First start-up
Installation, use and maintenance manual – K18 Hybrigas
43
5
GHP probe to AUX PROBE 1 clamp (see Paragraph 4.7
and set parameter 210 to 1 (probe for space heating regula-
tion).
▶
If weather compensation is activated (see Paragraph
6.5.1
p. 47), the installation of an outdoor temperature
probe EXT.T (Optional OSND007) is recommended; install
this probe in North facing, protected by direct sunlight and
far from heat sources (windows, discharges, ecc.) and con-
nect it to clamp AUX PROBE 2 (see Paragraph 4.7
set parameter 209 to 2 (outdoor temperature probe). If this
probe is not installed weather compensation will be based
on the value provided by outdoor temperature probe on
board unit, significantly less accurate.
5.5.5
Auxiliary boiler (boiler module) management
settings
▶
Make sure that parameters 49, 52, 53, 54 and 55 are set to
their default value as shown in Table 5.3
▶
With reference to the possible functions of the auxiliary
boiler (condensing boiler module) for the space heating ser-
vice (see Paragraph 1.1.4
p. 8 and further on in this Para-
graph), set parameter 50 to:
1. for emergency mode;
2. for integration mode;
3. (default value) for integration and replacement mode.
▶
In the presence of the DHW service (only with the OQLT019
system controller), with reference to the possible functions
of the auxiliary boiler for this service (see also further on in
this Paragraph), set parameter 51 to:
0. to exclude the auxiliary boiler from operating on
the DHW service (DHW produced exclusively with
the K18 unit);
1. for the emergency mode (activation of the auxilia-
ry boiler only in case of an alarm on K18 unit);
2. for the integration mode (activation of the aux-
iliary boiler in addition to the K18 unit, when
necessary);
3. for replacement mode (DHW produced only with
auxiliary boiler);
4. (default value) for the integration and replace-
ment mode (activation of the auxiliary boiler in ad-
dition and, in certain conditions, in replacement of
the K18 unit).
▶
The setpoint value communicated by 0-10 V signal to the
auxiliary boiler can be increased by a constant boost value
with respect to the actual system setpoint. This is sometimes
useful to guarantee that the outlet manifold can actually
reach the setpoint, even despite water mixing occurring on
the secondary circuit. If required, set parameter 203 to the
desired boost value. It is recommended to limit the boost
value to that which is strictly needed.
▶
It is possible to inhibit auxiliary boiler operation in integra-
tion mode for space heating service (not for DHW service)
above a set outdoor temperature threshold.
To use this function, set parameter 185 to the desired
outdoor temperature threshold value.
To disable this function, set parameter 185 to maximum
value (40 °C).
Even when inhibited by the above function, the auxiliary
boiler remains active for the emergency function.
The function uses the filtered value with a constant time
of 30' with respect to the instantaneous value as the
outdoor temperature.
Integration and replacement mode on space heating service
If the control mode of the boiler module is integration and re-
placement (parameter 50 set to 3 by default), the system uses
certain replacement criteria of the heat pump module for the
space heating service, using only the boiler module. The re-
placement criteria can be modified or inhibited by using certain
parameters.
1. Replacement at low outdoor temperature: the heat pump
module of the unit is replaced with the boiler module if the
outdoor temperature drops below a given value. This crite-
rion is particularly useful when the system requires a par-
ticularly high delivery temperature (which exceeds also the
operating limits of the heat pump) when the outdoor tem-
perature is very low.
To use this feature, set the threshold value of the outdoor
temperature in parameter 217.
To deactivate the replacement function, set parameter
217 to the minimum value allowed (-30 °C, default val-
ue).
2. Replacement at high outdoor temperature: the heat pump
module of the unit is replaced with the boiler module if the
outdoor temperature rises above a given value. This criteri-
on is particularly useful in systems with low water content
and low energy demand with respect to the power of the
heat pump module.
To use this feature, set the threshold value of the outdoor
temperature in parameter 218.
To deactivate the replacement function, set parameter
218 to the maximum value allowed (40 °C).
The function is active by default and the value is set to
14 °C.
Even these two replacement functions use the filtered
value of the outdoor temperature.
3. Replacement on heat pump module limit thermostating
condition: the heat pump module of the unit is replaced
with the boiler module if the delivery and/or return tem-
perature of the heat pump module exceeds the permissible
operating limits (see Table 1.5
p. 23). Every 25’ the system
verifies whether the heat pump module can be reactivated.
This function can be modified or deactivated from parame-
ter 187.
To use this function, set parameter 187 to a value oth-
er than 0.0; a high value makes it less likely for the heat
pump module to be reactivated, thereby ensuring more
stable system operation; a low value favours the reacti-
vation of the heat pump module but makes it more likely
for the limit thermostating condition to reoccur.
To deactivate the replacement function, set parameter
187 to the minimum value allowed (0.0 K).
The function is active by default and the value is set to
3.0 K.
Integration and replacement mode on DHW service
If the control mode of the auxiliary boiler is integration and re-
placement (parameter 51 set to 4 by default), the system uses
certain replacement criteria of the heat pump module for the
DHW service, similarly to that for the space heating service.
The criteria used are those described in points 1 and 3 for the
space heating service and therefore, replacement at low out-
door temperature (depending on parameter 217) and replace-
ment on limit thermostating condition (depending on parame-
ter 187). On the other hand, no criterion of replacement at high
