter HG19).
Cylinder heating commences as soon as the cylinder temperature sensor calls for heat.
The heating circuit pumps would be constantly switched off if the boiler was undersized,
the cylinder was scaled up or if DHW was constantly drawn off during DHW priority mode.
The accommodation would then cool down significantly. To limit this effect, it is possible
to specify a max. cylinder heating time. If the set maximum cylinder heating time has
expired, error message FC52 appears on the BM module. The control unit reverts to
heating mode and cycles in the selected rhythm (HG20) between heating and cylinder
heating mode, regardless of whether the cylinder has reached its set temperature or
not. This function remains enabled even in parallel mode (parameter A10 set to 1). It
is only disabled if it is set to 0.
Set this parameter to 0 in heating systems with a high DHW consumption, e.g. hotels,
sports facilities etc.
The control unit is equipped with an electronic boiler temperature controller which has an
adjustable min. start temperature. The burner is switched on subject to the cycle block
if this temperature is not achieved when heat is demanded. If there is no heat demand,
the minimum boiler water temperature TK-min may also be undershot.
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