Freestyle 2 Series Manual page 66

FreeStyle
®
2
series
27 Controls and operation
Adjustments for - Heating Only Boilers
with Outdoor sensor
Optional for Combi with Outdoor sensor
Theory of Outdoor Reset Control
One of the key points to boiler efficiency, is to match the
heat generated by the boiler to the heat loss of the building
to be able to obtain a given comfort level in the living space.
• You can obtain this efficiency by selecting a scale within an
operating programmed range of the boiler water temperature.
These scale ranges are related to the outdoor temperatures, and
boiler water temperatures for the installed radiation.
• These "Outdoor Reset Control" curves are graphed (and pro-
grammed into the control board) by outside temperature from
68 degrees to -4 degrees F and boiler water target temperatures
from 86 to 194 degrees F (see Figure 90, page 67), where the
heat loss of the home, will match the gradual increase in boiler
water temperature as the outside temperature drops.
• The average heat loss of a home may meet the needs (boiler wa-
ter temperatures) of offset curve number 6 (Figure 92, page 67)
to meet the heat loss at given outdoor temperatures.
• Another example would be a high heat loss structure, where
curve number 10 would drive up the boiler water temperature
with a slight drop in outdoor temperature. (from 68 degrees
F outside temperature to just a drop to 50 degrees F outdoor
temperature, see Figure 92, page 67).
• An example of a structure with very little heat loss, (such as
a super insulated, high efficiency building) would be curve
number 1, where the outdoor temperatures continue to drop,
and the boiler water temperatures are in the low range from 86
degrees to 104 degrees F.
Outdoor Reset Control (optional on the
Combi)
1. When the external outdoor sensor is attached to the boiler,
the system can work in Outside Temperature Compensation
mode. In OTC mode the temperature of the heating system is
controlled according to the external climate conditions, this will
insure a high degree of comfort and energy saving all year round.
2. By using the CH buttons (Items 3 and 4 - Figure 88) it is pos-
sible to set the maximum system water flow temperature for
the installation.
OTC setting - with Outdoor sensor
1. To enter the OTC - reset mode, press "reset" button for 5
seconds, takes you to Curve menu.
2. The display shows "CU" flashing Figure 88; to set Curve, use
the DHW buttons (Items 1 and 2 - Figure 88 ) pushing CH +
or - buttons switches your screens between CU (Curves) or
OF (Offset). Display "CU" allows Curves value adjustment,
value can be varied from 1 to 10, in accordance with the chart
on page 67. "O" means no OTC mode.
3. By pressing the CH push buttons (Items 3 and 4 - Figure 88 ,
the display shows "0F" flashing Figure 89; to set Offset, use
the DHW push buttons (Items 1 and 2 - Figure 88).
66
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wall mount gas fired water boiler
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boiler manual
(continued)
Figure 88
OTC settings
DHW
4. It can be 68 to 104, in accordance with the chart Fig-
ure 91, page 67 or Figure 92, page 67.
5. To exit the OTC mode, press OTC button "reset" button for
5 seconds.
Figure 89
OTC "OFFSET" settings
CH
In the case of an outdoor sensor failure,
will continue to operate the boiler, but without the use of
the Compensation Curves, and an error message will flash
on the display (Fault 39 -please see Figure 122, page 97).
Upon replacement of the defective sensor the boiler will
resume the use of Compensation Curves .
OTC Exempt mode
By pressing the DHW+ and eco buttons together for 10
seconds, it is possible to enter the OTC Exempt menu. The
display starts showing the value of the parameter OTC Exempt
(See parameter Number 163, page 109) flashing. By means of
the CH - push button it is possible to change value.
(Selecting 0 - allows you to Select the Compensation curve for
your individual home heating needs). By pressing DHW+
eco
and buttons together for 10 seconds, it is possible to leave
the OTC Exempt Menu. If no action has been taken, the con-
trol automatically leaves this mode after 2 minutes.
- 0 = installation non exempt from outside sensor connection;
- 1 = installation exempt for outside sensor connection;
Compensation curves
Curve numbers below refer to Figures 90, 91, & 92, on page 67.
• Curve number 1 is for a high efficiency home with very
low heat losses. (Least aggressive curve).
• Curve number 6 is for an average home heat losses.
• Curve number 10 is for a home with high heat losses.
• (Most aggressive curve).
eco
1 2
3 4
OTC/reset
OTC/reset
Part number 550-142-950/0122
the control